– INTRODUCTION :Transplant patients being immunocompromised are prone to have viral infections like cytomegalovirus (CMV), BK virus and Epstein-Barr virus, which remains a major cause of morbidity and mortality. HSCT patients have more chances of CMV reinfection and reactivation with the incidence of 16-56% and 30-70% than SOT. Previously only antiviral treatment for CMV was available but do have adverse effects so recently`to overcome these limitations , cell therapy like CMV-specific T-cell immune reconstitution was being developed. CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients.
This adoptive transfer not well studied in SOT due to weaken T cell response and might the recipient not tolerate donor delivered T lymphocytes (CLT),however , indicated for CMV viremia and refractory CMV in HSCT.
Mutiple studies have been conducted on T cell therapy in HSCT and SOT .One study substantiated that donor cell bank can be a source of CMV-specific CTLs in treating the CMV infection and thrombotic microangiopathy on D+/R-transplant patients. Similarly another study conducted with autologous invitro expanded T cells on lung transplant recipient (D+/R-) revealed good outcome for ganciclovir resistant CMV infection . Types of cellular therapy:
T-cell expiation
Direct selection using specific peptide MHC(PMHC)
T-cell generation using activation marker & engineered T cell (CAR,TCR): Cell therapy limitations and alternatives
Long term survival of the transfused cells affected , also increase chances of rejection, so genetic modification to these T cells and decreasing immunosuppressive post transfusion can help to solve this issue. Future directions and perspectives
1. Third-party CMV-specific T-cell banks
2. T-cell adoptive immunotherapy The role of Adoptive immunotherapy in different conditions related to transplantation
Prophylaxis and treatment of CMV Infection.
BK virus nephropathy.
EBV-associated lymphoproliferative disease.
During the last decades ,CMV resistence is emerging ,and one of the new stratigy is to use the CMV specific T cell receptors .
n this context, the use of adoptive transfer of CMV-specific T-cells has been widely investigated and applied to Hematopoietic Stem Cell Transplant patients and may be useful as a therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia in patients receiving a transplantation. However, only few authors have explored the use of T-cell adoptive transfer in SOT recipients. We propose a novel review in which we provide an overview of the impact of using CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients, the different approaches to stimulate, isolate and expand CMV-specific T-cells developed over the years and a discussion of the possible use of CMV adoptive cellular therapy in this SOT population. Given the timeliness and importance of this topic, we believe that such an analysis will provide important insights into CMV infection and its treatment/prevention.
The use of cellular therapy may be useful to reconstitute the CMV specific T-cell response and to control CMV viremia in SOT recipients. The use of CMV-specific T-cell adoptive transfer has promising results in treating CMV infection and disease, in ulcerative enteritis in primary immunodeficiency or in pediatric retinitis caused by CMV . Hematopoietic Stem Cell Transplant (HSCT) patients, adopt this as both prophylactically, to reconstitute protective antiviral immunity, and as a treatment in patients with refractory CMV infection.
Strategies for the generation of CMV-specific T-cells:
1- Ex vivo T-cell expansion requires the in vitro stimulation and expansion of T-cells using APCs presenting viral peptides or proteins.
2- Direct selection employs virus-derived peptide specific multimers in the setting of a HLA class-I molecule, viral antigen T-cell stimulation followed by cytokine expressing T-cell selection using antibody coated immunomagnetic beads or activation marker selection based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation.
3- Genetic manipulation requires gene transfer of high affinity CMV-specific T-cell receptors (TCR) or chimeric-antigen receptors (CAR) to change specificity of T-cells to CMV antigens.
Cell Therapy Limitations and Alternatives in SOT Patients:
The intensity and long-term immunosuppression requirement to prevent allograft rejection pre-disposes SOT recipients to a wide range of viral complications
In addition, antiviral treatment can generate side effects such as nephrotoxicity , and the selection of drug-resistant mutant CMV strains
A possible solution in order to overcome this problem, is to genetically modify the in vitro generated CTL to confer resistance to these drugs or decrease patient´s immunosuppression during a period post-infusion and use of third-party T-cells to infuse a kidney transplant patient who had ganciclovir resistant persistent CMV viremia, and decreased the levels of immunosuppressive drugs.
During the last decade, many studies have demonstrated the role of CMV specific T-cell immune response on controlling CMV replication and dissemination. In fact, it is well established that transplanted patients lacking CMV-specific T-cell immunity have an increased occurrence of CMV replication episodes and CMV-related complications. In this context, the use of adoptive transfer of CMV-specific T-cells has been widely investigated and applied to Hematopoietic Stem Cell Transplant patients and may be useful as a therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia in patients receiving a transplantation. However, only few authors have explored the use of T-cell adoptive transfer in SOT recipients. We propose a novel review in which we provide an overview of the impact of using CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients, the different approaches to stimulate, isolate and expand CMV-specific T-cells developed over the years and a discussion of the possible use of CMV adoptive cellular therapy in this SOT population. Given the timeliness and importance of this topic, we believe that such an analysis will provide important insights into CMV infection and its treatment/prevention.
New advances in cancer biology has resulted in highly specified immune therapy instead of toxic non-specific chemotherapy . Adoptive immunotherapy is a new way of treating malignancy by involving the patient own immune system to attack the cancer cell.It is a variant of transfusion therapy for malignancy, it was introduced with aim of eliminating tumour and preventing their relapse . It is still not widely used, but seem to have promising result in, even, metastatic cancer. It was found that subcutaneous growth of human tumor autografts to patients bearing advanced cancers was inhibited by the co transfer of autologous leukocytes in about half of the patients. Adoptive T cell therapy involves infusion of autologous and allogenic T cell in the patient with cancer. It uses tumour infiltrating lymphocyte (TIL) or chimeric antigen receptor (CAR) T cells. It is used in some cancers including metastatic melanoma.
USE OF ADOPTIVE TRANSFER OF CMVSPECIFIC T-CELLS IN THE CONTEXT OF SOLID ORGAN TRANSPLANTATION
It has promising results as a treatment for CMV infection and disease in ulcerative enteritis in primary immunodeficiency or in pediatric retinitis caused by CMV
It applied to (HSCT) patients, both prophylactically, and as a treatment in patients with refractory CMV infection
In contrast, in SOT recipients it has been less investigated
●In 2009, Brestrich et al. performed a study in a lung transplanted recipient with a severe and persistent CMV pneumonia resistant to ganciclovir and foscarnet.
The patient was treated with two infusions of 1 × 107/m2 CMV‐specific T-cells.
After the first infusion, the patient developed an overall improvement. However, the patient died due to graft failure with a negative biopsy for CMV antigen
●In one study, nineteen days following the infusion, a fifty fold decreased of the CMV DNA viral load was observed
The authors highlighted the effective application of CMV-specific CTLs from third donors, suggesting that creating donor cell-banks could be useful as a therapeutic alternative in SOT recipients
● In a later study, the same group successfully expanded autologous CMV-specific T-cells from a seronegative recipient that received a seropositive lung allograft and that developed a CMV disease due to ganciclovir resistant CMV infection.
The patient received four infusions of 3 × 107 autologous T-cells. After the infusion of the in vitro expanded T-cells no adverse events occurred, the CMV viral load became undetectable, the patient’s usual immunosuppression regime was resumed, hepatic and bone marrow function remained normal with no evidence of acute rejection.
These results indicated that adoptive therapy can contribute to immune control of CMV infection
CELLULAR THERAPIES AVAILABLE the conserved T-cell epitopes , has led to the improvement of the methods for ex vivo T-cell culture
rapid tests to evaluate the effector function of the CMV-specific T-cells have become available
T-Cell Expansion
A large number of antigens expressed at different stages during viral replication participate in the activation of both CMV-specific CD8+ and CD4+ T-cells
IE-1 and pp65 proteins are two of the most immunodominant CMV antigens
Different approaches have been carried out for in vivo expansion and generation of CMV-specific T-cells
CMV lysates or pp65-NLV peptide were used to stimulate CMV-specific T-cells
Using the pp65-NLV peptide only stimulated adoptive immunity against a single viral epitope and its application may be limited for HLA-A2patients/donors .
To overcome this problem, “polyspecific” products targeting multiple antigens were generated by incubating allogeneic T-cells in vitro with clusters of 15-mer peptides spanning the entire pp65 antigen to generate CMVspecific oligoclonal T-cells.
Direct Selection Using Specific Peptide–MHC (pMHC)
a previous knowledge about the immuno dominance of the epitopes is necessary.
HLA peptide tetramers from pp65 and IE-1 proteins have been previously used to select CD8+ T-cells that were further isolated using magnetic beads
This method allows to
●reduce the time and improve the quality of the final product
●minimizing alloreactivity .
the disadvantages of this technique
○ the limitation of the method to isolate only CD8+ or CD4 T-cell populations,
○ the irreversibility of the binding that can cause changes in the T-cell phenotype, leading to functional alterations of the purified T-cell population
Direct Selection Using Cytokine Capture System(CCS)
A rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral antigens
It has no HLA restriction and as an additional benefit stimulating and capturing a polyclonal population of CD4+and/orCD8+T-cells.
Kim et al. used the automated CliniMACS
Prodigy platform to generate pp65-specific CTL that exhibited functional activity, sustained antigen-specificIFN-g secretion, and cytotoxicity against pp65-pulsed target T-cells.
Although little clinical experience is available, this approach has the potential to be applicable to any type of patients with a clinical emergency due to CMV-related diseases including SOT recipients
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
It enables antigen recognition in a MHC independent manner and can be designed to specifically target conserved and essential epitopes of the selected antigen
CAR consists of a defined antigenbinding domain represented by a single-chain fragment variable (scFv) antibody, an extracellular spacer region, a transmembrane domain, and an intracellular domain that triggers T-cell activation, mainly by the T-cell receptor signaling domain.
In a recent study, CD4+ and CD8+ T-cells obtained from blood or cord blood of CMV-seronegative donors were transduced showing efficacy in preclinical models
While CAR-T-cell therapy identifies exclusively antigens located in the cell surface, TCR can also recognize intracellular antigenic fragments presented by MHC molecules. However, TCR T-cell therapy is restricted to MHC presentation, which represents a limitation of the strategy.
The main goal of TCR T-cells is to modify the TCR binding to the pathogen antigens. Naturally, the affinity of TCRs for the pathogen antigens is very low, which difficult the recognition.
To overcome this problem, modifications of the TCR using genetic engineering technology has been able to enhance the specificity and affinity of the recognition of the antigens by T-cells
Cell Therapy Limitations and Alternatives in SOT Patients
further development have been limited due to
● difficulties of Tcell expansion in SOT that are receiving immunosuppressive regimens
● the risk of graft rejection after T-cell administration.
One possible approach to overcome these limitations is generating ready to use third-party CMV-specific T-cell banks to ensure the availability of well characterized the T-cell products.
CONCLUSIONS
Recent findings regarding the development of new techniques to select, isolate and enrich functional CMV-specific T-cells and the possible generation of third party donor cell banks may help to use CMV-specific adoptive transfer as an alternative therapy for SOT recipients.
2- It may use in treatment of PTLD – BK – HCV- CMV after transplantation
Ganciclovir-resistant (GanR) cytomegalovirus (CMV) is an emerging clinical problem in organ transplant recipients, particularly recipients of kidney and pancreas and lung transplants. GanR CMV, a late posttransplantation complication, is observed predominantly among CMV-seronegative recipients of organs from seropositive donors, especially among recipients receiving intensive immunosuppression and having prolonged exposure to ganciclovir. Given the limitations of current diagnostic methods, if GanR CMV is clinically suspected, empirical treatment with intravenously administered foscarnet should be used in conjunction with reductions in immunosuppressive therapy and possibly CMV hyperimmune globulin. Better diagnostic tools and newer, less-toxic antiviral agents with different mechanisms of action are urgently needed to decrease the morbidity associated with this complication in organ transplant recipients.
Cytomegalovirus (CMV) infection remains a major complication following allogeneic hematopoietic stem cell transplantation (HSCT). T cell response plays a critical role in inducing long‐term immunity against CMV infection/reactivation that impairs during HSCT. Adoptive T cell therapy (ACT) via transferring CMV‐specific T cells from a seropositive donor to the recipient can accelerate virus‐specific immune reconstitution. ACT, as an alternative approach, can restore protective antiviral T cell immunity in patients. Different manufacturing protocols have been introduced to isolate and expand specific T cells for the ACT clinical setting. Nevertheless, HLA restriction, long‐term manufacturing process, risk of alloreactivity, and CMV seropositive donor availability have limited ACT broad applicability. Genetic engineering has developed new strategies to produce TCR‐modified T cells for diagnosis, prevention, and treatment of infectious disease. In this review, we presented current strategies required for ACT in posttransplant CMV infection. We also introduced novel gene‐modified T cell discoveries in the context of ACT for CMV infection.
CMV is one of the main causes of morbidity and mortality in immunocompromised individuals.
The incidence of CMV reactivation/reinfection in SOT is 16 to 56%.
CMV proliferation lead to viral syndrome ( gastroenteritis, pneumonitis,uveitis, hepatitis) and also cause indirect effects ( graft rejection, increased incidence of opportunistic infections and decreased recipient survival).
Cell mediated immune response is considered the most important arm of the immune system against CMV infection with the important role of CMV specific T cell in protecting against infection.
Although the use of antiviral medications is useful in treatment of CMV infection, but there is some issues about their high cost and their side effects . So there is a need for new therapeutic approaches.
The use of cellular therapy may be useful to reconstitute the CMV specific T cell response and to control CMV viremia in SOT recipients.
The use of adoptive transfer of CMV specific T cells in the context of SOT
CMV specific T cell transfer has been investigated and applied to HSCT patients as a protective antiviral immunity and as a treatment in patients with refractory CMV infection.
But in SOT recipients, it is less investigated due to the T cell response attenuation produced by the immunosuppression. Also SOT recipients may not tolerate donor derived cytolytic T lymphocytes due to stimulation of the alloreactive T cells and direct alloimmune injury.
Cellular therapies available
1.Ex vivo T cell expansion
Advantages: not restricted by HLA type, small blood volume required, naive donor can be used, generation of polyclonal T cells.
Disadvantages: extensive culture period, seropositive donors required.
2. Direct selection
PMHC multimer
Advantages : no needed extensive ex vivo manipulation and undergo rapid expansion in vivo.
Disadvantages: restricted by HLA type, seropositive donors
Cytoquine capture
Advantages: no needed extensive ex vivo manipulation and undergo rapid expansion,not restricted by HLA type
Disadvantages: require seropositive donors and large volume of blood.
3. Genetically engineered cells
Advantages: recognize antigens in a HLA independent manner, target conserved and essential epitopes.
Disadvantages: expensive, only surface antigens can be targeted, restricted by epitope.
Limitations
Deficiency of T cell differentiation.
Lifelong immunosuppression.
The role of adoptive immunotherapy
The adoptive transfer of CMV specific T cells is widely used and applied in hematopoietic stem cell transplant.
They may help to restore the CMV specific immunity for preventing infection in addition to serve as a treatment for CMV infection in SOT who don’t respond to conventional therapies such as infection with antiviral resistant strains.
During the last decade, many studies have demonstrated the role of CMV specific T-cell immune response on controlling CMV replication and dissemination. In fact, it is well established that transplanted patients lacking CMV-specific T-cell immunity have an increased occurrence of CMV replication episodes and CMV-related complications. In this context, the use of adoptive transfer of CMV-specific T-cells has been widely investigated and applied to Hematopoietic Stem Cell Transplant patients and may be useful as a therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia in patients receiving a transplantation.
In the context of transplantation, CMV-specific T-cell transfer has been widely investigated and applied to Hematopoietic Stem Cell Transplant (HSCT) patients, both prophylactically, to reconstitute protective antiviral immunity, and as a treatment in patients with refractory CMV infection . The most ambitious study carried out to date in SOT , was performed in a cohort of 21 SOT recipients (13 kidney, 8 lung and 1 heart) who developed recurrent ganciclovir resistant CMV infections. Thirteen of these patients (8 D+/R-, 3 D+/R+ and 2 D-/R-) were subjected to T-cell (ranging from 22.2-245 × 106 T-cells) adoptive transfer receiving a maximum of 6 doses one of which discontinued therapy after a single dose. Adverse events attributable to T-cell infusion were grade 1 or 2 (fatigue and malaise) with no adverse events associated with a change in the graft status. Eleven of the 13 showed objective improvement in their symptoms including a reduction (with a median drop of 1.2 × 103 CMV copies/mL) or resolution of CMV reactivation and resolution of CMV disease symptoms. In addition, the use of antiviral drug therapy was either completely stopped (in 5 of 11 patients) or significantly reduced (in 6 of 11patients). Evidences of immunological reconstitution was associated with control of viremia.
CELLULAR THERAPIES AVAILABLE
A) Ex vivo T-cell expansion requires the in vitro stimulation and expansion of T-cells using APCs presenting viral peptides or proteins.
(B) Direct selection employs virus-derived peptide specific multimers in the setting of a HLA class-I molecule, viral antigen T-cell stimulation followed by cytokine expressing T-cell selection using antibody coated immunomagnetic beads or activation marker selection based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation.
(C) Genetic manipulation requires gene transfer of high affinity CMV-specific T-cell receptors (TCR) or chimeric-antigen receptors (CAR) to change specificity of T-cells to CMV antigens. T
Cell Therapy Limitations and Alternatives in SOT Patients-
A).in vitro generated CMV -specific CTL are highly sensitive to immunosuppressive drugs (such as cyclosporin A and FK506) impairing the production of effector cytokines .
B)Another limitation is associated with deficiencies of T-cell differentiation in SOT recipients receiving immunosuppression.
C)Infusion of donor derive T-cells from donors may also transfer alloreactive T cells in numbers sufficient that could trigger episodes of rejection, particularly if the donor and the host differ in one or more HLA alleles
FUTURE DIRECTIONS AND PERSPECTIVES
The role of CMV-specific T-cell immune reconstitution after SOT have demonstrated several benefits, including lower risk of CMV infection and graft rejection. Thus, the development and improvement of new CMV-specific T-cell transfer based therapies could be a useful to adjust the therapeutic interventions . However, despite the increasing interest on adoptive CMV specific T-cell transfer, most of the information available comes from studies in HSCT recipients Only few reports including a small number of SOT recipients have used Tcell adoptive immunotherapy as a treatment of CMV infection or disease.Although promising results were obtained, further development have been limited due to difficulties of Tcell expansion in SOT that are receiving immunosuppressive regimens, and the risk of graft rejection after T-cell administration. .
Conclusion
Recent studies have significantly increased our knowledge about the protective role of CMV-specific T-cell immune response against CMV infection and disease. And thus the use of T-cell adoptive therapy may help to restore the CMV-specific immunity for preventing CMV infection in addition to serve as a treatment for CMV infections in SOT individuals who do not respond to conventional therapies, such as patients infected with antiviral resistant strains with no alternative treatment available.
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation
1. EBV-associated PTLD that persists following initial therapy 2.Resistant cases of CMV 3.BK virus Nephropathy 4.EBV virus infection
INTRODUCTION
Viral infection, including cytomegalovirus (CMV), BK virus and Epstein-Barr virus, remains a major cause of morbidity and mortality in immunocompromised individuals (1–5). While in immunocompetent individuals latent CMV infection is controlled by the immune system (6), in transplant recipients, both hematopoietic stem cell (HSCT) and solid organ transplantation (SOT), CMV infection is one of the main infectious complications.
Although the antiviral drugs to treat CMV infection have highly improved during the years, there are still some issues associated with the use of the available antivirals (ganciclovir, foscarnet, cidofovir and more recently letermovir) such as undesirable side effects (nephrotoxicity) and selection of resistance mutations in addition to the high cost.
T-Cell Expansion
To successfully generate and expand CMV-specific T-cells, it is crucial to define the most immunogenic epitopes used by the antigen presenting cells (APC) to promote the activation and proliferation of peptide-specific T-cells.
Direct Selection Using Cytokine Capture System (CCS)
CMV-specific T-cells can also be selected using IFN-g cytokine capture system (CCS), a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral antigens.
This strategy allows T-cell selection that in contrast with pMHC has no HLA restriction and as an additional benefit, stimulating and capturing a polyclonal population of CD4+ and/or CD8+ T-cells depending on the antigen used for stimulation, not achieved using the Streptamer strategy. Different authors have successfully isolated functional CMV-specific T-cells using this method.
Cell Therapy Limitations and Alternatives in SOT Patients
The intensity and long-term immunosuppression requirement to prevent allograft rejection pre-disposes SOT recipients to a wide range of viral complications (1). In addition, antiviral treatment can generate side effects such as nephrotoxicity (99), and the selection of drug resistant mutant CMV strains (100), limiting treatment capability in SOT recipients. Based on these limitations, cell therapy may be an appropriate and effective alternative antiviral treatment. However, as pointed out previously, deficiencies in T-cell differentiation and lifelong immunosuppression can affect to long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipients (76). Here, we analyze the alternatives available to overcome these limitations.
Conclusion
Recent findings regarding the development of new techniques to select, isolate and enrich functional CMV-specific T-cells and the possible generation of third-party donor cell banks may help to use CMV-specific adoptive transfer as an alternative therapy for SOT recipients. However, further work is clearly needed in order to fully understand and assess the clinical utility of these techniques in SOT recipients.
1. Please summarize this article. Introduction:
CMV infection is the main complication in both HSCT and SOT.
There’s is role of CMV specific T-cell immune response on controlling CMV replication and dissemination.
CMV specific T cell response can control replication and dissemination of the virus, ultimately eliminating it. USE OF ADOPTIVE TRANSFER OF CMV[1]SPECIFIC T-CELLS IN THE CONTEXT OF SOLID ORGAN TRANSPLANTATION:
The use of CMV-specific T-cell adoptive transfer is currently being evaluated for clinical application, with promising results as a treatment for CMV infection and disease in ulcerative enteritis in primary immunodeficiency or in pediatric retinitis caused by CMV. the use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment. CELLULAR THERAPIES AVAILABLE: I. T-Cell Expansion: requires the in vitro stimulation and expansion of T-cells using APCs presenting viral peptides or proteins. II. Direct selection:Employs virus-derived peptide specific multimers in the setting of a HLA class-I molecule, viral antigen T-cell stimulation followed by cytokine expressing T-cell selection using antibody coated immunomagnetic beads or activation marker selection based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation. III. Genetic manipulation: Requires gene transfer of high affinity CMV-specific T-cell receptors (TCR) or chimeric-antigen receptors (CAR) to change specificity of T-cells to CMV antigens. Advantages: Ex- vivo expansion: 1) Not restricted by HLA type. 2) small blood volume required. 3) naïve donor can be used. 4) generation of polyclonal T-cells. Direct Selection:
No needed extensive ex vivo manipulation and undergo rapid expansion in vivo. T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR):
§ Rapid detection and enrichment of T-cells; broader repertoire of antigen-specific T-cells
§ Compatible with other assay formats; not restricted by HLA
§ not needed previous information of immunodominant epitopes
§ no specialized APC such as dendritic cells are needed CONCLUSIONS:
According to current evidence showed promising result with the protective role of CMV specific T-cell immune response against CMV infection resistant to other antivirals. 2. Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation:
CMV infections – GCV-resistant; recurrent and refractory to antiviral therapy.
PTLD – refractory to Retuxi + Chemo-immunotherapy.
Introduction:
CMV is one of the most infections of transplant patients and associated with increase morbidity and mortality and decrease survival rate.
Over 75% of SOT patients are newly infected or activate latent infection after transplantation. Definitions: CMV infection: detection of CMV in the blood by culture, antigen test or PCR. CMV syndrome: detection of CMV in the blood with symptoms. CMV disease: detection of CMV by culture or histology in affected organs.
All organ donors and recipients should be screened for CMV (IgG antibody) serostatus prior to, or at the time of transplantation. CMV Prophylaxis:
By given valganciclovir prophylaxis to people receiving kidney and liver transplants for at least 3 months following transplantation if either:
1) The recipient is seronegative for CMV and receives an allograft from a CMV seropositive donor (D+/R-)
2) The recipient has received T-lymphocyte depletion therapy with Antithymocyte gobulin (ATG) or Alemtuzumab (Campath ), where donor: recipient serostatus is D+/R+ or D-/R+.
Valganciclovir prophylaxis given for people receiving heart, lung, intestinal or pancreas transplants for at least 3 months following transplantation if either:
1) The recipient is seronegative for CMV and receives an allograft from a CMV seropositive donor (D+/R-) [1C] OR
2) The recipient has received T-lymphocyte depletion therapy with Antithymocyte gobulin (ATG) or Alemtuzumab (Campath ), where donor: recipient serostatus is D+/R+ or D-/R+ [1C]
Do not routinely give Valganciclovir prophylaxis if donor and recipient are seronegative for CMV (D-/R-).
Administer Valganciclovir prophylaxis for at least 3 months after starting treatment for acute allograft rejection if either donor or recipient are CMV positive (D+/R-, D+/R+ or D-/R+. Laboratory Testing for CMV:
By Quantitative Nucleic Acid Testing (QNAT) of whole blood or plasma to quantify CMV viral load. Monitoring for CMV Infection and Disease:
Full Blood Count should be monitoring at least every 2 weeks whilst on Valganciclovir [1A].
Consider switching to CMV monitoring and pre-emptive therapy if people develop side effects e.g.; neutropenia, on Valganciclovir [1C]. Treating CMV Infection and Disease:
There is strong evidence to recommend a minimum 2 week course of oral valganciclovir for treatment of CMV infection and disease
CMV viral load should be checked after 2 and 3 weeks and treatment should only be discontinued when symptoms have resolved and there are 2 consecutive CMV virus titres below the locally-agreed threshold (the evidence for this recommendation is less robust). Ganciclovir resistance:
Develop by many risk factors which include:
A) prolonged course or subtherapeutic doses of anti-viral medication
B) D+/R-
C) intensive immunosuppression e.g. T-cell depleting agent.
D) lung transplant recipients.
When ganciclovir resistance is proven, stop ganciclovir or valganciclovir and offer Foscarnet treatment as an alternative. Immunosuppression dose reduction:
For adults, children and young people who develop CMV infection or disease (with or without leukopenia) following solid organ transplantation:
1) Consider a dose reduction of either calcineurin inhibitor or mycophenolate mofetil / azathioprine [1C].
2) Discuss with patients, and, where appropriate, parents or carers, the risk of acute rejection with immunosuppression dose reduction [1D].
3) Review the dosing of immunosuppression following resolution of CMV infection or disease [1D]. Information, education and support:
Appropriate patient counselling is important including helping SOT recipients understand their individualized risk profile based upon donor/recipient CMV serostatus and immunosuppression used.
CONCLUSIONS
Recent studies have significantly increased our knowledge about the protective role of CMV-specific T-cell immune response against CMV infection and disease. And thus the use of T-cell adoptive therapy may help to restore the CMV-specific immunity for preventing CMV infection in addition to serve as a treatment for CMV infections in SOT individuals who do not respond to conventional therapies, such as patients infected with antiviral resistant strains with no alternative treatment available. Recent findings regarding the development of new techniques to select, isolate and enrich functional CMV-specific T-cells and the possible generation of third party donor cell banks may help to use CMV-specific adoptive transfer as an alternative therapy for SOT recipients. However, further work is clearly needed in order to fully understand and assess the clinical utility of these techniques in SOT recipients.
Introduction; -Viral infection, including cytomegalovirus (CMV), BK virus and Epstein-Barr virus, remains a major cause of morbidity and mortality in immunocompromised individuals. -The incidence of CMV reactivation/reinfection in SOT is 16–56% , while in HSCT has been reported to be 30–70%. -Cell mediated immune response is considered the most important arm of the immune system against CMV infection with increasing evidences demonstrating a role of CMV-specific T-cells in protecting from infection, which can contribute to improve clinical care after transplantation.
Strategies for the generation of CMV-specific T-cells. Ex vivo T-cell expansion requires the in vitro stimulation and expansion of T-cells using APCs presenting viral peptides or proteins. Direct selection employs virus-derived peptide specific multimers in the setting of a HLA class-I molecule, viral antigen T-cell stimulation followed by cytokine expressing T-cell selection using antibody coated immunomagnetic beads or activation marker selection based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation
. Genetic manipulation requires gene transfer of high affinity CMV-specific T-cell receptors (TCR) or chimeric-antigen receptors (CAR) to change specificity of T-cells to CMV antigens
Cell Therapy Limitations and Alternatives in SOT Patients:
Deficiencies in T-cell differentiation and lifelong immunosuppression can affect to long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipients., can be overcome by:
Genetically modify the in vitro generated CTL to confer resistance to IS drugs.
Reducing the immunosupression drugs.
Promoting the generation of multiple polyfunctional effector functions that may be more effective in controlling CMV infection.
The creation of third-party cell banks
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
Adoptive immunotherapy can be used for prophylaxis and treatment of not only CMV, but also BKV, and PTLD. EBV can also be targeted using this method. Refractory infections and recurrent leukemia can specifically be treated using adoptive immunotherapy in solid organ transplant recipients and hematopoietic stem cell transplant recipients.
There’s is role of CMV specific T-cell immune response on controlling CMV replication and dissemination.
The use of adoptive transfer of CMV-specific T-cell may be useful as a therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia in patients receiving a transplantation.
USE OF ADOPTIVE TRANSFER OF CMVSPECIFIC T-CELLS IN THE CONTEXT OF SOLID ORGAN TRANSPLANTATION:
The use of CMV-specific T-cell adoptive transfer is currently being evaluated for clinical application, with promising results as a treatment for CMV infection and disease in ulcerative enteritis in primary immunodeficiency or in pediatric retinitis caused by CMV. the use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment.
CELLULAR THERAPIES AVAILABLE:
T-Cell Expansion:
Different approaches:
ICMV-specific CD8+ T-cell clones were generated by stimulating donor peripheral blood mononuclear cells (PBMC) with CMV-infected fibroblasts.
Discontinued risk of producing infection in patients.
Later, CMV lysates or pp65-NLV peptide were used to stimulate CMV-specific T-cells.
Using the pp65-NLV peptide only stimulated adoptive immunity against a single viral epitope and its application may be limited for HLA-A2 patients/donors . To overcome this problem, “poly.specific” products targeting multiple antigens were generated.
Direct Selection Using Specific Peptide–MHC (pMHC) :
Using pMHC multimers allows to isolate T-cells based on the Tcells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules.
Direct Selection Using Cytokine Capture System (CCS) :
CMV-specific T-cells can also be selected using IFN-g cytokine capture system (CCS), a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral antigens.
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR):
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR) .
is the gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR).
The generation of autologous CAR T-cells which has also been explored as immunotherapy against CMV enables antigen recognition in a MHC independent manner and can be designed to specifically target conserved and essential epitopes of the selected antigen overcoming pathogen escape mechanisms. .
Cell Therapy Limitations and Alternatives in SOT Patient:
Limitation:
Deficiencies in T-cell differentiation and lifelong immunosuppression can affect to long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipient. Solution:
Genetically modify the in vitro generated CTL to confer resistance to these drugs.
Decreasing patient´s immunosuppression during a period post-infusion.
Use of third-party CMV-specific Tells.
Another limitation:
Is associated with deficiencies of T-cell differentiation in SOT recipients receiving immunosuppression. Solution:
Promote the generation of CD8+ and CD4+ T-cells displaying multiple poly functional effector functions. Limitation:
Infusion of donor derive T-cells alloreactive T cells in numbers sufficient that could trigger episodes of rejection. Solution:
Is to extensive culturing T cells or even establishing T-cell clones to eradicate alloreactive T cells.
Third-party cell banks:
The creation of third-party cell banks as well as third party donor registries has emerged as a new
Possibility of treatment that employs T-cells derived from partially HLA-matched third party donors.
Such banks permit selection of T-cells on the basis of HLA allele phenotype, viral specificity and HLA restriction, which may provide distinct advantages, particularly in the treatment of HLA non-identical recipient.
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation:
The use of T-cell adoptive therapy may help to restore the CMV-specific immunity for preventing CMV infection in addition to serve as a treatment for CMV infections in SOT individuals who do not respond to conventional therapy ,such as patients infected with antiviral resistant strains with no alternative treatment available.
This article is relating CMV specific T cell transfer as a treatment for infection in solid organ transplant recipients. CMV specific T cell response can control replication and dissemination of the virus, ultimately eliminating it.
Discussion
Application of this method targeting CMV infection has been done in hematopoietic stem cell transplants as a form of treatment as well as prophylaxis, with good results. It can also be used in patients who are refractory to CMV treatment.
The reason this has not been tried widely in solid organ transplants is because IS regimen in these patients often suppresses T cell response effectively.
Different methods available include direct section and genetically engineered cells. Both have different advantages and disadvantages. For instance, ex vivo expansion or direct selection method requires seropositive donors and extensive culture period with one type needing large blood volumes while genetically engineered cells can demand more labour and even more time with restricted targets such as only surface antigens.
The first attempt at this method in SOT recipients was done in a lung transplant recipient who was resistant to ganciclovir and foscarnet in the treatment of resistant persistent CMV pneumonia. Although the patient improved initially, with observed reduction in viral land and symptoms of pneumonia, the patient’s condition worsened within a month (patient was still CMV positive), later resulting in death due to graft failure, but negative for CMV.
Since then, several trials have been conducted on SOT recipients with this method, especially with donor cell banks, and improvements have been made. Adverse events were minimal, with fatigue and malaise predominating as patient complaints. Graft status remained unaffected. Many patients have had their infection resolve with completion of antiviral therapy.
However, there are limitations that have been observed so far. One major limitation is the deficiency of T cell differentiation in SOT recipients receiving IS drugs. This can be allayed by finding methods to promote the generation of CD8+ and CD4+ T cells displaying multiple polydunctional effector functions so that CMV infection can be controlled effectively.
Conclusion
Although there is space for improvement, with further research being needed in this area, the use of CMV specific T cell adoptive transfer has shown good promise in treating infection in SOT recipients, especially when the infection is persistent or resistant to treatment, and with other options being limited.
Role of adoptive immunotherapy in transplantation
Adoptive immunotherapy can be used for prophylaxis and treatment of not only CMV, but also BKV, and PTLD. EBV can also be targeted using this method. Refractory infections and recurrent leukemia can specifically be treated using adoptive immunotherapy in solid organ transplant recipients and hematopoietic stem cell transplant recipients.
1. Please summarise this article. Introduction: Antivirals (ganciclovir, foscarnet, cidofovir, letermovir) have been the main stay of therapy for CMV infection post-transplant but associated with undesirable side effects (nephrotoxicity, bone marrow suppression, neuropathy, seizure) and development of resistance, in addition to high cost. Cell mediated immune response is considered the most important arm of the immune system against viral infections. Transplanted patients lacking CMV-specific T-cell immunity have an increased occurrence of CMV replication episodes and CMV-related complications. In this context, the use of cellular therapy may be useful to reconstitute the CMV specific T-cell response and to control CMV viremia in SOT recipients. In last decade, many studies have demonstrated the role of CMV specific T-cell immune response on controlling CMV replication and dissemination. Use of adoptive transfer of CMV-specific T-cells has been widely investigated and applied to HSCT patients and may be useful as a therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia in patients receiving a transplantation. Only few authors have explored the use of T-cell adoptive transfer in SOT recipients. This review article provides a synthesis of recent data regarding the impact of using CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients – the different approaches to stimulate, isolate and expand CMV-specific T-cells developed over the years and a discussion of the possible use of CMV adoptive cellular therapy in SOT population. CELLULAR THERAPIES AVAILABLE: Strategies to generate CMV-specific T-cells. (A) T-cell expansionex-vivo – Involves in vitro stimulation and expansion of T-cells using APCs presenting viral proteins or peptides – Crucial to define the most immunogenic epitopes used by the APC to promote the activation and proliferation of peptide-specific T-cells – IE-1 and pp65 proteins are two of the most immunodominant CMV antigen
– CMV lysates or pp65-NLV peptide used to stimulate CMV-specific T-cells
– “poly-specific” products targeting multiple antigens were generated by incubating allogeneic T-cells in vitro with clusters of 15-mer peptides spanning the entire pp65 antigen to generate CMV-specific oligoclonal T-cells. – Adoptive transfer of the oligoclonal T-cells were able to eliminate viremia, and infused cells persisted for up to two years. – The improvement of the methodology for ex vivo expansion has reduced the presence of alloreactive or naive T-cells in the final product (B) Direct selection Direct Selection Using Specific Peptide–MHC (pMHC)
– HLA-peptide tetramers from pp65 and IE-1 proteins have been used to select CD8+ T-cells that were further isolated using magnetic beads Streptamer technology – reduces the time and improve the quality of the final product, minimizing alloreactivity
– isolates CD8+ T-cells from CMV seropositive donors, demonstrating both immune reconstitution, as well as antiviral safety and efficacy after HSCT
– using partially HLA-matched CMV-specific T-cells obtained from a third party donor has shown to be safe to treat CMV infection in SOT patients,
Direct Selection Using Cytokine Capture System (CCS) – viral antigen T-cell stimulation followed by cytokine expressing T-cell selection using antibody coated immunomagnetic beads
– CMV-specific T-cells can also be selected using IFN-g cytokine capture system (CCS), a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral antigens
– Other selection strategy is to isolate and enrich activated viral-specific T-cells after antigen stimulation based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation, e,g CD137 C. Genetic manipulation T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR) – based on the gene modification of patient’s lymphocytes with CMV-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR) – to change specificity of T-cells to CMV antigens Advantages: Ex- vivo expansion – Not restricted by HLA type – small blood volume required – naïve donor can be used – generation of polyclonal T-cells Direct Selection – No needed extensive ex vivo manipulation and undergo rapid expansion in vivo Genetically engineered cells – Rapid detection and enrichment of T-cells; broader repertoire of antigen-specific T-cells – Compatible with other assay formats; not restricted by HLA – not needed previous information of immunodominant epitopes – no specialized APC such as dendritic cells are needed 2. Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
· CMV infections – GCV-resistant; recurrent and refractory to antiviral therapy
· PTLD – refractory to Retuxi + Chemo-immunotherapy
· Lymphoma (NHL)
· EB Virus infection
· BK Virus diseases
. Post-transplant viral infection has been the major cause of morbidity and mortality. In all recipient with SOT and with HSCT transplantations viral infection were the main complication. CMV seropositive recipients are more vulnerable to recurrent and super infection, the incidence of CMV reactivation/ reinfection in SOT is 16 to 56% with a median value of 30%, while in HSCT it is around 30 to 70%. There are two main mechanism of graft dysfunction secondary to CMV infection, CMV proliferation causing viremia, syndrome, and invasive disease, secondly, this indirectly causing graft rejection by immunomodulation. The cell mediated immune response is the first and most effective defense mechanism against CMV infection. During recent years the antiviral therapy has improved the graft survival, with some unwanted side effects. In this context the use of cellular therapy may be useful against CMV infection in SOT, where patients are immunocompromised, so the use of adaptive cellular therapy would be a hope in reactivation/ resistant cases of CMV patients. Use of Adaptive specific T-cell therapy in SOT;
. It was widely investigated and currently being used for resistant and reactivation of CMV disease. The procedure is CMV specific T-cells total two infusions with two weeks apart. Cellular therapies available;
. The strategies are ex vivo T cell culture, with advantage of no restriction by HLA type. T-cell expansion are epitopes pp65, IE-1, used by APC to activate and proliferate CMV-peptide specific T-cells. In direct selection of using specific peptide MHC based on TCR ability to bind a complex mixture of peptide loaded recombinant of HLA molecules. By direct selection using cytokine capture system with rapid assay that allows to select CD4 and CD8 inf gamma secreting T-cells. No HLA restriction. The gene modification of recipient T-cell with tumor specific T-cell receptors by T- cell generation using activation marker and engineered T-cells. Cell therapy limitation and alternatives in SOT patients;
. Selection of drug resistant mutant CMV strain, Nephrotoxicity, Deficiencies in T-cell differentiation and lifelong immunosuppression can affect long term survival of the transfused cells, Predisposition of variety of infections. Conclusion; . According to current evidence showed promising result with the protective role of CMV specific T-cell immune response against CMV infection resistant to other antivirals. Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation; . Treatment of BK virus, CMV, PTLD, and for rejection.
The use of CMV-specific T-cell adoptive transfer is currently being evaluated for clinical application, with promising results as a treatment for CMV infection and disease in ulcerative enteritis in primary immunodeficiency or in paediatric retinitis caused by CMV.
This manuscript provides a synthesis of recent data regarding the impact of using CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients, the different approaches to stimulate, isolate and expand CMV-specific T-cells developed over the years and a discussion of the possible use of CMV adoptive cellular therapy in these patients
Results from various studies suggest that, although there is still space for improvement, the use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment.
Strategies for the generation of CMV-specific T-cells.
(A) Ex vivo T-cell expansion requires the in vitro stimulation and expansion of T-cells using APCs presenting viral peptides or proteins.
(B) Direct selection employs virus-derived peptide specific multimers in the setting of a HLA class-I molecule, viral antigen T-cell stimulation followed by cytokine expressing T-cell selection using antibody coated immunomagnetic beads or activation marker selection based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation
.
(C) Genetic manipulation requires gene transfer of high affinity CMV-specific T-cell receptors (TCR) or chimeric-antigen receptors (CAR) to change specificity of T-cells to CMV antigens
Advantage:
Ex- vivo expansion
No restricted by HLA type
small blood volume required
naïve donor can be used
generation of polyclonal T-cells
Direct Selection
No needed extensive ex vivo manipulation and undergo rapid expansion in vivo
Genetically engineered cells
Rapid detection and enrichment of T-cells; broader repertoire of antigen[1]specific T-cells; Compatible with other assay formats; not restricted by HLA;
not needed previous information of immunodominant epitopes;
no specialized APC such as dendritic cells are needed
Adoptive immunotherapy in managing different conditions related to transplantation
Management of BK Virus, CM Virus, PTLD and rejection
CMV infection is a major cause of morbidity and mortality in immunocompromised individuals, with CMV seropositive HSCT patients presenting the highest risk of recurrent infections. CMV infection can increase the risk of graft rejection and decreased recipient survival. Cellular therapy may be useful to rebuild the T-cell response and control CMV viremia in SOT recipients.
USE OF ADOPTIVE TRANSFER OF CMV SPECIFIC T-CELLS IN THE CONTEXT OF SOLID ORGAN TRANSPLANTATION
CMV-specific T-cell transfer has been widely investigated and applied to Hematopoietic Stem Cell Transplant (HSCT) patients, both prophylactically, and as a treatment in patients with refractory CMV infection In SOT recipients it has been less investigated probably due to the T-cell response attenuation produced by the administration of the immunosuppressive therapy. The patient received 2 infusions (1.9 x 107 T cells/infusion) 2 weeks apart, with no side effects and with low CMV titers during two months after which a relapse of the viral load occurred. The most ambitious study carried out to date was performed in a cohort of 21 SOT recipients (13 kidney, 8 lung and 1 heart) who developed recurrent ganciclovir resistant CMV infections.
CELLULAR THERAPIES AVAILABLE:
During the last years a better understanding of the CMV-specific T-cell immunology such as the conserved T-cell epitopes ,has led to the improvement of the methods for ex vivo T-cell culture . In addition, rapid tests to evaluate the effector function of the CMV-specific T-cells have become available.
T-Cell Expansion
To successfully generate and expand CMV-specific T-cells, it is crucial to define the most immunogenic epitopes used by the antigen presenting cells (APC) to promote the activation and proliferation of peptide-specific T-cells . IE-1 and pp65 proteins are two of the most immunodominant CMV antigens and have been widely used to stimulate the CMV-specific immune response . T-cell ex vivo stimulation and expansion requires a small blood volume to establish the T-cell culture, making possible the generation of CMV-specific T-cells from low levels of circulating T-cells and naive donor sources.
Direct Selection Using Specific Peptide–MHC (pMHC)
HLA peptide tetramers from pp65 and IE-1 proteins have been previously used to select CD8+ T-cells that were further isolated using magnetic beads .However, the main disadvantages of this technique are related with the limitation of the method to isolate only CD8+ or CD4 T-cell populations, and the irreversibility of the binding . The Streptamer technology has been used to isolate CD8+ T-cells from CMV seropositive donors, demonstrating both immune reconstitution and antiviral safety and efficacy after HSCT. However, the selected T-cells are limited by the HLA restriction imposed by the Streptamer, limiting its use for adoptive therapy.
Direct Selection Using Cytokine Capture System (CCS) CMV-specific T-cells can also be selected using IFN-g cytokine capture system (CCS), this strategy allows T-cell selection that in contrast with pMHC has no HLA restriction and as an additional benefit, stimulating and capturing a polyclonal population of CD4+ and/or CD8+ T-cells depending on the antigen used for stimulation, not achieved using the Streptamer strategy. Another selection strategy is to isolate and enrich activated viral specific T-cells after antigen stimulation based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation, such as CD25, CD69, CD137 and CD154 .
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
The generation of autologous CAR T-cells which has also been explored as immunotherapy against CMV , CAR-T-cell therapy identifies exclusively antigens located in the cell surface, TCR can also recognize intracellular antigenic fragments presented by MHC molecules .
Cell Therapy Limitations and Alternatives in SOT Patients
The intensity and long-term immunosuppression requirement to prevent allograft rejection pre-disposes SOT recipients to a wide range of viral complications .Based on these limitations, cell therapy may be an appropriate and effective alternative antiviral treatment. However, as pointed out previously, deficiencies in-cell differentiation and lifelong immunosuppression can affect long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipients .
FUTURE DIRECTIONS AND PERSPECTIVES
Although promising results were obtained, further development have been limited due to difficulties of T Cell expansion in SOT that are receiving immunosuppressive regimens, and the risk of graft rejection after T-cell administration. Results from the ongoing clinical trial analyzing the safety and feasibility of administering CMV specific- CTLs from haploidentical donors in transplant patients would be of importance to implement T-cell adoptive therapy in SOT recipients.
CONCLUSIONS
The use of T-cell adoptive therapy may help to restore the CMV-specific immunity for preventing CMV infection in addition to serving as a treatment for CMV infections in SOT individuals who do not respond to conventional therapies. Possible generation of third party donor cell banks may help to use CMV-specific adoptive transfer as an alternative therapy for SOT recipients.
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
–In treatment and prevention of CMV ,BK virus nephropathy PTLD and rejection Reference :
There’s is role of CMV specific T-cell immune response on controlling CMV replication and dissemination.
the use of adoptive transfer of CMV-specific T-cell may be useful as a therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia in patients receiving a transplantation.
USE OF ADOPTIVE TRANSFER OF CMVSPECIFIC T-CELLS IN THE CONTEXT OF SOLID ORGAN TRANSPLANTATION
The use of CMV-specific T-cell adoptive transfer is currently being evaluated for clinical application, with promising results as a treatment for CMV infection and disease in ulcerative enteritis in primary immunodeficiency or in pediatric retinitis caused by CMV. the use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment.
CELLULAR THERAPIES AVAILABLE: T-Cell Expansion:
Different approaches:
ICMV-specific CD8+ T-cell clones were generated by stimulating donor peripheral blood mononuclear cells (PBMC) with CMV-infected fibroblasts.
Discontinued risk of producing infection in patients.
Later, CMV lysates or pp65-NLV peptide were used to stimulate CMV-specific T-cells.
Using the pp65-NLV peptide only stimulated adoptive immunity against a single viral epitope and its application may be limited for HLA-A2 patients/donors . To overcome this problem, “poly.specific” products targeting multiple antigens were generated.
Direct Selection Using Specific Peptide–MHC (pMHC) :
Using pMHC multimers allows to isolate T-cells based on the Tcells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules.
Direct Selection Using Cytokine Capture System (CCS) :
CMV-specific T-cells can also be selected using IFN-g cytokine capture system (CCS), a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral antigens.
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR) .
is the gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR).
The generation of autologous CAR T-cells which has also been explored as immunotherapy against CMV enables antigen recognition in a MHC independent manner and can be designed to specifically target conserved and essential epitopes of the selected antigen overcoming pathogen escape mechanisms. .
Cell Therapy Limitations and Alternatives in SOT Patient: Limitation:
Deficiencies in T-cell differentiation and lifelong immunosuppression can affect to long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipient.
Solution:
Genetically modify the in vitro generated CTL to confer resistance to these drugs.
Decreasing patient´s immunosuppression during a period post-infusion.
Use of third-party CMV-specific Tells.
Another limitation:
Is associated with deficiencies of T-cell differentiation in SOT recipients receiving immunosuppression.
Solution:
Promote the generation of CD8+ and CD4+ T-cells displaying multiple poly functional effector functions.
Limitation:
Infusion of donor derive T-cells alloreactive T cells in numbers sufficient that could trigger episodes of rejection.
Solution:
Is to extensive culturing T cells or even establishing T-cell clones to eradicate alloreactive T cells.
Third-party cell banks
The creation of third-party cell banks as well as third party donor registries has emerged as a new
Possibility of treatment that employs T-cells derived from partially HLA-matched third party donors.
Such banks permit selection of T-cells on the basis of HLA allele phenotype, viral specificity and HLA restriction, which may provide distinct advantages, particularly in the treatment of HLA non-identical recipient.
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
the use of T-cell adoptive therapy may help to restore the CMV-specific immunity for preventing CMV infection in addition to serve as a treatment for CMV infections in SOT individuals who do not respond to conventional therapy ,such as patients infected with antiviral resistant strains with no alternative treatment available.
The article deals with role of CMV-specific T cell adoptive transfer in CMV infected transplant recipients.
Introduction: Cytomegalovirus (CMV) is one of the main infection seen in transplant recipients, with maximum risk in CMV seropositive hematopoietic stem cell transplant (HSCT) recipients. CMV reactivation in solid organ transplant (SOT) is 16-56% while in HSCT, it is 30-70%. CMV infection causes direct effect on different organs (gastroenteritis, retinitis, encephalitis etc), as well as indirect effects like graft rejection, poor recipient survival, and opportunistic infections. CMV specific T cells protect from CMV infection. Antivirals used to treat CMV are associated with high costs, undesirable side effects, and resistance mutations. So, cellular therapy may be useful to control CMV viremia in SOT recipients.
Use of adoptive transfer of CMV specific T cells in SOT: It has been shown to be useful in treatment for CMV infection and disease in pediatric CMV retinitis, and ulcerative colitis in primary immunodeficiency. CMV-specific T-cell therapy has been used extensively in HSCT, but less evaluated in SOT (probably due to less tolerance to donor-derived cytolytic T lymphocytes). It has been tried in lung, kidney and heart transplants, with none of the patients showing any severe adverse effects. The studies suggest that CMV-specific T-cell adoptive transfer has role in SOT patients with limited options for CMV treatment.
Cellular therapies available: Improvement in methods for ex-vivo T-cell culture, and availability of rapid tests to evaluate effector function of CMV-specific T-cells has led to better understanding of their immunology. Strategies for T-cell generation include ex-vivo T cell expansion (using antigen presenting cells, APCs presenting viral peptides or proteins), Direct selection (using specific peptide MHC, using interferon gamma cytokine capture system, CCS, or using activation markers like CD25, CD69, CD137, and CD154), or using genetically engineered cells (gene transfer of high affinity CMV-specific T-cell receptors, TCR, and chimeric antigen receptors, CAR). Each of the methodology has its ow advantages and disadvantages. Ex vivo expansion requires seropositive donors, and takes prolonged time. Direct selection reduces time, increases quality, and decreases alloreactivity, but requires large blood volume. Genetic engineering is costly and MHC restricted.
Cell therapy limitations and alternatives in SOT patients: Cell therapy may be appropriate treatment option due to side effects of and resistance to antiviral therapies, but long-term immunosuppression affects long-term survival of transfused cells. Invitro CMV-specific cytotoxic T lymphocytes are highly sensitive to immunosuppressives like cyclosporine and tacrolimus, and hence require genetic modification to prevent being affected by the immunosuppressives, reduction in immunosuppressive dose in post-infusion period, or use of third party CMV-specific T-cells. T cell differentiation is deficient in SOT recipients, which would require efforts to promote generation of CD8+ and CD4+ T cell showing multiple polyfunctional effector functions. Infusion may transfer alloreactive T cells leading to episodes of rejection, it can be averted by extensive T-cell culturing. Third party cell banks and third party registries, offering multiple viral epitopes, help in getting rapid “off the shelf” products for a large number of patients.
Conclusion: CMV specific T cell immune reconstitution has shown lower risk of CMV infection and graft rejection, help to restore CMV specific immunity, and help in treating individuals resistant to conventional anti-CMV treatment.
2. Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
Adoptive immunotherapy has been shown to be useful in SOT patients with refractory CMV infection, HSCT patients with recurrent leukemia, in graft versus host disease, and against disease caused by other viral infections like adenovirus, BK virus etc.
CMV infection in SOT is one of major cause of morbidity and even mortality. The emergence of Ganciclovir resistance has further complicated the issue.
The concept of CMV specific adaptive T cell transfer looks fascinating to overcome this issue and has been widely investigated and applied to Hematopoietic Stem Cell Transplant patients and may be useful as a therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia in patients receiving a transplantation.
In contrast, in SOT recipients it has been less investigated probably due to the T-cell response attenuation produced by the administration of the immunosuppressive therapy. In addition, SOT recipients may not tolerate donor-
derived cytolytic T lymphocytes (CTLs) due to the activation of cytokine-mediated stimulation of the alloreactive T-cells causing direct alloimmune injury.
And thus the use of T-cell adoptive therapy may help to restore the CMV-specific
immunity for preventing CMV infection in addition to serve as a treatment for CMV infections in SOT individuals who do not respond to conventional therapies, such as patients infected with antiviral resistant strains with no alternative treatment available. Recent findings regarding the development of new techniques to select, isolate and enrich functional CMV-specific T-cells and the possible generation of third party donor cell banks may help to use CMV-specific adoptive transfer as an alternative therapy for SOT recipients. However, further work is clearly needed in order to fully understand and assess the clinical utility of these techniques in SOT recipients.
CMV, BK, EBV major cause of morbidity and mortality in immunocompromised individuals. Risk of recurrent infection: CMV seropositive allogeneic HSCT patients, R-/D+ SOT, HIV, patients who have received T-cell depletion therapies. The incidence of CMV reactivation/reinfection in SOT is 16–56%, with a median value of 30%
CMV-specific T-cell adoptive transfer used for CMV infection and disease in ulcerative enteritis in primary immunodeficiency or in paediatric retinitis caused by CMV CMV-specific CTLs from third donors used in KTRs (D+/R-) with refractory CMV infection showed good results with resolution of TMA features, suggesting that creating donor cell-banks could be useful as a therapeutic alternative in SOT recipients. Avaiable Cellular therapies A) T-Cell Expansion: Epitopes like pp65, IE-1 used by APC to activate and proliferate CMV-peptide-specific T-cells. Negative aspect is the use of a single viral epitope therefore its application may be limited for HLA-A2 patients/donors, and risk of producing infection later. B) Direct Selection Using Specific Peptide–MHC: Using pMHC multimers allows isolating T-cells based on TCR ability to bind a complex mixture of peptide-loaded recombinant HLA molecules. It only isolates only CD8, or CD4 T-cells; irreversible cell binding may alter the function of the T-cells. C) Direct Selection Using Cytokine Capture System: rapid assay that allows to select and enrich CD8+ and CD4+ INF-gamma secreting T-cells that have been previously stimulated using viral antigens. No HLA restrictions D) T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR): The gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR). Cell Therapy Limitations and Alternatives in SOT Patients: Deficiencies in T-cell differentiation and lifelong immunosuppression can affect to long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipients., can be overcome by:
Genetically modify the in vitro generated CTL to confer resistance to IS drugs.
Reducing the immunosupression drugs.
Promoting the generation of multiple polyfunctional effector functions that may be more effective in controlling CMV infection.
The creation of third-party cell banks
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation: Treatment and prevention of CMV, BKV, PTLD, rejection
Summary
· T cell mediated immune response plays important role to prevent viral replication in transplant recipients.
· Use and infusion of CMV specific T cells can be beneficial in treatment of refractory cases.
· In addition, it will be better option of treatment to avoid risk of nephrotoxicity and anti viral resistance associated with the use of antivirals as ganciclovir, foscarnet and cidofovir.
· May steps are essential to get CMV specific T lymphocytes:
§ Ex vivo expansion of T cells by using APC carrying viral antigens.
§ Direct selection of T cells using cytokine capture system.
§ Genetic engineering to transfer high CMV affinity cells. Other uses of it in the field of transplantation:
· In EBV related PTLD (when resistant to reduction of IS and classic chemotherapy, CHOP protocol).
· Refractory cases of BKN, not responding to reduction of immunosuppression. Management of graft versus host diseas
Introduction ▪︎CMV infection in transplant recipients is one of the main infectious complications. The incidence of CMV reactivation/ reinfection in SOT is 16–56%.
▪︎It can cause direct effects and indirect effects related with increased incidence of graft rejection and opportunistic infections or decreased recipient survival. ▪︎Cell mediated immune response is considered the most important arm of the immune system against CMV infection with increasing evidences demonstrating a role of CMV-specificT-cells in protecting from infection. ▪︎There are still some issues associated with the use of the available antivirals (ganciclovir, foscarnet, cidofovir and more recently letermovir) such as undesirable side effects (nephrotoxicity) and selection of resistance mutations in addition to the high cost. Consequently,strong efforts have been made to search for new therapeutic approaches. In this context, the use of cellular therapy may be useful to reconstitute the CMV specific T-cell response and to control CMV viremia in SOT recipients. ▪︎This study provided a synthesis of recent data regarding the impact of using CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients, the different approaches to stimulate, isolate and expand CMV-specific T-cells developed over the years & a discussion of the possible use of CMV adoptive cellular therapy in these patients.
☆ The use of adoptive transfer of CMV specific T-cells in the context of solid organ transplantation ▪︎ CMV-specific T-cell transfer has been widely investigated and applied to Hematopoietic Stem Cell Transplant (HSCT) patients as prophylaxis and treatment. ▪︎In SOT recipients it has been less investigated probably due to the T-cell response attenuation and recipients may not tolerate donor derived cytolytic T lymphocytes (CTLs). ▪︎Few authors have explored the use of T-cell adoptive transfer in SOT recipients during the last decade ▪︎A number of authors have explored the potential of T-cell adoptive transfer as a therapy in SOT recipients. ▪︎A study highlighted the effective application of CMV-specific CTLs from third donors. ▪︎Some studies indicated that adoptive therapy can contribute to immune control of CMV infection. ▪︎Some trial suggested that; the use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment.
☆ CONCLUSION ▪︎The use of T-cell adoptive therapy may help to restore the CMV-specific immunity for preventing CMV infection in addition to serve as a treatment for CMV infections in SOT individuals who do not respond to conventional therapies, such as patients infected with antiviral resistant strains with no alternative treatment available.
Dear All
Thank you for understanding the basis of adoptive immunotherapy in the context of refractory CMV infection/disease. As you can see the crucial role of cell mediated immunity in clearing CMV infection. What about antibody mediated component in fighting CMV infection given the fact that seronegative recipients are at high risk of infection from seropositive donors?
The role of humoral immunity can be simulated by using CMV IVIG (cytomegalovirus immune globulin) which may have a role in the management of drug-resistant CMV infection. However, a well-designed RCT to evaluate the efficacy of this approach is still awaited (1).
Introduction · Viral infections like CMV, EBV and BK virus cause significant morbidity and mortality in immunocompromised patients. · The incidence of CMV reactivation/reinfection in SOT is 16–56% , while in HSCT has been reported to be 30–70%. · CMV seropositive HSCT, and CMV D+/R- predict a high risk of recurrence of infection · Cell mediated immune response is the most significant arm to prevent CMV disease. · The role of CMV specific T-cells in term of protection from infection is paramount. · Anti virals against CMV having undesirable side effects including nephrotoxicity. · So, the use of cellular therapy may be helpful to reconstitute the CMV specific T-cell response and to control CMV viremia in SOT recipients.
Use of adoptive transfer of CMV-specific T cell in the context of SOT · The use of CMV-specific T-cell adoptive transfer is currently being evaluated for clinical application, with promising results as a treatment for CMV infection and disease · The period early after the transplant is considered critical due to the high risk of infections associated with a high incidence of CMV. · The CMV-specific T-cell transfer has been well researched and applied to HSCT patients, prophylactically, to reconstitute protective antiviral immunity, and as a treatment in patients with refractory CMV infection · The role of CMV-specific T-cell immune reconstitution after SOT have demonstrated several benefits, including lower risk of CMV infection.
Methods of generating CMV specific T cell: · T-cell expansion · Direct selection using specific peptide – MHC · Direct selection using cytokine capture · T cell generation using activation marker and engineered T-cells Cell therapy limitation and alternative in SOT patient
Predisposition to wide variety of viral infections complications due to higher intensity and long-term immunosuppression
Selection of drug resistant mutant CMV strain, limiting treatment capability in SOT recipients.
Caused adverse effect like nephrotoxicity
Deficiencies in T-cell differentiation and lifelong immunosuppression can affect long-term survival of the transfused cells, interfering the antiviral functionality and limiting its use for adoptive therapy in SOT recipients
Conclusion The use of T-cell adoptive therapy may help in SOT individuals who do not respond to conventional therapies, such as patients infected with antiviral resistant strains. The role of Adoptive immunotherapy in managing different conditions related to transplantation
Treatment of resistant EBV PTLD
The treatment for resistant cases of CMV, BK nephropathy
Thank you for summary. You referred to the use of adoptive immunotherapy in the treatment of resistant EBV PTLD. Are you aware of antivirals specific to EBV to produce any resistant strains?
Is It Feasible to Use CMV-Specific T-Cell Adoptive Transfer as Treatment Against Infection in SOT Recipients?
Transplanted patients lacking CMV-specific T-cell immunity have an increased occurrence of CMV replication episodes and CMV-related complications. Introduction.
Viral infection, including cytomegalovirus (CMV), BK virus and Epstein-Barr virus are considered common viral infection in immunocompromised group, CMV seropositive allogeneic HSCT patients presents the highest risk of recurrent infections, followed by CMV seronegative SOT recipients that receive a graft from a seropositive donor (R-/D+), HIV patients, and patients who have received T-cell depletion therapies (Alemtuzumab, antithymocyte globulin, or post-transplant cyclophosphamide).
Direct effects of CMV proliferation causing viral syndrome with clinical manifestations such as (gastroenteritis, pneumonitis, hepatitis, uveitis, retinitis, encephalitis and graft rejection).
CMV infection also cause indirect effects related with increased incidence of graft rejection and opportunistic infections or decreased recipient survival, the use of the available antivirals (ganciclovir, foscarnet, cidofovir and more recently letermovir) is effective but have undesirable side effects (nephrotoxicity) now the role of cellular therapy such as CMV-specific T-cell adoptive has effect on CMV viremia. USE OF ADOPTIVE TRANSFER OF CMVSPECIFIC T-CELLS IN THE CONTEXT OF SOLID ORGAN TRANSPLANTATION.
Using in severe and persistent CMV pneumonia resistant to ganciclovir and Foscarnet and shown decreasing in viral load and improving of clinical manifestation and these results suggest that, although there is still space for improvement, the use of CMV-specific T-cell adoptive
transfer is promising in SOT recipients with limited options for CMV-infection treatment. CELLULAR THERAPIES AVAILABLE. T-Cell Expansion.
IE-1 and pp65 proteins are two of the most immunodominant CMV antigens and have been widely used to stimulate the CMV-specific immune response. T-cell ex vivo stimulation and expansion requires a small blood volume to establish the T-cell culture, making possible the generation of CMV-specific T-cells from low levels of circulating T-cells and naive donor sources. Direct Selection Using Specific Peptide–MHC (pMHC).
This method allows to reduce the time and improve the quality of the final product, minimizing alloreactivity. Direct Selection Using Cytokine Capture System (CCS).
CMV-specific T-cells can also be selected using IFN-g cytokine capture system (CCS), a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral antigens. T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR).
By modifications of the TCR using genetic engineering technology has been able to enhance the specificity and affinity of the recognition of the antigens by T-cells. Cell Therapy Limitations and Alternatives in SOT Patients.
1-lifelong immunosuppression can affect to long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipients.
2-Deficiencies of T-cell differentiation in SOT recipients receiving immunosuppression.
3-Infusion of donor derive T-cells from donors may also transfer alloreactive T cells in numbers sufficient that could trigger episodes of rejection.
4-Selection of T-cells on the basis of HLA allele phenotype, viral specificity and HLA restriction by using third party cell banks. CONCLUSIONS
The protective role of CMV-specific T-cell immune response
against CMV infection and disease is now clear enough with good and promising result, and thus the use of T-cell adoptive therapy may help to restore the CMV-specific specially with disseminated and anti-viral resistance infection.
IS IT FEASIBLE TO USE CMV SPECIFIC T CELL ADOPTIVE TRANSFER AS TX AGAINST INFECTION IN SOT RECIPIENTS?
Introduction.
-CMV,BK & EBV are major causes of morbidity and mortality in immunosuppressed.
-Incidence of CMV reactivation or reinfection is 30-70%;median 37%.
-Antiviral meds have been the mainstay of treatment for CMV but with increased SE, cellular therapy is being explored to assess whether we can better our outcomes post transplant.
Use of adoptive transfer of CMV specific T cells in context of SOT.
-CMV specific T cells used in HSCT > SOT.
-Cytotoxic T cells are harvested from pts peripheral blood mononuclear cells, stimulated, set aside and infused in patients. Infused cells can last up to 24 months. T cells preparation (expansion + stimulation) can be ex vivo or in vivo with the former needing less blood to get a T Cell culture.
-A number of studies on these are ongoing before level of safety and efficacy can be established.
Cellular therapies available.
1.T cell expansion
-IE & PP65 proteins are CMV ag used to stimulate CMV immune response.
-In vivo expansion and generation of CMV specific T cells involves;
CMV specific CD8 T cells produced by stimulating PBMC with CMV infected fibroblasts.
CMV lysate/PP65-NLV peptide used to stimulate CMV T cell.
-Ex vivo expansion needs a small qty of blood for T cell culture thus making generation of CMV T cells possible from low circulating levels of T cells.
2.Direct selection using specific peptide MHC(pMHC)
-T cells are isolated based on T cell receptor ability to get attached to a mixture of peptide loaded recombinant HLA molecule.
3.Direct selection using cytokine capture system(CCS)
-CMV specific T cell isolated by interferon gamma CCS facilitating T cell selection that unlike pMHC lacks HLA restriction.
4.T cell generation using activated marker and engineered T cells.(CAR,TCR)
-CAR entails a specific Ag binding domain represented by a single chain fragment variable Ab, extracellular spacer, transmembrane and an intracellular region that activates T cells.
-TCR uses heterodimers integrated by alpha and beta peptide chains to identify specific peptides presented by MHC complexes.
Cell therapy limitations and alternatives in SOT pts.
-Duration and intensity of immunosuppression leads to viral infection in SOT.
-Antivirals have SE; Nephrotoxicity and drug resistant CMV strain.
-Deficiencies of T cell differentiation in SOT recipients getting immunosuppression.
-Solution to some of the aforementioned is RIS during the post infusion phase to allow for expansion and functionality of CMV specific T cell.
FUTURE DIRECTIONS AND PERSPECTIVE.
-CMV specific T cell immune reconstitution post SOT have advantages ;Less risk of CMV infection and graft rejection.
-3rd party CMV specific T cells can be used to overcome challenges with enrolling SOT in clinical trials; Difficulty of T cell expansion in SOT recipients on immunosuppressive therapy, increased risk of graft rejection and T cell administration.
ROLE OF ADOPTIVE IMMUNOTHERAPY IN OTHER CONDITIONS RELATED TO TRANSPLANT.
GVHD is one of the complications post transplant, Adoptive immunotherapy has been tried in a few studies to try institute long term peripheral tolerance and decrease GVHD incidence while preserving anti leukemic immunity. In another study GVHD incidence was postulated to decrease by modifying adoptive immunotherapy by decreasing the CD8 +VE T cells from lymphocyte concentrate or transfusing very low number of cells and increasing the dose in a systematic manner.
REFERENCES;
1.Alice et al-Graft engineering and adoptive immunotherapy; New approaches to promote immune tolerance after hematopoietic stem cell transplantation. Front Immunology .vol 10-2019
2.Kolb et al – Adoptive immunotherapy with donor lymphocyte transfusion. Current opinion in oncology9(2);p 139-145,March1997
3.Lingling Zhang et al- Advances in targeted immunotherapy for graft versus host disease; Front immunol.2018;9;1087
4.Lukas M Braun et al ; Immunomodulatory therapies for treatment of graft versus host disease. Hemasphere 2021 njun;5(6);e581
# Introduction:
*Viral infection, including (CMV), (BKV) and (EBV), still considered as a main cause of morbidity and mortality in immunocompromised individuals.
*In (HSCT) and (SOT) recipients, CMV infection is one of the main infectious complications.
*The incidence of CMV reactivation/reinfection in SOT is 30%.
*It cause proliferation that lead to viral syndrome with clinical manifestations such as (gastroenteritis, pneumonitis, hepatitis, uveitis, retinitis and encephalitis), with increased incidence of graft rejection and opportunistic infections or decreased recipient survival.
*Cell mediated immune response is considered the most important arm of the immune system against CMV infection.
*Using both immunological and virological monitoring may facilitate clinical decisions during follow-up of SOT recipients *The use of cellular therapy may be useful to reconstitute the CMV specific T-cell response and to control CMV viremia in SOT recipients and mainly using CMV-specific T-cell adoptive transfer on the control of CMV infection.
# Use of adoptive transfer of CMV specific T- cell in the context of SOT:
*The use of CMV-specific T-cell adoptive transfer is widely investigated and applied to (HSCT) patients, but in SOT recipients it has been less investigated probably due to the T-cell response attenuation produced by the administration of the immunosuppressive therapy.
* SOT recipients may not tolerate donor derived (CTLs) due to the activation of cytokine-mediated stimulation of the alloreactive T-cells causing direct alloimmune injury.
*Many studies results indicated that adoptive therapy can contribute to immune control of CMV infection.
#T-Cell Expansion
*To successfully generate and expand CMV-specific T-cells, it is crucial to define the most immunogenic epitopes used by (APC) to promote the activation and proliferation of peptide-specific T-cells.
*IE-1 and pp65 proteins are two of the most
immunodominant CMV antigens and have been widely used to
stimulate the CMV-specific immune response.
# Direct Selection Using Specific Peptide–MHC (pMHC)
Using pMHC multimers allows to isolate T-cells based on the Tcells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules.
# Direct Selection Using Cytokine Capture System (CCS):
Using IFN-g cytokine capture system (CCS), a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral antigens.
# T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
It is the gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR) and can be designed to specifically target conserved and essential epitopes of the selected antigen .
# Cell Therapy Limitations and Alternatives in SOT Patients
*The intensity and long-term IS requirement to prevent allograft rejection lead to a wide range of viral complications.
Antiviral treatment can generate side effects such as nephrotoxicity.
Selection of drug-resistant mutantCMVstrains limiting treatment capability in SOT recipients.
IV. Is It Feasible to Use CMV-Specific T-Cell Adoptive Transfer as Treatment Against Infection in SOT Recipients?
Summarise this article.
Introduction
Viral infections (e.g., CMV, EBV, BKV) are a major cause of morbidity and mortality in immunosuppressed patients. CMV infection increases the risk of graft rejection and also contributes to poor graft and patient survival.
The cell-mediated immune response plays a significant role against CMV infection. Transplant recipients lacking CMV-specific T-cell immunity are at an increased risk of CMV replication and CMV-related complications. Therefore, cellular therapy may be necessary to reconstitute the CMV-specific T-cell immune response.
Use of adoptive transfer of CMV-specific T-cells in the context of SOT
In hematopoietic stem cell transplant (HSCT), use of adoptive transfer of CMV-specific T-cells has been widely studied and applied. It has been used to reconstitute the protective antiviral immunity and as a treatment option in patients with refractory CMV infection.
Cells are obtained from the patient’s peripheral blood mononuclear cells (PBMC) then they are stimulated, isolated, expanded and infused back into the patient. This treatment option is associated with immunological reconstitution and control of the viremia.
Infused cells can last up to 2 years. T-cell stimulation and expansion can be done in vivo or ex vivo, the latter requires a small blood volume to establish the T-cell culture.
There is a clinical trial assessing the biological efficacy of therapeutically administered donor-derived specific cytotoxic T lymphocytes (CTLs) targeting CMV following SOT or allogeneic blood or marrow stem cell transplant.
Cellular therapies available: –
These are the methodologies used to generate CMV-specific T-cells.
T-cell expansion
In order to generate and expand CMV-specific T-cells, it is important to identify the most immunogenic epitopes used by the APCs to promote the activation and proliferation of peptide-specific T-cells
Direct selection using specific peptide-MHC (pMHC)
Use of pMHC multimers allows isolation of T-cells based on the T-cells receptor ability to bind a mixture of peptide-loaded recombinant HLA molecules.
Advantage – reduces time spent and improves the quality of the final product hence minimizing alloreactivity
Disadvantage – can only isolate CD8+ OR CD4+ T-cells
Partially HLA-matched CMV-specific T-cells obtained from a third-party donor can be used to minimize the challenges associated with this therapy.
Direct selection using cytokine capture system (CCS)
CCS is a rapid assay used to select and enrich CD8+ and CD4+ T-cells that had been previously stimulated using viral antigens.
Unlike pMHC it has no HLA restriction.
Cells can also be isolated based on the detection of specific surface molecules which are selectively expressed or strongly up-regulated following T-cell activation e.g., CD25, CD69, CD137 and CD154.
T-cell generation using activation marker and engineered T-cells (CAR, TCR)
Involves gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR). Further clinical studies are needed to demonstrate in vivo efficacy.
CAR-T-cell therapy recognizes antigens exclusively located on the cell surface while TCR can also identify intracellular antigenic fragments presented by MHC molecules.
Disadvantage – TCR T-cell therapy is restricted to MHC presentation
The main aim of TCR T-cells is to modify the TCR binding to pathogenic antigens.
The affinity of TCRs for pathogenic antigens is naturally low hence, genetic engineering technology is used to modify and overcome this problem.
Cell therapy limitations and alternatives in SOT patients
Duration and intensity of immunosuppression predisposes SOT recipients to viral infections.
Antiviral treatment is associated drug toxicities e.g., nephrotoxicity as well as development of drug-resistant CMV strains.
In view of these limitations, cell therapy serves as an appropriate and effective alternative to antiviral treatment.
Limitations of cell therapy include deficiencies in T-cell differentiation and chronic immunosuppression which can affect the long-term survival of the transfused cells. These limit its use in SOT recipients.
The solution to these limitations includes decreasing the immunosuppression dose during the post-infusion period. This allows the expansion and functionality of the CMV-specific T-cells.
Third-party CMV-specific T-cells can also be used.
Future directions and perspectives
In SOT recipients, CMV is associated with severe complications like graft loss.
CMV-specific T-cell immune reconstitution following SOT reduces the risk of CMV infection and graft rejection.
Enrolling SOT recipients into clinical trials is difficult due to challenges of T-cell expansion in SOT recipients on immunosuppressive therapy as well as the increased risk of graft rejection after T-cell administration. To overcome this challenge, third-party CMV-specific T-cells can be used.
Conclusions
There is a defined protective role of CMV-specific T-cell immune response against CMV infection and disease.
Use of the T-cell adoptive immunotherapy helps restore the CMV-specific immunity for prevention of CMV infection as well as for treatment of CMV infection and CMV disease in SOT recipients who fail to respond to the conventional therapies e.g., patients with a drug-resistant CMV strain.
More clinical trials are needed to fully elucidate and assess the clinical utility of these techniques in the SOT recipient population.
Address the role of adoptive immunotherapy in managing different conditions related to transplantation.
In adoptive immunotherapy, T-cells are stimulated, isolated, expanded and infused back into the patient to treat/ control a certain condition.
– To prevent rejection in living donor kidney transplant recipients (TRACT Trial) (4)
– Management of GVHD (graft versus host disease) (5)
References
1. Jahan S, Scuderi C, Francis L, Neller MA, Rehan S, Crooks P, et al. T-cell adoptive immunotherapy for BK nephropathy in renal transplantation. Transplant infectious disease : an official journal of the Transplantation Society. 2020 Dec;22(6):e13399. PubMed PMID: 32608543. Pubmed Central PMCID: PMC7816252. Epub 2020/07/02. eng.
2. Parajuli S, Jorgenson M, Meyers RO, Djamali A, Galipeau J. Role of Virus-Specific T Cell Therapy for Cytomegalovirus and BK Infections in Kidney Transplant Recipients. Kidney360. 2021 May 27;2(5):905-15. PubMed PMID: 35373059. Pubmed Central PMCID: PMC8791350. Epub 2022/04/05. eng.
3. Heslop HE, Sharma S, Rooney CM. Adoptive T-Cell Therapy for Epstein-Barr Virus-Related Lymphomas. Journal of clinical oncology : official journal of the American Society of Clinical Oncology. 2021 Feb 10;39(5):514-24. PubMed PMID: 33434061. Pubmed Central PMCID: PMC8462582. Epub 2021/01/13. eng.
4. Mathew JM, J HV, LeFever A, Konieczna I, Stratton C, He J, et al. A Phase I Clinical Trial with Ex Vivo Expanded Recipient Regulatory T cells in Living Donor Kidney Transplants. Scientific reports. 2018 May 9;8(1):7428. PubMed PMID: 29743501. Pubmed Central PMCID: PMC5943280. Epub 2018/05/11. eng.
5. Trzonkowski P, Bieniaszewska M, Juścińska J, Dobyszuk A, Krzystyniak A, Marek N, et al. First-in-man clinical results of the treatment of patients with graft versus host disease with human ex vivo expanded CD4+CD25+CD127- T regulatory cells. Clinical immunology (Orlando, Fla). 2009 Oct;133(1):22-6. PubMed PMID: 19559653. Epub 2009/06/30. eng.
Is It Feasible to Use CMV-Specific T-Cell Adoptive Transfer as Treatment Against Infection in SOT Recipients?
Estefani Garcia-Rios et al. in this review article examined the utility of cellular therapy in the reconstitution of the CMV specific T-cell response and controlling CMV viremia in recipients of solid organ transplants. This article elucidates on a review of recent data concerning the impact of using CMV-specific T-cell adoptive transfer on the control of CMV infection in recipients of solid organ transplants, the various approaches to stimulate, isolate and expand CMV-specific T-cells developed over time and a highlight of the potential utility of CMV adoptive cellular therapy in these patients.
Use of Adoptive Transfer of CMV-Specific T-Cells in the Context of Solid Organ Transplantation A promising outcome of treatment using adoptive CMV-specific T-cell transfer has been observed in treatment of CMV infection and disease, ulcerative enteritis in primary immunodeficiency and in pediatric retinitis caused by CMV. In transplantation medicine, CMV-specific T-cell transfer has been studied extensively and found useful in Hematopoietic Stem Cell Transplant (HSCT) recipients, both for prophylaxis and reconstitution of antiviral immunity, and as a treatment option in refractory CMV infection. However, in SOT recipients investigated has been limited probably due to the poor T-cell response caused by the administration of the immunosuppressive therapy. Additionally, SOT recipients may reject donor-derived cytolytic T lymphocytes (CTLs) due to the activation of cytokine-mediated stimulation of the alloreactive T-cells. Brestrich et al. in a study of lung transplanted recipient with severe and drug resistant CMV pneumonia infused CMV- specific T cells 4 weeks apart. There was an improvement after the first infusion but the patient died due to graft failure with a negative biopsy for CMV antigen. Thereafter many other studies have been done in the past decade to build on this and have shown favorable response. The most notable of these studies was done in 21 SOT recipients who had recurrent ganciclovir resistant CMV infections. Thirteen of the study participants were subjected to T-cell adoptive transfer receiving a maximum of 6 doses. Adverse events noted were fatigue and malaise but with no change in the graft status. Eleven of the 13 showed objective improvement in their symptoms and viral load.
Cellular Therapies Available T-Cell Expansion – IE-1 and pp65 proteins are two of the most immunogenic CMV antigens used by APCs to stimulate T cell activation and proliferation and have been widely used to stimulate the CMV-specific immune response. In the earlier studies, CMV-specific CD8+ T-cell clones were produced by stimulating donor mononuclear cells obtained from peripheral blood (PBMC) with CMV-infected fibroblasts. Unfortunately, this resulted in recipient infection and had to be discontinued. Subsequently, CMV-specific T cell production was achieved through stimulation by lysates or pp65-NLV peptide. But the resultant T cell generated had limited usage as it was specific for only a viral epitope, thus limiting the utility. However, by using “poly-specific” products targeting multiple antigens this problem was resolved and T cells were generated by incubating allogeneic T-cells in vitro with clusters of 15-mer peptides spanning the entire pp65 antigen to generate CMV-specific oligoclonal T-cells. Adoptive transfer of this oligoclonal T-cells led to elimination of viremia with a lasting presence of over 2 years in circulation. Improvements in the technique over time have reduce alloimmune response activation.
Direct Selection Using Specific Peptide–MHC (pMHC) – Use of specific peptide MHC to bind the T cell receptor and stimulate T cell production by applying the knowledge of immunogenicity of IE-1 and pp65. This method is limited by its ability to produce only CD4+ and CD8+ T cell population. Also, the irreversibilty of the binding to the T cell receptor can cause pMHC multimers allows to isolate T-cells based on the T-cells receptor (TCR) can cause functional alteration such as internalization, activation, overstimulation and death. The Streptamer technology has been used to solve this problem. It is able to reverse the peptide-T – cell receptor binding. The peptide competes with the Streptamer and causes its monomerization and preventing functional alteration of the T- cell receptor.
Direct Selection Using Cytokine Capture System (CCS) –Use ofIFN-γ cytokine capture system (CCS) to select CMV-specific T-cells. Viral antigens are used to stimulate CD4+ and CD8+ INF-γ secreting T-cells that not restricted to a specific HLA. Based on expression of certain molecules such as CD25, CD69, CD137 and CD154 which are seen after T cell activation, virus specific T cells can be isolated and enriched for production and use.
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
This successful therapy in cancer treatment entails the genetic modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR) leading to the generation of autologous CAR T-cells. It has now been explored as immunotherapy against CMV by enabling antigen recognition in a MHC independent manner. This can be tailored to specifically target conserved and essential epitopes of the selected antigen, overcoming pathogen escape mechanisms.
Cell Therapy Limitations and Alternatives in SOT Patients Long term survival of transfused T cells is affected by the prolonged immunosuppression that affects T cell differentiation and its antiviral properties. Additionally, in vitro generated T cells are sensitive to immunosuppressive medications which further impairs their ability to produce cytokines for proliferation. Genetically modified T cells that will be resistant to these drugs is a possible solution to this problem. Alternatively, reducing patient´s immunosuppression after T cell infusion may allow the expansion and functionality of the CMV-specific T-cells. Moreover, T cell infusion can trigger alloimmune activation and graft rejection, this can be curtailed by culturing T cell clones that will eradicate alloreactive T cells.
Future Directions and PerspectivesAdoptive T cell transfer could be the cornerstone of treatment of drug resistant CMV infection but there are several limitations to isolating and using these cells. To solve this problem, the use of third-party CMV-specific T-cell banks to ensure the availability of well characterized the T-cell products is necessary. Additionally, we need better results on studies using T-cell adoptive immunotherapy in SOT recipients that had optimal clinical outcomes.
Is It Feasible to Use CMV-Specific T-Cell Adoptive Transfer as Treatment Against Infection in SOT Recipients?
Summary of this article:
Viral infection, including cytomegalovirus (CMV), BK virus, and Epstein-Barr virus,
remains a significant cause of morbidity and mortality in immunocompromised
individuals. While in immunocompetent individuals, latent CMV infection is controlled by
the immune system.
The incidence of CMV reactivation/reinfection in SOT is 16–56%
A cell-mediated immune response is considered the most critical arm of the immune
system against CMV infection.
CMV infection after transplantation is common; around one third of patients receiving
organ may develop CMV infection CMV infection can affect the outcome of SOT through various mechanisms:
CMV may infect the graft and cause graft dysfunction Reduction of immunosuppression
may predispose to rejection The use of antiviral is associated with side effects The principleof adoptive immunotherapy in treatment of CMV infection after
transplantation is using CMV specific cytotoxic T lymphocytes (ex vivo T-cell culture) or
donor lymphocyte infusion to kill CMV infected cells. The transfer of CMV-specific T-cell is widely used in Hematopoietic Stem Cell Transplant
(HSCT) patients; on the other hand it is less studied in the settings of organ
transplantation which may be explained by the rule of immunosuppression which may
attenuate T cell response, moreover, infusion of donor lymphocytes may cause immune
response and graft versus host disease Side effects of adoptive immunotherapy:
-Graft Versus Host Disease (GVHD) which is less common if using CMV specific cytotoxic T lymphocytes, and very common when using donor derived lymphocytes -Allergic reactions -Flue like symptoms Cellular therapy available for generation of CMV specific T-cells:
– T-cell expansion
– Direct selection using specific peptide – MHC (pMHC)
– Direct selection using cytokine capture (CCS)
– T-Cell Generation Using Activation Markerand Engineered T-Cells (CAR, TCR) Cell Therapy Limitations and alternatives in SOT Patients:
The main limitation for the use of cellular therapy is the use of long term
immunosuppression that can affect the long term survival of transfused T cells, this can
be managed by reduction of immunosuppression once the cells are transfused and to
genetically modify the in vitro generated cytotoxic T cell to allow for resistance to the
immunosuppressive drugs. The role of Adoptive immunotherapy in managing different conditions related to transplantation: – Treatment of resistant and refractory cases of EBV+ PTLD cases – May be used for the treatment of acute rejection through infusing Treg cells – Treatment of resistant cases of CMV, BKN.
Conclusion: -The use of T-cell adoptive therapy may help to restore the CMV-specific immunity for
preventing CMV infection in SOT individuals who do not respond to conventional
therapies, such as patients infected with antiviral resistant strains
-Recent studies have significantly increased our knowledge about the protective role of
CMV-specific T-cell immune response against CMV infection and disease
– Further work is clearly needed in order to fully understand and assess the clinical utility
Is-It-Feasible-to-Use-CMV-Specific-T-Cell-Adoptive-Transfer-as-Treatment-Against-Infection-in-SOT-Recipients? INTRODUCTION:
Viral infections especially cytomegalovirus (CMV), BK virus and Epstein-Barr virus, are commonest complications of organ transplant and HSCT and lead to increase risk of morbidity and mortality.
CMV infection post transplant carry high risk of recurrent infections especially in seronegative recipients received a graft from a seropositive donor (R-/D+), HIV patients, and patients who have received T-cell depletion therapies (alemtuzumab, antithymocyte globulin, or post-transplant cyclophosphamide.
The incidence of CMV reactivation/reinfection in SOT is 16–56%.
Clinical manifestations of CMV infection can cause gastroenteritis, pneumonitis, hepatitis, uveitis, retinitis, encephalitis and graft rejection mainly due to direct effects of CMV proliferation.
This study focus on the role of CMV-specific T-cells in protecting from infection, which may improve clinical care after transplantation.
USE OF ADOPTIVE TRANSFER OF CMV- SPECIFIC T-CELLS IN THE CONTEXT OF SOLID ORGAN TRANSPLANTATION:
CMV-specific T-cell adoptive transfer is promising to use in treatment of CMV infection and disease in ulcerative enteritis in primary immunodeficiency or in pediatric retinitis caused by CMV.
CMV-specific T-cell transfer used in cases of Hematopoietic Stem Cell Transplant (HSCT) patients as a protective antiviral immunity, and as a treatment in patients with refractory CMV infection.
However there is still limited data on using for treatment CMV in organ transplant.
But there’s studies on case with persistent CMV viremia resist to ganciclovir and pneumonia post lung transplant, where treated with two infusions of 1 × 107/m2 CMV‐specific T-cells and shows improvement of clinical situations and decrease CMV viremia with increase of the CMV- specific T-cell levels. Unfortunately patients died because of graft failure.
Since use T-cell adoptive transfer as a therapy in SOT recipients in refractory CMV lead to fifty fold decreased of the CMV DNA viral load.
Also used in treatment of Thrombotic thrombocytopenia purpura with successful outcome .
transferring allogeneic CMV-specific T lymphocytes on CMV infection or reactivation. This therapy promised to treat CMV infection and CMV disease in organ transplant. but it’s side effects is fatigue and malaise. It’s very effective in reduce CMV viremia and disease and increase T cell.
In many studies shows improvement in clinical syndrome of CMV infection and absence of CMV antigen and always death in organ transplant with CMV infection dia from other complications rather than CMV infection.
CELLULAR THERAPIES:
T-Cell Expansion:
This method used to generate T cell expansion
There are different approaches used for T cell in vivo expansion.
First approach// T cell expansion is generated by stimulating donor peripheral blood mononuclear cells (PBMC) with CMV-infected fibroblasts. but this approach may induce infection in patients. So this approach no more use.
Other approach is CMV lysates or pp65-NLV peptide were used to stimulate CMV-specific T-cells.
The main action is to stimulate adoptive immunity against a single viral epitope.
It’s action to eliminate viremia.
Direct Selection Using Specific Peptide–MHC (pMHC):
It’s for HLA typing only. This method used to isolate only CD8+ or CD4 T-cell.
This method allows to reduce the time and improve the quality of the final product, less alloreactivity. it’s designed for alteration of T cell function. Due to use of immunosuppressive drug leading deficiencies in T-cell differentiation and affects longterm survival of the transplanted cells limiting its use for adoptive therapy. but still use in treat CMV infection. It’s still under search. Direct Selection Using Cytokine Capture System (CCS): T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR): Cell Therapy Limitations and Alternatives in SOT Patients:
Due to use of immunosuppressive therapy which reduce T cell proliferation and function and also long term use of CMV eradication therapy which are nephrotoxic and development of drug resistance to CMV virus; all of these factors predispose patients to develop CMV viremia and disease, So cell therapy may be an appropriate and effective alternative antiviral treatment.
Also due to T cell depletion with use of immunosuppressive drug ; so should be reduce dose of immunosuppressive drug to allow the expansion and functionality of the CMV-specific T-cells.
third-party T-cells to infuse a kidney transplant patient who had ganciclovir resistant persistent CMV viremia, and decreased the levels of immunosuppressive drugs. This shows significant decrease of CMV DNA viral load within 4 months post infusion and continuous controlled up-to 1 year.
use of T-cell adoptive therapy may help to restore the CMV- specific T cell.
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
In treatment of PTLD post EBV/ BK virus
In treatment of GVHT
In Case of antiviral resistance
INTRODUCTION
· In immunocompromised people, viral infections such as (CMV), BK virus, and Epstein-Barr virus continue to be a major source of morbidity and mortality.
· CMV infection is one of the main infectious problems in transplant recipients, both for hematopoietic stem cell (HSCT) and solid organ transplantation (SOT).
· In addition to the clinical signs of the viral syndrome caused by CMV proliferation, which has direct effects, CMV infection can also result in a higher incidence of graft rejection, opportunistic infections, or a lower recipient survival rate.
· As more evidence suggests that CMV-specific T-cells play a role in infection protection, the immune system’s cell-mediated response is seen as the most crucial defense against CMV infection.
· Strong attempts have been undertaken to look for alternative therapeutic options due to problems with the new anti-CMV medications such as toxicity, cost, and resistance.
USE OF ADOPTIVE TRANSFER OF CMV- SPECIFIC T-CELLS IN THE CONTEXT OF SOLID ORGAN TRANSPLANTATION
· Contrary to its widespread investigation and use in hematopoietic stem cell transplant recipients and its use as a treatment for CMV infection in current applications like ulcerative enteritis in primary immunodeficiency or in pediatric retinitis caused by CMV, it has received less research in SOT recipients. This is likely because the immunosuppressive therapy’s administration attenuates the T-cell response.
· In addition, donor-derived cytolytic T lymphocytes (CTLs) may not be tolerated by SOT recipients because they directly stimulate alloreactive T-cells, causing alloimmune damage.
CELLULAR THERAPIES AVAILABLE T-Cell Expansion
· T-cells that are specific to CMV were stimulated with CMV lysates or the pp65-NLV peptide. Adoptive immunity was solely activated by the pp65-NLV peptide against a specific viral epitope.
· The oligoclonal T-cell adoption was successful in eliminating viremia, and the infused cells survived for up to two years. Direct Selection Using Specific Peptide–MHC (pMHC)
· The capacity of the T-cell receptor (TCR) to bind a complex combination of peptide-loaded recombinant HLA molecules enables the isolation of T-cells using pMHC multimers.
· This technique minimizes alloreactivity while cutting down on time and improving the quality of the end result.
· The method’s restriction to isolating just CD8+ or CD4 T-cell populations, as well as the binding’s irreversibility, which might result in alterations to the T-cell phenotypic, are its principal drawbacks. Direct Selection Using Cytokine Capture System (CCS)
· A rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral.
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
· Adding tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors to a patient’s lymphocytes is another intriguing strategy based on the effectiveness of cancer treatment (CAR).
CONCLUSIONS
· Our understanding of the protective function of the CMV-specific T-cell immune response against CMV infection and illness has considerably increased as a result of studies conducted.
· T-cell adoptive therapy may be used as a treatment for CMV infections in SOT individuals who do not respond to conventional therapies, such as patients infected with antiviral-resistant strains that have no other available options, in addition to helping to restore the CMV-specific immunity for preventing CMV infection.
· The use of CMV-specific adoptive transfer as an alternate therapy for SOT recipients may be aided by recent findings. However, to evaluate the therapeutic effectiveness of these approaches in SOT recipients, more research is required.
======================================================== Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
· Recurrent leukemia after allogeneic bone marrow transplantation.
· Treatment against CMV infection in SOT recipients.
· Treatment of PTLD caused by Epstein–Barr virus.
Viral infection, including cytomegalovirus (CMV), BK virus, and Epstein-Barr virus, remains a significant cause of morbidity and mortality in immunocompromised individuals. While in immunocompetent individuals, latent CMV infection is controlled by the immune system. The incidence of CMV reactivation/reinfection in SOT is 16–56%
A cell-mediated immune response is considered the most critical arm of the immune system against CMV infection.
USE OF ADOPTIVE TRANSFER OF CMV-SPECIFIC T-CELLS IN THE CONTEXT OF SOLID ORGAN TRANSPLANTATION:
CMV-specific T-cell adoptive transfer is currently being evaluated for clinical application, with promising results as a treatment for CMV infection and disease in ulcerative enteritis in primary immunodeficiency or pediatric retinitis caused by CMV.
Several clinical studies are currently conducted:
(i) A clinical trial (NCT03665675) including 20 HSCT and SOT recipients patients is conducted to study the effect of transferring allogeneic CMV-specific T lymphocytes on CMV infection or reactivation. The first results will be available at the end of 2021
(ii) A clinical trial (NCT02779439) with 25 patients enrolled to elucidate the biological efficacy of therapeutically administered most closely HLA-matched third-party donor-derived specific cytotoxic T lymphocytes (CTLs) targeting CMV, following allogeneic blood or marrow stem cell or SOT
(iii) A clinical trial (NCT04364178) including 25 patients assessing whether partially matched, ≥2/6 HLA-matched, viral-specific T-cells have efficacy against CMV in subjects who have previously received any allogeneic HSCT or SOT.
(iv) A clinical trial (NCT03266640) with 20 participants investigating the therapeutic role of CMV CTLs in children, adolescents, and young adults (CAYA) with refractory CMV infection post allogeneic HSCT or SOT
CELLULAR THERAPIES AVAILABLE:
During the last years, a better understanding of CMV-specific T-cell immunology, such as the conserved T-cell epitopes
has led to the improvement of the methods for ex vivo T-cell culture
In addition, rapid tests to evaluate the effector function of the CMV-specific T-cells have become available
T-Cell Expansion:
To expand CMV-specific T-cells, it is crucial to define the most immunogenic epitopes used by the antigen-presenting cells (APC) to promote the activation and proliferation of peptide-specific T-cells.
Direct Selection Using Specific Peptide–MHC (pMHC):
Using pMHC multimers allows isolating of T-cells based on the T cells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules
Direct Selection Using Cytokine Capture System (CCS) :
CMV-specific T-cells can also be selected using IFN-g cytokine capture system (CCS), a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral antigens
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR):
This is the gene modification of a patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR). The generation of autologous CAR T-cells, which has also been explored as immunotherapy against CMV
Cell Therapy Limitations and Alternatives in SOT Patients:
The intensity and long-term immunosuppression requirement to prevent allograft rejection predisposes SOT recipients to a wide range of viral complications.
CONCLUSIONS :
Recent studies have significantly increased our knowledge about the protective role of CMV-specific T-cell immune response against CMV infection and disease
1- Summary: Introduction:
During the last decade, many studies have demonstrated the role of CMV specific T-cell immune response on controlling CMV replication and dissemination. In fact, it is well established that transplanted patients lacking CMV-specific T-cell immunity have an increased occurrence of CMV replication episodes and CMV-related complications. In this context, the use of adoptive transfer of CMV-specific T-cells has been widely investigated and applied to Hematopoietic Stem Cell Transplant patients and may be useful as a therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia in patients receiving transplantation. However, only few authors have explored the use of T-cell adoptive transfer in SOT recipients. Use of adoptive CMV- specific T cell therapy in SOT:
Four available studies have explored the use of T-cell adoptive transfer in SOT recipients. They included a very small number of patients. One study with promising results included 13 patients with CMV resistant to anti-viral drugs. And number of infusion ranged from 1- 6 infusions.
None reported major adverse events. They reported reduction of the viral load. Only one patients was reported to have lung graft failure and death from graft failure.
Together these results suggest that, although there is still space for improvement, the use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment.
Methods used to produce CMV-specific T cells: 1- T cell expansion:
It depends on defining the most immunogenic epitopes used by the antigen presenting cells (APC) to promote the activation and proliferation of peptide-specific T-cells. IE-1 and pp65 proteins are two of the most immunodominant CMV antigens and have been widely used to stimulate the CMV-specific immune response. Ex-vivo approach is preferred.
2- Direct Selection Using Specific Peptide–MHC (pMHC)
It allows isolating T-cells based on the T cells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules. HLA peptide tetramers from pp65 and IE-1 proteins have been previously used to select CD8+ T-cells that were further isolated using magnetic beads. 3- Direct Selection Using Cytokine Capture System (CCS)
– CMV-specific T-cells can also be selected using IFN-gamma cytokine capture system (CCS), a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral antigens.
– Different authors have successfully isolated functional CMV-specific T-cells using this method. 4- T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR) – Other interesting strategie is the gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR). – The generation of autologous CAR T-cells enables antigen recognition in a MHC independent manner and can be designed to specifically target conserved and essential epitopes of the selected antigen and overcoming pathogen escape mechanisms.
– While CAR-T-cell therapy identifies exclusively antigens located in the cell surface, TCR can also recognize intracellular antigenic fragments presented by MHC molecules.
– Further clinical studies will be necessary to demonstrate in vivo efficacy.
Limitations of cell therapy in SOT: 1- The deficiencies in T-cell differentiation and lifelong immunosuppression can affect to long-term survival of the transfused cells, interfering in the antiviral effect. 2- Some reported that in vitro generated CMV -specific CTL are highly sensitive to immunosuppressive drugs (such ascyclosporin A and FK506) impairing the production of effector cytokines. 3- Infusion of donor derive T-cells from donors may also transfer alloreactive T cells in numbers sufficient that could trigger episodes of rejection, particularly if the donor and the host differ in one or more HLA alleles
Over the past years third party donor T-cell banks have been established. Such banks permit selection of T-cells on the basis of HLA allele phenotype, viral specificity and HLA restriction, which may provide distinct advantages, particularly in the treatment of HLA non-identical recipients. Although it is still under study, the obtained results to date are highly promising
Conclusions:
– The role of CMV-specific T-cell immune reconstitution after SOT have demonstrated several benefits, including lower risk of CMV infection and graft rejection. Thus, the development and improvement of new CMV-specific T-cell transfer based therapies could be a useful to adjust the therapeutic interventions.
– Few studies are available which incorporated small number of patients with SOT who failed to respond to previous anti-viral medications. Although promising results were obtained, further development has been limited by due to difficulties of T cell expansion in SOT that are receiving immunosuppressive regimens, and the risk of graft rejection after T-cell administration.
– One possible approach to overcome these limitations is generating ready to use third-party CMV-specific T-cell banks to ensure the availability of well characterized the T-cell products
– Further work is clearly needed in order to fully understand and assess the clinical utility of these techniques in SOT recipients.
II- other roles of adoptive therapy in transplantation:
Introduction:
Viral infections caused by CMV, BKV, EBV and other virus lead to significant morbidity and mortality post transplant. Due to the suppression of the recipients immunity, the viruses are no longer held in check and can lead diseases or malignancies caused by these viruses. T cell immunity, which is the main target of the current immunosuppressive regimens, is affected and hence, predisposes to these viral infections.
CMV can affect multiple organs in the body and can also increase the risk of acute rejection.
There are specific CMV T cells that can control the infection and some authors have recommended to monitor these T cells for surveillance
Antiviral therapy has been used as prophylaxis and treatment of CMV disease but cases of resistance has been emerging and their use is also limited by their side effects
Use of Adoptive Transfer Of CMV Specific T Cells In SOT:
The use of CMV specific T cell adoptive transfer is currently being evaluated for clinical application in treatment of CMV infections in primary immunodeficiency with promising results.
In the context of transplantation, this therapy has been mainly investigated and applied to HSCT patients, both prophylactically, to reconstitute protective antiviral immunity, and as a treatment in patients with refractory CMV infection.
Few authors have explored the use of T cell adoptive transfer therapy in SOT patients. These studies have shown beneficial effects of this therapy when used in SOT recipients with CMV infections who had resistance to conventional therapies. Unfortunately these studies had very small numbers.
Currently, a number of clinical studies are being conducted to evaluate the efficacy and safety of this therapy.
Cellular Therapies
There are several methods to available to generate CMV specific T cells: T-Cell Expansion:
To expand CMV specific T cells, its important to define the most immunogenic epitopes used by the APCs to promote the activation and proliferation of peptide-specific T cells. Currently, the ex vivo expansion method is used which reduces the presence of alloreactive or naive T cells in the final product. In addition, T cell ex vivo stimulation and expansion requires a small blood volume to establish the T cell culture.
Direct Selection Using Peptide-Specific -MHC (pMHC):
Using pMHC multimers allows to isolate T cells based on the TCR ability to bind a complex mixture of of peptide loaded recombinant HLA molecules. HLA peptide tetramers from pp-65 and IE-1 proteins have been used to used to select CD8+ T cells that were further isolated using magnetic beads. This method allows to reduce the time and improve the quality of the final product, minimizing alloreactivity.
Direct Selection Using Cytokine Capture System (CCS):
CMV specific T cells can be selected using IFN gamma cytokine capture system, a rapid assay that allows to select and enrich CD8+ and CD4+ INF gamma secreting T cells that have been previously stimulated using viral antigens. This strategy allows T cell selection thats in contrast with pMHC has no HLA restriction and as an additional benefit, stimulating and capturing a polyclonal population of CD4+ and/or CD8+ T cells depending on the Ag used for stimulation, using the streptamer strategy
T Cell generation Using Activation Marker And Engineered T Cells (CAR, TCR):
Other interesting strategies based on the successful performance for cancer treatment is the gene modification of the patients lymphocytes with tumor-specific T cell receptors (TCRs) or chimeric antigen receptors (CARs). The generation of autologous CAR T cells has which has also been explored as immunotherapy against CMV enables Ag recognition in a MHC independent manner and can be designed to specifically target conserved and essential epitopes of the selected Ag overcoming pathogen escape mechanisms
The other TCR strategy uses heterodimers integrated by alpha and beta peptide chains to recognize specific polypeptide fragments presented by MHC complexes. While CAR T cell therapy identifies exclusively antigens located in the cell surface, TCR can also recognize intracellular antigenic fragments presented by MHC molecules.
Cell Therapy Limitations And Alternatives In SOT:
Deficiencies in T cell differentiation and lifelong ISS can affect long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipients.
Different authors have demonstrated that in vitro generated CMV specific T cells are highly sensitive to the CNIs used impairing their effectiveness. A possible solution is to genetically modify the in vitro generated cells to confer resistance to these drugs. Alternatively, one can reduce the ISS drugs during the treatment with the adoptive therapy
Another limitation is associated with deficiencies of T cell differentiation in SOT recipients receiving ISS.
The other limitation is the risk of transfer of alloreactive T cells in numbers that could trigger rejection
The creation of third party cell banks as well as third party donor registries has emerged as a new possibility of treatment that employs T cells derived from partially HLA-matched third party donors
Conclusions:
Recent studies have significantly increased our knowledge about the protective role of CMV specific T cell immune response against CMV infection and disease. Thus, the use of T cell adoptive therapy may help to restore the CMV specific immunity for preventing and treating CMV infection in SOT individuals who don’t respond to the antiviral therapies or cant tolerate the antiviral therapies
CMV infection is one of the viruses that remains a major cause of morbidity and mortality in immunocopmromised patients. The incidence of CMV activationin in SOT is having a median value of 30%..
CMV infection in addition of causing the direct effect due to its tissue proliferation and invasion, it can indirectly cause increased incidence of graft rejection and opportunistic infections or decrease recepient survival. T cell mediated immune response is the most defence against against CMV infection. There is increasing role of CMV specific- T cells in the defence against infection.
The use of available antiviral therapy are associated with some concerns related to the side effects and the emergence of resistance. Hence there is strong effort to search for new therapeutic options
Use of adoptive transfer of CMV- specific T- Cell in SOT:
This is well investigated and applied in HSCT patients but not in SOT.
Few studies have explored the use of T- cell adoptive transfer in SOT during the last decade but the results are promising. Based on this several clinical studies are nowb being conducted.
The results suggest that this approach is promising and there is still space for development in SOT.
Methodologies to generate CMV -specific T- cell
T cell expansion
Direct selection using specific peptide-MCH
Direct selection using Cytokine capture system
T- cell generation using activation marker and engeneredbT- cells
Limitations and alternatives in SOT:
The use of long term IS drugs in SOT can interfere with with the long term survival of the transfused cells
SOT recepient may not tolerate donor- derived cytolytic T lymphocytes due to the activationin of Cytokine- mediated stimulation of alloreactive T- cels causing Direct autoimmune injury
The risk of graft rejection after T- cell administration
Alternative is the generation of third party donor bank and registries as it can employs T- cell derived from partially HLA matched third part donor. This will allow to for ‘of the shelf” product. I also offers targeting multiple viral epitopes rather than monospecific approach,this carries the potentiality of increasing the antiviral effect. Conclusion
Recent studies highlighted that the use of T- cell adoptive therapy may help to restore the CMV – specific immunity for preventing and treating CMV infections in SOT individuals who don’t respond to antiviral therapy. However further work is needed to asses the clincal utility of this therapy in SOT. The role of adoptive immunotherapy in the manegemntvof different conditions related to transplantion:
It has a well stablished use after HSCT.
Its use in treatment of CMV infection and disease in SOT is promising. It is specifically needed in cases of gancclovir resistant cases.
The same applies to EBV, EBV related PTLD,BKV.
It can also be useful in the treatment of AR
It can provide a personalised medicine for the management of CMV infection after SOT
Summary of the article Is It Feasible to Use CMV-Specific T-Cell Adoptive Transfer as Treatment Against Infection in SOT Recipients?
This review article is about the impact of using CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients. Adoptive transfer of the oligoclonal T-cells were able to eliminate viremia, and infused cells persisted for up to two years
Strategies for the generation of CMV-specific T-cells.
A. Ex vivo T-cell expansion requires the in vitro stimulation and expansion of T-cells using APCs presenting viral peptides or proteins.
B. Direct selection employs virus-derived peptide specific multimers in the setting of a HLA class-I molecule, viral antigen T-cell stimulation followed by cytokine expressing T-cell selection using antibody coated immunomagnetic beads or activation marker selection based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation.
C. Genetic manipulation requires gene transfer of high affinity CMV-specific T-cell receptors (TCR) or chimeric-antigen receptors (CAR) to change specificity of T-cells to CMV antigens. The methodology for cellular therapy A. T-cell ex vivo stimulation and expansion: requires a small blood volume to establish the T-cell culture, making possible the generation of CMV-specific T-cells from low levels of circulating T-cells and naive donor sources. B. Direct Selection Using Specific Peptide–MHC (pMHC)
Using pMHC multimers allows to isolate T-cells based on the T- cells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules. C. Direct Selection Using Cytokine Capture System (CCS)
1) Using IFN- CCS, that allows to select and enrich CD8+ and CD4+ INF- secreting T-cells that have been previously stimulated using viral antigens.
2) Antigen stimulation based on the detection of specific surface molecules such as CD25, CD69, CD137 and CD154.
D. T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
Strategies based on the gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR).
1) TCR strategy uses heterodimers integrated by alpha and beta peptide chains to recognize specific polypeptide fragments presented by MHC complexes.
2) The generation of autologous CAR T-cells enables antigen recognition in a MHC independent manner and can be designed to specifically target conserved and essential epitopes of the selected antigen.
Cell Therapy Limitations and Alternatives in SOT Patients
a) in vitro generated CMV -specific CTL are highly sensitive to immunosuppressive drugs (such as cyclosporin A and FK506) impairing the production of effector cytokines.A possible solution in order to overcome this problem, is to:
1) genetically modify the in vitro generated CTL to confer resistance to these drugs.
2) decreasing patient ́s immunosuppression during a period post-infusion.
b) Deficiencies of T-cell differentiation in SOT recipients receiving immunosuppression.
The role of Adoptive immunotherapy in managing different conditions related to transplantation. 1. Adoptive immunotherapy is an attractive strategy not only to enhance antitumor responses but also to prevent GVHD and treat viral infections. 2. Immunotherapeutic strategy has been extended for multiple pathogens including cytomegalovirus, Epstein-Barr virus, adenovirus and BK polyoma-virus. 3. Has been used for relapses after allogeneic bone marrow transplantation. 4. Has been used to mediate response of established solid tumors. 5. Has been used for therapeutic benefit for renal cell carcinoma, melanoma, lung cancer, and breast cancer. 6. Treatment of EBV associated PTLD. 7. Treatment of Ganciclovir resistant CMV infection. 8. Host-directed strategies for treatment of tuberculosis.
Introduction
● Viral infection (CMV , BK , EBV) remains a major cause of morbidity and mortality in immunocompromised individuals
● The risk of CMV recurrent infections increases in :
☆ CMV seropositive allogeneic HSCT patients
☆ CMV seronegative SOT recipients from a seropositive donor
☆ HIV patients
☆ Patients who have received T-cell depletion therapy
● The incidence of CMV reactivation/reinfection is 30% in SOT and 37 % in HSCT
USE OF ADOPTIVE TRANSFER OF CMV-SPECIFIC T-CELLS IN THE CONTEXT OF SOLID ORGAN TRANSPLANTATION
● In SOT recipients
☆ T-cell response attenuation by IS drug
☆ (CTLs) activate alloreactive T-cells causing direct alloimmune injury
● Results suggest that use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment.
CELLULAR THERAPIES AVAILABLE
☆ conserved T-cell epitopes improve methods for ex vivo T-cell culture
☆ Rapid tests to evaluate the effector function of the CMV-specific T-cells have become available
☆ Methodologies available to generate CMV specific T-cells
● T-Cell Expansion
▪︎ IE-1 and pp65 proteins are the most
immunodominant CMV antigens used to stimulate the CMV-specific immune response
▪︎CMV-specific CD8+ T-cell clones were generated by stimulating donor (PBMC) with CMV-infected fibroblasts but it has risk of producing infection in patients. ▪︎poly-specific products targeting multiple antigens were generated
▪︎Recent T-cellex vivo stimulation and expansion has reduced the presence of alloreactive or naive T-cells in the final product and requires a small blood volume with low levels of circulating T-cells and naive donor sources
● Direct Selection Using Specific
Peptide–MHC (pMHC)
▪︎It need a previous knowledge about the immunodominance of the epitopes as pp65 and IE-1 proteins
▪︎This method :
• Reduce the time
• Improve the quality of the final product
• Minimizing alloreactivity
▪︎The disadvantages :
• limitation methods to isolate only CD8+ or CD4 T-cell populations
• The irreversibility of the binding can cause changes in the T-cell phenotype, leading to functional alterations of the purified T-cell population
▪︎ Streptamer technology in which there is no alteration of the phenotype or the functional status of the T-cells
Direct Selection Using Cytokine Capture
System (CCS)
▪︎This strategy has no HLA restriction and stimulating and capturing a polyclonal population of CD4+ and/or CD8+ T-cells depending on the antigen used for stimulation, not Streptamer strategy. ▪︎Isolation activated viral-specific T-cells based on specific surface molecules strongly up-regulated after T-cell activation such as CD25, CD69, CD137 and CD154
Cell Therapy Limitations and Alternatives
in SOT Patients
● Cell therapy may be an appropriate and effective alternative antiviral treatment.
● Genetically modify in vitro generated CTL to confer resistance to drugs
● Donor T-cell banks permit selection of T-cells on the basis of HLA allele phenotype, viral specificity and HLA restriction
FUTURE DIRECTIONS AND PERSPECTIVES
● Most informations available about adoptive CMV specific T-cell transfer
comes from HSCT recipients and Only few number of SOT recipients have used T-cell adoptive immunotherapy as a treatment of CMV infection or disease .
● SOT recipients enrolled previously failed to conventional treatment, with low survival rate.
● Development have been limited due to difficulties of T-cell expansion in SOT that are receiving immunosuppressive regimens, and the risk of graft rejection after T-cell administration.
● Approach to overcome these limitations is generating ready to use third-party CMV-specific T-cell banks to ensure the availability of well characterized the T-cell products
The role of adoptive immunotherapy in managing different conditions related to transplantation
* Prophylaxis of CMV when indicated
* Treatment CMV /Bk viremia/Disease after transplantation
* Treatment resistant CMV-disease
* Treatment of PTLD
* Treatment malignancies after transplantation
* Treatment of GVHD
* Protective role in adenovirus infection post-HSCT
Introduction: CMV infection is a major infectious complication of HSCT and SOT, increasing the risk of rejection, opportunistic infections, and recipient mortality. SOT patients’ immunological (CMV-specific T-cells) and virological states may aid clinical decisions. CMV-specific T cells prevent infection and improve transplantation care.
Cellular treatment may help SOTP recipients restore their CMV-specific T-cell response. SOT adoptive CMV-specific treatment. Used in primary immunodeficiency ulcerative enteritis, pediatric CMV-retinitis, and HSCT prophylaxis or treatment of refractory CMV infection. SOT recipients have been less studied.
Autologous CMV-specific T-cells in lung transplant recipients with severe and chronic CMV pneumonia refractory to ganciclovir and foscarnet showed promise. CMV-specific CTLs from third donors employed in KTRs (D+/R-) with refractory CMV infection resolved TMA characteristics, showing that SOT recipients may benefit from donor cell-banks.
The largest trial to date used T-cell adoptive treatment in SOT recipients (kidney, lung, and heart) with recurrent ganciclovir-resistant CMV infections. Immunological reconstitution was related with viremia control. These promising outcomes have prompted additional HSCT and SOT clinical trials.
Cellular treatments
T-Cell Expansion: Define the APC’s most immunogenic epitopes to activate and proliferate peptide-specific T-cells to generate CMV-specific T cells.
Polyspecific products stimulated CMV-specific T-cells.
Direct Selection Using Specific Peptide–MHC (pMHC) Multimers — T-cells are isolated by their receptor (TCR) ability to bind a complex variety of peptide-loaded recombinant HLA molecules, decreasing alloreactivity.
Limitation; isolate only CD8+ or CD4 T-cell populations. Irreversible binding can modify T-cell phenotypic and function. Epitope-specific tolerance is dose-dependent.
Direct Selection Using Cytokine Capture System (CCS)
Choosing CMV-specific T-cells can be created utilizing Cytokine Capture System (CCS), a fast test that selects and enriches CD8+ and CD4+ INF-g secreting T-cells challenged with viral antigens.
Benefits: activating and capturing a polyclonal population of CD4+ and/or CD8+ T-cells without HLA restriction Detecting surface chemicals that are selectively expressed or substantially up-regulated following T-cell activation is another way to separate activated viral-specific T-cells.
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR) – Gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR) can target specified antigen epitopes.
Limitation: MHC presentation.
Cell Therapy Limitations and Alternatives in SOT Patients
SOT Cell Therapy Limitations:
T-cell differentiation and lifetime IS can impair transfused cell survival, antiviral function, and SOT recipients’ adoptive treatment.
How to address these limitations.
Genetically modified CTL to resist immunosupression
T-cells may expand and function once IS decreases post-infusion.
Generate CD8+ and CD4+ T-cells with polyfunctional effector capabilities to fight CMV infection.
Third-party cell banks allow treatment with partially HLA-matched donor T-cells.
Targeting many viral epitopes instead of one, potentially enhancing antiviral efficacy.
Future perspectives
CMV adoptive treatment in SOT demonstrated encouraging results in a few restricted studies.
T-cell growth in immunosuppressed SOT and graft rejection after T-cell delivery are challenges. Third-party CMV-specific T-cell banks overcome this.
Please summarise this article. Introduction: CMV infection either by virus reactivation in the recipient, or receiving the virus from the donor, are the most common ways, this virus is controlled by the T-cells that are targeted by the immunosuppressive medications (alemuzumab, ATG, … others) in HSCT and SOT, hence the prevelnce of CMV viremia and infection, increased in these patient., that is related to high morbidity, mortality and graft loss/rejection. The treatment and prevention of the infection, have been addressed by literatures, by many antiviral therapy with side effects of neutropenia( ganciclovir), and nephrotoxicity(foscarnet and cidovovir), with some resistant strains difficult to treat. This review highlights the role of CMV T-cell infusion in prevention and treatment of CMV infection in SOT.
USE OF ADOPTIVE TRANSFER OF CMV[1]SPECIFIC T-CELLS IN THE CONTEXT OF SOLID ORGAN TRANSPLANTATION: – The effective application of CMV-specific partially HLA matched CTLs from third donors, suggesting that creating donor cell-banks could be useful as a therapeutic alternative in SOT recipients – CMV-specific T-cells were isolated and stimulated with autologous PBMCs coated with HLA class I-restricted CMV peptide epitopes, based on patient´s HLA class I typing. The in vitro expanded T-cells showed an increase in HLA epitopes (A1, B7 and B35) and in the proportion of IFN-g+ CD107a+ cells that indicates the granule-dependent (perforin/granzyme) pathway of cytotoxic CD8+ T-cells. – CMV viral load became undetectable, the patient’s usual immunosuppression regime was resumed, hepatic and bone marrow function remained normal with no evidence of acute rejection. – The most ambitious study was performed in a cohort of 21 SOT recipients (13 kidneys, 8 lungs and 1 heart) who developed recurrent ganciclovir resistant CMV infections. Thirteen of these patients (8 D+/R-, 3 D+/R+ and 2 D-/R-) were subjected to T-cell (ranging from 22.2-245 × 106 T-cells) adoptive transfer receiving a maximum of 6 doses one of which discontinued therapy after a single dose, results in control of viremia, and reduction or even stopping the antiviral therapy, with negligible side effects. CELLULAR THERAPIES AVAILABLE: 1. T-Cell Expansion: Epitopes (pp65, IE-1,.. etc) used by the antigen presenting cells (APC) to promote the activation and proliferation of CMV-peptide-specific T-cells.
PROS: requires a small blood volume to establish the T-cell culture, making possible the generation of CMV-specific T-cells from low levels of circulating T-cells and naive donor sources. CONS: only stimulated adoptive immunity against a single viral epitope, application may be limited for HLA-A2 patients/donors, and risk of producing infection later. 2. Direct Selection Using Specific Peptide–MHC (pMHC): Using pMHC multimers allows to isolate T-cells based on the T[1]cells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules.
PROS: requires less time, good quality CMVTLS, safe to treat CMV infection in SOT. CONS: isolates only CD8, or CD4 T-cells, irreversible cell binding may alter the function of the T-cells. 3. Direct Selection Using Cytokine Capture System (CCS): A rapid assay that allows to select and enrich CD8+ and CD4+ INF-gamma secreting T-cells that have been previously stimulated using viral antigens.
PROS: no HLA restrictions, rapid, CD8 and CD4 (polyclonal) cells were obtained. CONS: little clinical experience. 4. T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR): The gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR). PROS: antigen recognition in a MHC independent manner and can be designed to specifically target conserved and essential epitopes of the selected antigen, OVERCOMING pathogen escape, polyclonal cells were obtained. CONS: The very low affinity to T-cell for the pathogen antigen, further studies required. Cell Therapy Limitations and Alternatives in SOT Patients: Deficiencies in T-cell differentiation and lifelong immunosuppression can affect to long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipients., can be overcome by: · Genetically modify the in vitro generated CTL to confer resistance to IS drugs. · Reducing the IS drugs dose. · Promoting the generation of multiple polyfunctional effector functions that may be more effective in controlling CMV infection. · The creation of third-party cell banks as well as third party donor registries has emerged as a new possibility of treatment. Future direction and perspectives: · Only few reports including a small number of SOT recipients have used T-cell adoptive immunotherapy as a treatment of CMV infection or disease, mandates further large population studies. · Difficulties of T-cell expansion in SOT that are receiving immunosuppressive regimens, and the risk of graft rejection after T-cell administration. · Generating ready to use third-party CMV-specific T-cell banks to ensure the availability of well characterized the T-cell products can overcome the aforementioned limitations. Conclusions: Adoptive therapy may help to restore the CMV-specific immunity for preventing CMV infection and treating for CMV infections in SOT individuals who have antiviral resistant CMV strains, with no alternative treatment available. Generation of third party donor cell banks may help to use CMV-specific adoptive transfer as an alternative therapy for SOT recipients. Further work is needed to address the clinical utility of these techniques in SOT recipients.
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation. 1. Treatment and prevention of CMV. 2. Treatment of PTLD. 3. Treatment of BKV. 4. Treatment of acute antibody mediated rejection. 5. Treating EBV related malignancies.
Introduction:
-CMV infection is one of the main infectious complications in HSCT and SOT, it can increased risk of rejection, opportunistic infections or decreased recipient survival.
– Monitoring both immunological (CMV-specific T-cells) and virological status may facilitate clinical decisions during follow-up of SOT recipients.
– Evidences demonstrate a role of CMV-specific T-cells in protecting from infection, and improve clinical care after transplantation. Therefore, the use of cellular therapy may be useful to reconstitute the CMV specific T-cell response in SOT recipients.
Use of adoptive CMV- Specific therapy in SOT.
– Used in treatment for CMV infection and disease in ulcerative enteritis in primary immunodeficiency, pediatric CMV-retinitis, and in HSCT as prophylactic or treatment of refractory CMV infection.
– The use in in SOT recipients it has been less investigated.
– Study in lung transplant recipient with a severe and persistent CMV pneumonia resistant to ganciclovir and foscarnet used autologous CMV‐specific T-cells showed promising results.
– CMV-specific CTLs from third donors used in KTRs (D+/R-) with refractory CMV infection showed good results with resolution of TMA features, suggesting that creating donor cell-banks could be useful as a therapeutic alternative in SOT recipients.
– The most ambitious study carried out to date was performed in SOT recipients ( kidney, lung and heart) who
developed recurrent ganciclovir resistant CMV infections, T-cell adoptive therapy used and showed evidences of immunological reconstitution was associated with control of viremia.
-Based on these promising results, several clinical studies are currently been conducted in HSCT and SOT.
Cellular therapies available T-Cell Expansion
– Define the most immunogenic epitopes used by the APC to promote the activation and proliferation of peptide-specific T-cells is crucial to generate CMV-specific T cell.
– Polyspecific products targeting multiple antigens were generated to stimulate CMV- specific T-cells.
Direct Selection Using Specific Peptide–MHC (pMHC)
– Using pMHC multimers allows to isolate T-cells based on the T-cells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules
– HLA restricted, and minimizing alloreactivity.
– Limitation; isolate only CD8+ or CD4 T-cell populations, and the irreversibility of the binding can change T-cell phenotype, leading to functional alterations of T-cell population.
– It can cause epitope-specific tolerance in a dose dependent manner.
Direct Selection Using Cytokine Capture System (CCS)
– CMV-specific T-cells can produced by a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been stimulated using viral antigens
– Benefits; no HLA restriction, stimulating and capturing a polyclonal population of CD4+ and/or CD8+ T-cells
– Other selection strategy is to isolate activated viral specific T-cells based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation.
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
-Gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR), can be designed to specifically target epitopes of the selected antigen.
– Limitation : restricted to MHC presentation.
Cell Therapy Limitations and Alternatives in SOT Patients
Limitations:
Deficiencies in T-cell differentiation and lifelong IS can affect to long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipients
to overcome these issues:
– Genetic modification of generated CTL to confer resistance to these IS
– Decreasing IS during a period post-infusion may allow the expansion and functionality of T-cell.
– Promote the generation of CD8+ and CD4+ T-cells with multiple polyfunctional effector functions that may be more
effective in controlling CMV infection.
– Creation of third-party cell banks a new possibility of treatment that employs T-cells derived from partially HLA-matched donors.
– Targeting multiple viral epitopes rather than a monospecific approach, potentially increasing the antiviral effect
Future directions and perspectives;
-Few limited studies showed promising result with the use of CMV adoptive therapy in SOT.
-Challenges include difficulties of Tcell expansion in SOT that are receiving immunosuppressive regimens, and the risk of graft rejection after T-cell administration.
– Third-party CMV-specific T-cell banks can overcome this issue.
Conclusion:
The use of T-cell adoptive therapy may help to restore the CMV-specific immunity for preventing CMV infection in SOT
Different new techniques to generate CMV-specific T-cells and the possible generation of third party donor cell banks may help. Further studies is needed to assess the clinical utility of these techniques in SOT recipients.
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
– Treatment of CMV resistance infection/disease.
– Treatment and prevention of EBV+ PTLD, EBV, BK
– EBV associated malignancy
– Acute rejection
Reference:
-Catherine M. Bollard. Improving T-Cell Therapy for Epstein-Barr Virus Lymphoproliferative Disorders .Journal of Clinical Oncology . Volume 31, Issue 1
-Sadia Jahan et al.T-cell adoptive immunotherapy for BK nephropathy in renal transplantation .Transpl Infect Dis . 2020 Dec;22(6):e13399. doi: 10.1111/tid.13399 -Zang YW, Gu XD, Xiang JB, Chen ZY. Clinical application of adoptive T cell therapy in solid tumors. Med Sci Monit. 2014 Jun 10;20:953-9. doi: 10.12659/MSM.890496. PMID: 24912947; PMCID: PMC4063985.
Please summarise this article. The role of CMV specific T-cell immune response on controlling CMV replication and dissemination is quite established . Those lacking CMV-specific T-cell immunity have an increased occurrence of CMV replication. The use of adoptive immune response can be used as a therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia. This artivcle provides review of useful therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia.
Creating a T cell response
T-Cell Expansion A large number of antigens expressed at different stages during viral replication participate in the activation of both CMV-specific CD8+ and CD4+ T-cells, known to mediate the immune response CMV lysates or pp65-NLV peptide were used to stimulate CMV-specific T-cells Adoptive transfer of the oligoclonal T-cells were able to eliminate viremia, and persisted for up to two years
Direct Selection Using Specific Peptide–MHC (pMHC) This method allows to isolate T-cells based on the Tcells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules
Direct Selection Using Cytokine Capture System (CCS) CMV speicific T cell are selected using IFN-g cytokine capture system (CCS), a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR) It involves gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR)
Cell Therapy Limitations and Alternatives in SOT Patients Use of long term immune suppression Deficiencies of T-cell differentiation in SOT recipients receiving immunosuppression
Alternatives Decrease immune suppression genetic modification of in vitro CTL
Future directions and perspectives The creation of third-party cell banks as well as third party donor registries
Conclusion There is establishedrole of CMV-specific T-cell immune response against CMV infection and disease T-cell adoptive therapy may help to restore the CMV-specific immunity It is important to know and understand limitations of such treatment
Summary Introduction
Viral infections in the immunocompromised patient are a major cause of morbidity and mortality.
Highest risk of infections occur in CMV seropositive HSCT, D+/R- SOT, patients who receive T cell depleting agents, HIV infected individuals.
Risk of recurrence in SOT is at 16-56% while in HSCT is 30-70%.
CMV has both direct effects causing tissue invasive disease and indirect effects causing allograft rejection, opportunistic infections and decreased survival.
Cell mediated immunity is the corner stone to control CMV viremia.
Use in SOT
Much of the adoptive immunotherapy has been utilised in HSCT where it has been used for treatment and to reconstitute protection.
However its use in SOT is limited.
Studies done in SOT have shown that adoptive therapy can contribute to immune control in CMV infection.
Cellular therapies available
1. T cell expansion
To generate and expand CMV specific T cells its important to define the most immunogenic epitopes which are IE-1 and pp65.
With adoptive transfer of oligoclonal T cells viremia is controlled and the transfused cells persisted for upto two years.
2. Direct cell selection using specific peptide MHC.
Using pMHC multimers allows to isolate T cells based on T cells receptor ability to load a complex mixture of peptide loaded recombinant HLA molecules.
This reduces time and improves quality of product.
3. Direct selection using cytokine capture system
CMV specific T cells are selected using IFN-ᵞ cytokine capture system, this allows T cells selection without HLA restriction.
4. T cell generation using activation maker and engineered T cells
Cell therapy limitations
1. In vitro generated CMV specific CTL are highly sensitive to immunosuppression impairing production of effector cytokines.
May be addressed by decreasing the patients immunosuppression during the period post-transfusion allowing functionality and expansion of CMV specific T cells.
2. Deficiencies of T-cell differentiation in SOT receiving immunosuppression.
Can be addressed by generation of CD8 and 4 T cells displaying multiple effector functions.
3.Infusion of donor derived T cells may also transfer alloreactive cells that could trigger episodes of rejection.
This can be addressed by extensively culturing T cells to eradicate alloreactive cells.
Future directions
Role of CMV specific T cells immune reconstitution has demonstrated benefits in lowering CMV infections and incidence of graft rejection.
However most information come from HSCT with limited from SOT.
Though promising results, further development are limited by difficulties in T cell expansion and risk of rejection after administration.
This can be addressed by generation of third party CMV cell specific banks to ensure availability of well characterised products.
Conclusions
Studies have increased knowledge on protective role of CMV specific T cells on CMV disease.
T cell adoptive therapy may help prevent CMV infection and treatment in patients who don’t respond conventional therapies with no alternative treatments.
Further studies are required to further understand this therapy
Role of adaptive immunotherapy
Treatment of resistant CMV.
Prevention of CMV infection.
Prevention of GVHD in HSCT.
Treatment of EBV positive PTLD.
INTRODUCTION
Viral infection, including cytomegalovirus, BK virus and Epstein-Barr virus, remains a major cause of morbidity and mortality in immunocompromised individuals
While in immunocompetent individuals latent CMV infection is controlled by the immune system, in transplant recipients, both hematopoietic stem cell and solid organ transplantation (SOT), CMV infection is one of the main infectious complications.
CMV seropositive allogeneic HSCT patients presents the highest risk of recurrent infections, followed by CMV seronegative SOT recipients that receive a graft from a seropositive donor (R-/D+), HIV patients, and patients who have received T-cell depletion therapies. Infection in SOT recipients?
A few authors have suggested the importance of monitoring patient’s CMV-specific immunity using standardized tools for individualizing the risk of CMV infection after transplantation
Using both immunological and virological patient monitoring may provide a wider knowledge of patients’.
Strong efforts have been made to search for new therapeutic approaches. In this context, the use of cellular therapy may be useful to reconstitute the CMV specific T-cell response and to control.
We provide a synthesis of recent data regarding the impact of using CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients, the different approaches to stimulate, isolate and expand CMV-specific T-cells developed over the years and a discussion of the possible use of CMV adoptive cellular therapy in these patients Solid organ transplantation
The use of CMV-specific T-cell adoptive transfer is currently being evaluated for clinical application, with promising results as a treatment for CMV infection and disease in ulcerative enteritis in primary immunodeficiency or in pediatric retinitis caused by CMV.
After the infusion of the in vitro expanded T-cells no adverse events occurred, the CMV viral load became undetectable, the patient’s usual immunosuppression regime was resumed, hepatic and bone marrow function remained normal with no evidence of acute rejection
These results indicated that adoptive therapy can contribute to immune control of CMV infection.
The most ambitious study carried out to date was performed in a cohort of 21 SOT recipients (13 kidney, 8 lung and 1 heart) who developed recurrent ganciclovir resistant CMV infections
Thirteen of these patients (8 D+/R-, 3 D+/R+ and 2 D-/R-) were subjected to.
Together these results suggest that, there is still space for improvement, the use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment Cellular therapies available
T-cell immunology such as the conserved T-cell epitopes, has led to the improvement of the methods for ex vivo T-cell culture.
CMV-specific CD8+ T-cell clones were generated by stimulating donor peripheral blood mononuclear cells (PBMC) with CMV-infected fibroblasts.
This approach was discontinued because of the risk of producing infection in patients.
Using the pp65-NLV peptide only stimulated adoptive immunity against a single viral epitope and its application may be limited for HLA-A2 patients/donors.
To overcome this problem, “polyspecific” products targeting multiple antigens were generated by incubating allogeneic T-cells in vitro with clusters of 15-mer peptides spanning the entire pp antigen to generate CMV-.
T-cell ex vivo stimulation and expansion requires a small blood volume to establish the T-cell culture, making possible the generation of CMV-specific T-cells from low levels of circulating T-cells and naive donor sources. Direct selection using specific peptid-MHC
Cells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules.
It has been shown that pMHC multimer binding interferes with the functional status of epitope-specific T-cell population in vivo, causing epitope-specific tolerance in a dosedependent manner.
This intrinsic characteristic of pMHC multimer binding substantially limits the clinical application of this technology.
This issue has been further solved with the development of the Streptamer technology in which the binding of the HLA peptide and the antigen-specific TCR is reversed, by competing with a molecule that causes the Streptamer to monomerize, causing no alteration of the phenotype or the functional status of the T-cells.
This approach was shown to be safe to treat CMV infection in SOT patients, more research is needed. Direct selection using cytokine capture
CMV-specific T-cells can be selected using IFN-g cytokine capture system (CCS), a rapid assay that allows to select and enrich.
Other selection strategy is to isolate and enrich activated viral specific T-cells after antigen stimulation based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation, such as CD25, CD69, CD137 and CD154. Number of infusions
The patient developed a mild fever but no other adverse effects were noted and within 4 months his CMV viral load decreased from >5×10 6 copies to.
None of the patients who received adoptive CMV-specific T-cell therapy showed treatment-related grade 3, 4, or 5 adverse events.
Reduction or resolution of CMV reactivation and/or disease and improved response to antiviral drug therapy very low, which difficult the recognition.
To overcome this problem, modifications of the TCR using genetic engineering technology has been able to enhance the specificity and affinity of the recognition of the antigens by T-cells. Cell therapy limitation and alternatives in SOT patients
The intensity and long-term immunosuppression requirement to prevent allograft rejection pre-disposes SOT recipients to a wide range of viral complications
Antiviral treatment can generate side effects such as nephrotoxicity, and the selection of drug-resistant mutant CMV strains, limiting treatment capability in SOT recipients.
Based on these limitations, cell therapy may be an appropriate and effective alternative antiviral treatment. Different authors have demonstrated that in vitro generated
CMV -specific CTL are highly sensitive to immunosuppressive drugs impairing the production of effect or cytokines.
The creation of third-party cell banks as well as third party donor registries has emerged as a new possibility of treatment that employs T-cells derived from partially HLA-matched third party donors
The use of this method allows to achieve a rapid “off the shelf” product that could be used in a broader range of patients.
Over the past years third party donor T-cell banks have been established
Such banks permit selection of T-cells on the basis of HLA allele phenotype, viral specificity and HLA restriction, which may provide distinct advantages, in the treatment of HLA non-identical recipients.
It is still under study, the obtained results to date are highly promising Activation marker
Rapid detection and enrichment of T-cells; broader repertoire of antigenspecific T-cells; Compatible with other assay formats; not restricted by HLA; not needed previous information of immunodominant epitopes; no specialized APC such as dendritic cells are needed.
Time-consuming and difficulty to isolate and expand functional cells; identification of novel T-cell epitopes often requires screening of a high number of epitopes Genetically engineered
CAR-T Recognize antigens in an HLA-independent manner; target conserved and essential epitopes; infused to a broad range of patients irrespective of HLA.
Surface antigens can be targeted; restricted by epitope; expensive; Several toxicities.
TCR-T Wider range of targets; high affinity for specific antigens through genetic engineering; strong activation when a small amount of antigen is present; use of natural T-cell signaling mechanisms.
Expensive; time and labor-consuming; MHC restricted and depends on presentation by MHC molecules to recognize targets and activate T cell function; risk of hybridization between exogenous and endogenous chains
Future direction and prospective.
CMV is a major cause of severe complications in SOT recipients such as graft loss especially in patients that develop CMV infection with antiviral refractory CMV strains.
The role of CMV-specific T-cell immune reconstitution after SOT have demonstrated several benefits, including lower risk of CMV infection and graft rejection.
The development and improvement of new CMV-specific T-cell transfer based therapies could be a useful to adjust the therapeutic interventions.
Cell adoptive immunotherapy as a treatment of CMV infection or disease.
These studies enrolled SOT recipients that previously failed to conventional treatment, with low survival rate.
Better results should be obtained using T-cell adoptive immunotherapy in SOT recipients that had optimal clinical outcomes. Conclusion
Recent studies have significantly increased our knowledge about the protective role of CMV-specific T-cell immune response against CMV infection and disease.
The use of T-cell adoptive therapy may help to restore the CMV-specific immunity for preventing CMV infection in addition to serve as a treatment for CMV infections in SOT individuals who do not respond to conventional therapies, such as patients infected with antiviral resistant strains with no alternative treatment available.
Recent findings regarding the development of new techniques to select, isolate and enrich functional CMV-specific T-cells and the possible generation of third party donor cell banks may help to use CMV-specific adoptive transfer as an alternative therapy for SOT recipients.
Further work is clearly needed in order to fully understand and assess the clinical utility of these techniques in SOT recipients The role of adoptive immunotherapy;
1. Treatment of resistant case of CMV
2. PTLD, EBV, BK treatment
3. Acute rejection prevention
4. Prevention of GVHD
References
Is It Feasible to Use CMV-Specific T-Cell Adoptive Transfer as Treatment Against Infection in SOT Recipients?
Este ́ fani Garcı ́a-Rı ́os , Marcos Nue ́ valos , Francisco J. Mancebo and Pilar Pe ́ rez-Romero
Post-transplantation lymphoproliferative disorders: Current concepts and future therapeutic approaches
Fedaey Abbas, Mohsen El Kossi, Ihab Sakr Shaheen, Ajay Sharma, Ahmed Halawa
It is well known that TX recipients with impaired CMV-specific T-cell immunity are more likely to experience CMV replication episodes & consequences.
In order to reestablish the CMV specific T-cell response & control CMV viremia, the use of adoptive transfer of CMV-specific T-cells has been studied & used in HSCT patients.
Impact of CMV-specific T-cell adoptive transfer in SOT recipients:
In SOT recipients, CMV-specific T-cell adoptive transfer has been less studied possibly due to the T-cell response attenuation by the use of IS therapy.
Additionally, due to the activation of cytokine-mediated stimulation of the alloreactive T-cells generating direct alloimmune damage, SOT recipients may not tolerate donor-derived cytolytic T lymphocytes (CTLs).
The largest study to date had a cohort of 21 SOT recipients (13 kidney, 8 lung, & 1 heart) who had recurrent CMV infections with ganciclovir resistance. 13 of them (8 D+/R-, 3 D+/R+, & 2 D-/R-) underwent T-cell adoptive transfer (6 doses).
No A/Es associated with a change in the graft status occurred, & the T-cell infusion-related S/Es were of grade 1 or 2 (fatigue & malaise).
11/13 individuals displayed objective symptomatic improvement, including a decline in CMV reactivation or remission of CMV illness symptoms.
Additionally, the use of antiviral medication was either completely discontinued (in 5/11) or greatly decreased (in 6/11). Immunological reconstitution signs were related to viremia control.
Clinical trials being done in light of these encouraging results are:
(NCT03665675) trial__To investigate the impact of transplanting allogeneic CMV-specific T cells on CMV infection or reactivation, involving 20 patients, both HSCT-& SOT-recipients. The release of the initial results at end of 2021.
(NCT02779439) trial__with 25 patients enrolled aims to determine the biological efficacy of the most closely HLA-matched third-party donor-derived specific CTLs targeting CMV when administered therapeutically, in comparison to allogeneic blood or marrow stem cell or SOT.
(NCT04364178) trial__with 25 patients examines the effectiveness of partially matched, 2/6 HLA-matched, viral specific T-cells against CMV in individuals who have had any kind of allogeneic HSCT or SOT in the past.
(NCT03266640) trial___investigates the therapeutic potential of CMV CTLs in children, adolescents, & young adults with refractory CMV infection following allogeneic HSCT or SOT.
These findings show that the adoption of CMV-specific T-cell adoptive transfer is promising in SOT patients with few treatment choices for CMV infection.
Available T-cell treatments:
·In vivo expansion & generation of CMV-specific T-cells:
CMV-infected fibroblasts were used to stimulate donor PBMC to produce CMV-specific CD8+ T-cell clones. The risk of infection transmission abandoned this technique.
CMV lysates or pp65-NLV peptide to activate CMV-specific T-cells. The pp65-NLV peptide may only be useful for HLA-A2 patients & donors as it promote adoptive immunity against a specific viral epitope.
Improved ex vivo expansion methodology has reduced the presence of alloreactive or naive T-cells in the final product. This method requires a small blood volume for T-cell culture, thus allowing the generation of CMV-specific T-cells from low levels of circulating T-cells & naive donor sources.
·Direct Selection Using Specific Peptide–MHC (pMHC)
pMHC multimers are used to isolate T-cells based on the TCR ability to bind a complex mixture of peptide-loaded recombinant HLA molecules.
HLA peptide tetramers from pp65 & IE-1 proteins have been used to select CD8+ T-cells that are further isolated using magnetic beads.
This method reduces the time & improves the quality of the final product, minimizing alloreactivity.
Disadvantages:
-the method isolates only CD8+ or CD4 T-cell populations
-If the binding is irreversible, the pure T-cell population’s functional makeup may shift, changing the T-cell phenotype (such as TCR internalization, activation, overstimulation & cell death).
Streptamer technology:
Advantage_no alteration of the phenotype or the functional status of the T-cells.
Limitation_ The HLA constraint placed on the chosen T-cells by the streptamer may be a barrier to CD8+ T-cell survival in the absence of CD4+ T-cells.
To show effectiveness in SOT recipients, more research is required.
·Direct Selection Using Cytokine Capture System (CCS)
IFN-g cytokine capture system (CCS) is used to select CMV-specific T-cells.
Advantages:
-Compared to pMHC method, no HLA restriction
–Depending on the antigen utilized for stimulation, stimulating & capturing a polyclonal population of CD4+ &/or CD8+ T-cells, which is not possible utilizing the streptamer method.
The automated CliniMACS Prodigy platform:
Produces pp65-specific CTL that has functional activity.
Little clinical experience is available so far; however, this strategy may be useful for CMV-related disorders, including SOT recipients.
·T-Cell Generation Using Activation Marker & Engineered T-Cells (CAR, TCR)
The technique involves gene modification of patient’s lymphocytes with tumor-specific TCRs or chimeric antigen receptors (CAR).
Advantage of CAR-T:
Recognizes antigens without regard to HLA
Applied to a variety of patients, irrespective of HLA.
Disadvantages:
Only surface antigens can be targeted
Restricted by epitope
Expensive
Several toxicities
Advantage of TCR-T:
Wider range of targets
High affinity for specific antigens through genetic engineering
Strong activation when a small amount of antigen is present
Use of natural T-cell signaling mechanisms
Disadvantages:
Expensive
Time- & labor-consuming
MHC restricted & depends on presentation by MHC molecules to recognize targets & activate T cell function Risk of hybridization (mismatch) between exogenous & endogenous chains.
========================== 2. Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
SOT recipients are more vulnerable to a variety of viral problems because of the intense & prolonged IS. Additionally, antiviral therapy might result in A/Es such nephrotoxicity & the selection of drug-resistant mutant CMV strains, reducing the ability of SOT recipients to receive treatment.
Based on these restrictions, adoptive immunotherapy might be a suitable & efficient antiviral option. The long-term survival of the transfused cells, however, can be impacted by abnormalities in T-cell differentiation & lifelong IS, interfering with the antiviral functionality & restricting its utility for adoptive therapy in SOT recipients.
To overcome these limitations, numerous publications have shown that CMV-specific CTL produced in vitro are extremely susceptible to IS medications that inhibit the generation of effector cytokines. The in vitro generated CTL could be genetically altered to provide drug resistance as a potential remedy for this issue.
Alternately, lowering the patient’s IS in the post-infusion phase may enable the development & operation of CMV-specific T cells. Macesic et al. reduced the levels of IS medications in a KTX patient who had recurrent CMV viremia that was resistant to ganciclovir by infusing third-party T-cells into the patient. The patient’s CMVDNA viral load significantly decreased within 4 months of the transfusion & stayed under control for 1 year, resulting in the infection being cleared.
These findings suggested that third-party CMV-specific Tcells might be employed in patients who consent to a decrease in IS without endangering the stability of the allograft.
Drawbacks linked to IS-treated SOT recipients’ impaired T-cell differentiation:
The majority of research have used T-cell ex vivo stimulation to produce CMV-specific oligoclonal T-cells using the viral antigens UL123 (IE1) & UL83 (pp65), which are known to strongly stimulate a T-cellular response.
Only a few studies have examined the cell-mediated response to viral multiple antigens other than IE1 & pp65.
Therefore, efforts should be made to encourage the development of CD8+ & CD4+ T-cells with numerous polyfunctional effector roles, as these cells may be more successful in preventing CMV infection.
Infusion of donor-derived T-cells from donors may also transfer alloreactive T cells in sufficient numbers to cause episodes of rejection. This is especially true if the donor & the host have different combinations of one or more HLA alleles, as this could cause the host to become hypersensitive to particular non-self HLA alleles present on the donor T-cells. Extensive T-cell culture can be used to remove alloreactive T cells, but doing so may also cause the virus-specific T cells that were modified ex vivo to undergo replicative senescence.
A new therapy option that uses T-cells produced from partially HLA-matched third-party donors is the development of third-party donor registries & third-party cell banks. This technique permits a quick “off the shelf” product that might be used by a wider spectrum of patients.
This can also boost the antiviral efficacy by targeting numerous viral epitopes, as compared to a monospecific strategy. Third-party donor T-cell banks allow for the selection of T-cells based on viral specificity, HLA limitation, & allele phenotype, which may have significant benefits, especially when treating patients who do not have the same HLA.
Even though more research is needed, the outcomes thus far are very encouraging.
Please summarise this article. INTRODUCTION
-Viral infection, including cytomegalovirus (CMV), BK virus and Epstein-Barr virus, remains a major cause of morbidity and mortality in immunocompromised individuals .
-In transplant recipients, both HSCT and SOT, CMV infection is one of the main infectious complications.
– Direct effects of CMV proliferation causing viral syndrome and indirect effects cause increased incidence of graft rejection and opportunistic infections or decreased recipient survival .
-Cell mediated immune response is considered the most important arm of the immune system against CMV infection and CMV-specific T-cells important in protecting from infection. USE OF ADOPTIVE TRANSFER OF CMV SPECIFIC T-CELLS IN THE CONTEXT OF SOT
-In SOT, CMV-specific T-cell transfer has been widely investigated and applied to HSCT patients, both prophylactically, and as a treatment in patients with refractory CMV infection.
-Few authors have explored the use of T-cell adoptive transfer
in SOT recipients during the last decade . The results indicated that adoptive therapy can contribute to immune control of CMV infection . CELLULAR THERAPIES AVAILABLE
-During the last years a better understanding of the CMV-specific T-cell immunology such as the conserved T-cell epitopes , has led to the improvement of the methods for ex vivo T-cell culture . T-Cell Expansion
-To successfully generate and expand CMV-specific T-cells, it is
crucial to define the most immunogenic epitopes used by the
antigen presenting cells (APC) to promote the activation and
proliferation of peptide-specific T-cells .
-IE-1 and pp65 proteins are two of the most immunodominant CMV antigens and have been widely used to stimulate the CMV-specific immune response .
– In the initial studies, CMV-specific CD8+ T-cell clones were generated
by stimulating donor peripheral blood mononuclear cells (PBMC) with CMV-infected fibroblasts .
– CMV lysates or pp65-NLV peptide were used to stimulate CMV-specific T-cells .
– T-cell ex vivo stimulation and expansion requires a small blood volume to establish the T-cell culture, making possible the generation of CMV-specific T-cells from low levels of circulating T-cells and naive donor sources . Direct Selection Using Specific Peptide–MHC (pMHC)
-Using pMHC multimers allows to isolate T-cells based on the Tcells
receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules.
-This method allows to reduce the time and improve the quality of the final product, minimizing alloreactivity .
-The main disadvantages of this technique are related with the limitation of the method to isolate only CD8+ or CD4 T-cell populations, and the irreversibility of the binding that can cause changes in the T-cell phenotype.
-In the context of SOT, p-MHC multimers has been previously used using autologous T-cells harvested from lifelong immunosuppressed patients .The associated challenges of this method could be minimized by using partially HLA-matched CMV-specific T-cells obtained from a third party donor . Direct Selection Using Cytokine Capture System (CCS)
-CMV-specific T-cells can be selected using IFN-g cytokine
capture system (CCS), a rapid assay that allows to select and enrich
CD8+ and CD4+ INF-g secreting T-cells .
– Different authors have successfully isolated functional CMV-specific T-cells using this method.
-Some selection strategy is to isolate and enrich activated viral specific
T-cells after antigen stimulation based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation, such as CD25, CD69, CD137 and CD154. -Other strategies based on the successful performance for cancer treatment is the gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR). Cell Therapy Limitations and Alternatives in SOT Patients
-The intensity and long-term immunosuppression requirement to
prevent allograft rejection pre-disposes SOT recipients to a wide
range of viral complications .
-In addition, antiviral treatment can generate side effects such as nephrotoxicity , and the selection of drug-resistant mutant CMV strains , limiting treatment capability in SOT recipients.
-Different authors have demonstrated that in vitro generated
CMV -specific CTL are highly sensitive to immunosuppressive
drugs impairing the production of effector cytokines .
-Decreasing patient´s immunosuppression during a period post-infusion may allow the expansion and functionality of the CMV-specific T-cells.
-Third-party CMV-specific T cells can be used in patients that admit a reduction of the immunosuppression regimen without compromising the allograft stability.
-Another limitation is associated with deficiencies of T-cell
differentiation in SOT recipients receiving immunosuppression.
– Infusion of donor derive T-cells from donors may transfer alloreactive T cells in numbers sufficient that could trigger episodes of rejection, particularly if the donor and the host differ in one or more HLA alleles.
-The creation of third-party cell banks as well as third party donor registries has emerged as a new possibility of treatment that employs T-cells derived from partially HLA-matched third party donors . FUTURE DIRECTIONS AND PERSPECTIVES
– The role of CMV-specific T-cell immune reconstitution after SOT have demonstrated several benefits, including lower risk of CMV infection and graft rejection.
-The development and improvement of new CMV-specific T-cell transfer based therapies could be a useful to adjust the therapeutic interventions.
-Most of the information of CMV specific T-cell transfer available
comes from studies in HSCT recipients . Only few reports including a small number of SOT recipients have used Tcell adoptive immunotherapy as a treatment of CMV infection or disease .
– Better results should be obtained using T-cell adoptive immunotherapy in SOT recipients that had optimal clinical outcomes.
-Results from the ongoing clinical trial analyzing the safety and feasibility of administering CMV specific- CTLs from haploidentical donors in transplant patients would be of importance to implement
T-cell adoptive therapy in SOT recipients.
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
1.Epstein-Barr Virus Lymphoproliferative Disorders
2.Resistant case of CMV.
3.BK nephropathy post kidney transplant References
1.Catherine M. Bollard. Improving T-Cell Therapy for Epstein-Barr Virus Lymphoproliferative Disorders .Journal of Clinical Oncology . Volume 31, Issue 1
2. Sadia Jahan et al.T-cell adoptive immunotherapy for BK nephropathy in renal transplantation .Transpl Infect Dis . 2020 Dec;22(6):e13399. doi: 10.1111/tid.13399.
Summary of the Article: The Introduction: The use of cellular therapy (CMV-specific T-cell response to control CMV viremia and disease. Transplant recipients are exposed to a high risk of morbidity and mortality, due to viral infection, (BK, CMV, EBV) as their immunocompromised.
Recipients with seronegative and D+, ATG, and cyclophosphamide post-transplant are more susceptible of infection and reactivation. The incidence of CMV reactivation and reinfection is more prevalent in HSCT than in SOT, with the incidence rate of 30-70% and 16-56% respectively. Viral syndromes associated directly with CMV:
Gastroenteritis.
Pneumonitis.
Hepatitis.
Uveitis.
Retinitis.
encephalitis.
Graft rejection.
Viral and immunological monitoring provide a wider knowledge of patients’ clinical situations that may facilitate clinical decisions during follow-up. Although advances in antiviral treatment against CMV in immunosuppressed recipients, there are still undesirable unavoidable side effects. Adoptive transfer of CMV-specific T-cell in SOT:
Less investigated in SOT, due to the T-cell attenuation produced by immunosuppressive therapy.
Authors recommend the use of CMV-specific T-cell transfer in SOT (D+/R-) with CMV viremia and refractory CMV.
Brestrich et al.; use an adoptive 2 infusion of CMV-specific T-cell in lung transplants who develop CMV pneumonia; it shows overall improvement (after the first infusion) in the viral load and pneumonia symptoms and an increase in the CMV-specific T-cell level.
Pierucci et al.; use autologous T-cell transfer in R-/D+ with a ganciclovir, foscarnet resistance, and cidofovir nephrotoxicity, the patient receives 2 infusions 2 weeks apart with no side effects and low CMV titer, with viral load relapse after 2 months, a third infusion received and showing some therapeutic benefit and a further significant reduction in CMV titer.
Many clinical trials show improvement in viral load, symptoms, and a significant reduction in CMV titer, with fewer side effects.
The Strategies of adoptive immunotherapy:
Ex vivo T-cell expansion requires the in vitro stimulation and expansion of T-cells using APCs presenting viral peptides or proteins.
Direct selection employs virus-derived peptide-specific multimers in the setting of a HLA class-1 molecule, viral antigen T-cell stimulation followed by cytokine expressing T-cell selection using antibody-coated immunomagnetic beads or activation marker selection based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation.
Genetic manipulation requires gene transfer of high-affinity CMV-specific T-cell receptors or chimeric-antigen receptors to change the specificity of T-cell to CMV antigens.
The role of adoptive immunotherapy:
D+/R- in SOT.
D+/R-, Recipient with CMV infection, with refractory CMV.
ATG and use and recipient with viral load and symptomatic disease.
CMV, BK, PTLD, EBV diseases.
Refractory and severe symptomatic after CMV disease resistant to ganciclovir, foscarnet, and cidofovir.
In cases of high prediction of graft failure with reduction of IS.
This is a narrative review study (level 5) on ways to manipulate the recipient’s immune response with donor T lymphocytes with a specific stimulus for specific care, in the case of this work it would be the treatment of Cytomegalovirus.
The recipient’s inability to trigger an adequate response against CMV, either because it is a negative recipient who received a transplant from a donor previously exposed to the virus, or a positive recipient who used anti-lymphocyte drugs and reactivated the disease. Another reason is the difficulty in living with the side effects of the antiviral drugs available for CMV, there is a proposal to establish the donation of specialized T cells with a response against the virus
.
Activation of macrophages and antigen-presenting cells and stimulation of specific T cells trigger an immune response with specific epitopes leading to a better response against CMV. More complex and, consequently, more effective and specific models, such as CAR-T and TCR-T, are T cells modified by genetic engineering for a more specific effect, but at an extremely high cost.
Undoubtedly, these are very promising techniques with more effective results, minimizing the side effects of medications and immunosuppressants. Its high cost and the need for specific cell stimulation are major challenges to the popularization of this technique.
Currently, bone marrow transplantation is already successful with CAR-T cell therapies
CMV is a major cause of severe complications in SOT recipients such as graft loss especially in patients that develop CMV infection with antiviral refractory CMV strains (110, 111).
The intensity and long-term immunosuppression requirement to prevent allograft rejection pre-disposes SOT recipients to a wide range of viral complications . In addition, antiviral treatment can generate side effects such as nephrotoxicity , and the selection of drug-resistant mutant CMV strains , limiting treatment capability in SOT recipients. Based on these limitations, cell therapy may be an appropriate and effective alternative antiviral treatment.
The role of CMV-specific T-cell immune reconstitution after SOT have demonstrated several benefits, including lower risk of CMV infection and graft rejection. Thus, the development and improvement of new CMV-specific T-cell transfer based therapies could be a useful to adjust the therapeutic interventions .
Using CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients. ——————————————————————————————————-
The use of CMV-specific T-cell adoptive transfer is currently being evaluated for clinical application, with promising results as a treatment for CMV infection and disease in ulcerative enteritis in primary immunodeficiency or in pediatric retinitis caused
by CMV .
In the context of transplantation, CMV-specific T-cell transfer has been widely investigated and applied to Hematopoietic Stem Cell Transplant (HSCT) patients, both
prophylactically, to reconstitute protective antiviral immunity, and as a treatment in patients with refractory CMV infection .
In contrast, in SOT recipients it has been less investigated probably due to the T-cell response attenuation produced by the administration of the immunosuppressive
therapy. In addition, SOT recipients may not tolerate donor- derived cytolytic T lymphocytes (CTLs) due to the activation of cytokine-mediated stimulation of the alloreactive T-cells causing direct alloimmune injury .
Several clinical studies are currently been conducted:
—————————————————————————
(i) A clinical trial (NCT03665675) including 20 patients, both HSCT recipients and SOT recipients is been conducted, to study the effect of transferring allogeneic CMV-specific T lymphocytes on CMV infection or reactivation .
(ii) A clinical trial (NCT02779439) with 25 patients enrolled, to elucidate the biological efficacy of therapeutically administered most closely HLA-matched third-party donor-derived specific cytotoxic T lymphocytes (CTLs) targeting CMV, following allogeneic blood or marrow stem cell or SOT.
(iii) A clinical trial (NCT04364178) including 25 patients assessing whether partially matched, ≥2/6 HLA-matched, viral specific T-cells have efficacy against CMV in subjects who have previously received any type of allogeneic HSCT or SOT.
(iv) A clinical trial (NCT03266640) with 20 participants investigating the therapeutic role of CMV CTLs in children, adolescents and young adults (CAYA) with refractory CMV infection post allogeneic HSCT or SOT.
Together these results suggest that, although there is still space for improvement, the use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment.
. CELLULAR THERAPIES AVAILABL ; ————————————————————
1-T-Cell Expansion.
Adoptive transfer of the oligoclonal T-cells were able to eliminate viremia, and infused cells persisted for up to two years .
2- Direct Selection Using Specific Peptide–MHC (pMHC).
Using pMHC multimers allows to isolate T-cells based on the T- cells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules . This method allows to reduce the time and improve the quality of the final product, minimizing alloreactivity .
3- Direct Selection Using Cytokine Capture System (CCS).
CMV-specific T-cells can also be selected using IFN-g cytokine capture system (CCS), a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral antigens .
4- T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR).
Is based on the successful performance for cancer treatment is the gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR).
Cell Therapy Limitations and Alternatives in SOT Patients;
—————————————————————————————–
The imitations ;
————————
Deficiencies in T-cell differentiation and lifelong immunosuppression can affect to long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipients.
The alternative ;
——————————-
1-In vitro generated CMV -specific CTL are highly sensitive to immunosuppressive
drugs (such as cyclosporin A and FK506) impairing the production of effector cytokines.
2- Third-party CMV-specific T- cells could be used in patients that admit a reduction of the immunosuppression regimen without compromising the allograft stability.
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation;
—————————————————————————————-
1- Prevention and treatment of EBV+PTLD .
2- treatment BK nephropathy .
3- CMV-infection treatment.
4-Prevention of rejection in living donor kidney transplant recipients .5- malignancies including HL, T/NK lymphoma and NPC as adjunctive therapy to chemotherapy and/or in relapsed patients .
CMV is common viral infection with potential devastating consequences in immune-compromised patient particularly whose with hemopoietic stem cells transplantation HSCT with incidence ratio of 30-70% and solid organ transplantation with a similar ratio of 16-56%. Risk factors:
Four major categories:
HSCT, D+/R- transplant, HIV patients and patients received lymphocytes depleting agents such as ATG and Alemtuzumab, or post Cyclophosphamide therapy.
CMV is linked to several morbidity syndromes including CMV syndome , pneumonitis, gastroentritis, retinitis ext.
Its an important etiology for allograft rejection.
cell mediated immunity is the front line immune system to control CMV virus , with CMV specific T lymphocytes are the major player mediating protection against CMV.
It was suggested that CMV specific immunity monitoring shell be part of the general assessment of risk to attract CMV infection.
Treatment:
Anti-virals is the main therapeutic against CMV infection. Nevertheless, its not safe with side effect of nephrotoxicity.
CMV specific lymphocytes confer a substituted therapeutic option to control CMV infection. CMV- Specific T cells adoptive transfer :
Transfusing CMV specific T lymphocytes shell be enhancing and rebuilding the immune system response towards CMV . It was investigated in patients with SOT,
main drawbacks of this method is T-cell response faltered owing to concurrent use of immune suppressants and because of the potential activation of alloreative cells by transferring donor derived cytolitic T lymphocytes.
CMV, EBV & BKV are a dangerous complication of SOT & bone marrow transplantation recipients.
Risk factors of CMV infection are:
CMV hero-positive HSCT
D+/R-
using of T cell depletion agent.
CMV infection can affect transplant recipient through direct effect (viral syndrome with clinical manifestation) or indirect effect as increase risk of rejection & opportunistic infection.
Cell mediated immunity is important for CMV viral infection control.
Antiviral drugs are useful in CMV infection control, but its use limited by: adverse events, resistance & high cost.
Use of adoptive transfer of CMV-specific T cell in SOT:
In HSCT the role of CMV-specific T-cell transfer used as prophylaxis & treatment for refractory CMV infection.
Adoptive therapy in SOT it not well investigated because:
attenuation of T cell response by immunosuppressive drugs.
SOT recipient may not tolerate donor delivered T lymphocytes (CLT).
Several studies prove that adoptive therapy can control CMV infection.
Also it found that adoptive therapy have mild ice effects as malaise & fatigue with out change in graft function.
Types of cellular therapy:
T-cell expiation:
CMV-specific CD8+ generation by stimulation donor PBMC with infected fibroblast, but it use stopped because it can cause infection.
CMV-lytes or PP65-NLV peptide, but it use limited to single viral epitope.
Direct selection using specific peptide MHC(PMHC):
CMV-specific T cell selected by INT-gama-cytokine capture system.
It is not HLA stricter.
It stimulate & capture polyclonal population of DC4+ &/or CD8+ T-cell depending on antigen used for stimulation.
It can be applied to any type of patient with clinical emergency due to CMV related disease.
T-cell generation using activation marker & engineered T cell (CAR,TCR):
It used successfully in cancer treatment.
It based on gene modification of patient lymphocytes with CAR or TCR.
CAR-Tcell used for CMV infection treatment as immunotherapy.
CAR-T cell exclusively identified on cell surface, while TCR can recognize intracellular antigen fragment presented by MHC molecule (limited its usefulness).
Main goal of TCR-T cell is to modify TCR binding to pathogen antigens.
Limitation of cellular therapy & alternatives in SOT:
Deficiency in T cell differentiation & life long use of immunosuppression can affect long term survival of of transferred cells which can interfere with function of adoptive therapy in SOT. Alternatives are:(a) genetical modification of generated CTL. (b) reduce immunosuppression during period of post infusion.
Deficiency of T cell differentiation due to immunosuppression, so promote CD8 & CD4 generation that can display multiple polyclonal effector function.
Transfer alloreactive T cell causing graft rejection, this can be prevented by extensive culture of T cell or establishing T cell clone to eradicate allo-reactive T cells. Also third party cells bank which can select T cell according HLA alley phenotype
Future direction & prospective:
The role of CMV-specific T cell immune reconstruction in SOT recipients is to lower risk of CMV infection % graft rejection.
To reduce limitation & difficulty of T cell expansion in SOT recipients by using third party CMV specific T cell banks & by using T cell adoptive immunotherapy.
Zang Y., Gu X., Xing J. and Chen Z. Clinical application of adoptive T cell therapy in solid tumor. Med Sci-Fi Monit,2014; 20: 953-959.
Burns D. and Crawford D. Epstein-Barr virus-specific cytotoxic T-lymphocytes for adoptive immunotherapy of post transplant lymphoproliferative disease. Blood Reviews, 2004;18(3): 193-209.
Introduction
§ Cell mediated immune response is the most important arm of the immune system against CMV infection
§ CMV-specific T-cells have a role of protection from infection with improvement in clinical care after transplantation
§ A few studies have suggested the importance of monitoring patient’s CMV-specific immunity
§ It is an option of standard treatment because of adverse effects, resistance, and high cost
§ Aim of the study: address the impact of using CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients, and a discussion of the possible use of CMV adoptive cellular therapy in this SOT population
Use of adoptive transfer CMV-specific T-cells in SOT
· Widely investigated in HSCT (less in SOT)
· Several studies were conducted in CMV-specific T-cell transfer in SOT (methods were direct selection by IFN-γ capture, Ex vivo expansion from a third party donor, and Autologous Ex vivo expansion)
· The results were promising with response (no adverse effect of infusion and viral load decreased)
· Several clinical studies are ongoing
· The use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment
Cellular therapies
Strategies for the generation of CMV-specific T-cells include:
1. Ex vivo T-cell expansion
2. Direct selection
3. Genetically engineered cells T-cell expansion
Requires the in vitro stimulation and expansion of T-cells using APCs presenting viral peptides or proteins
Advantages inclue:
1. Not restricted by HLA type
2. Small blood volume required
3. Naïve donor can be used
4. Generation of polyclonal T-cells
Disadvantages:
1. Extensive culture period
2. Seropositive donors required Direct selection
Direct selection employs virus-derived peptide specific multimers in the setting of a HLA class-I molecule, viral antigen T-cell stimulation followed by cytokine expressing T-cell selection using antibody coated immunomagnetic beads or activation marker selection based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation
Using specific peptide-MHC (pMHC) Advantages: No needed extensive ex vivo manipulation and undergo rapid expansion in vivo Disadvantages:
1. Restricted by HLA type and streptamer
2. Seropositive donors required
3. High frequency of specific T-cells needed
4. Select for a limited repertoire of CD8+ cells
Using cytokine capture system (CCS) Advantages:
1. No needed extensive ex vivo manipulation and undergo rapid expansion in vivo
2. Not restricted by HLA type
3. Isolation of polyclonal CD4+ and CD8+ cells Disadvantages:
1. Requires seropositive donors
2. Large blood volumes needed
Using activation marker
Advantages:
1. Rapid detection and enrichment of T-cells
2. Broader repertoire of antigen-specific T-cells
3. Compatible with other assay formats; not restricted by HLA
4. Not needed previous information of immunodominant epitopes
5. No specialized APC such as dendritic cells are needed Disadvantages:
1. Time-consuming and difficulty to isolate and expand functional cells
2. Identification of novel T-cell epitopes often requires screening of a high number of epitopes
T-cell generation using activation marker and engineered T-cell (CAR, TCR)
Requires gene transfer of high affinity CMV-specific T-cell receptors (TCR) or chimeric-antigen receptors (CAR) to change specificity of T-cells to CMV antigens CAR-T: advantages are:
1. Recognize antigens in an HLA-independent manner
2. Target conserved and essential epitopes
3. Infused to a broad range of patients irrespective of HLA Disadvantages:
1. Only surface antigens can be targeted
2. Restricted by epitope
3. Expensive
4. Several toxicities TCR-T: advantages are:
1. Wider range of targets
2. High affinity for specific antigens through genetic engineering
3. Strong activation when a small amount of antigen is present
4. Use of natural T-cell signaling mechanisms Disadvantages:
1. Expensive
2. Time- and labor-consuming
3. MHC restricted and depends on presentation by MHC molecules to recognize targets and activate T cell function
4. Risk of hybridization (mismatch) between exogenous and endogenous chains
Cell therapy limitations and alternatives
1. In vitro generated CMV -specific CTL are highly sensitive to immunosuppressive drugs (such as cyclosporin A and FK506) impairing the production of effector cytokines (genetically modify the in vitro generated CTL to confer resistance to these drugs or decreasing patient´s immunosuppression during a period post-infusion)
2. Deficiencies of T-cell differentiation in SOT recipients receiving immunosuppression (use the viral antigens UL123 (IE1) and UL83 (pp65), known to promote a strong T-cellular response)
3. Infusion of donor T-cells may transfer alloreactive T cells in numbers sufficient to trigger episodes of rejection (extensive culturing T cells or even establishing T-cell clones to eradicate alloreactive T cells)
Conclusions
CMV-specific T-cell has a protective role against CMV infection and disease. So, T-ell adoptive therapy may restore CMV-specific immunity for prevention and treatment in those failed to response to conventional therapy (antiviral resistance and no alternative)
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation
1. Prophylaxis and treatment of CMV Infection. It offers a new approach in treatment of drug-resistant or refractory viral infections, with early clinical trials showing promise with respect to efficacy and safety
2. BK virus nephropathy. It reduced BK viral load significantly. Early intervention may prove efficacious in BK virus nephropathy
3. EBV-associated lymphoproliferative disease. EBVSTs can be readily produced from seropositive donors using good-manufacturing practice (GMP)- compliant protocols and cryopreserved for future use
4. Prevention of acute rejection
INTRODUCTION
Cytomegalovirus (CMV), BK virus, and Epstein-Barr virus are important causes of illness and death in immunocompromised people. In immunocompetent people, latent CMV infection is managed by the immune system), but in transplant patients, both hematopoietic stem cell (HSCT) and solid organ (SOT) recipients, CMV infection is a major infectious consequence. Allogeneic HSCT patients with CMV seropositivity have the highest risk of recurrent infections. This is followed by CMV seronegative SOT recipients who get grafts from seropositive donors (R-/D+), HIV patients, and T-cell depletion therapy recipients (alemtuzumab, anti-thymocyte globulin, or post-transplant cyclophosphamide).
CMV-specific T-cell transfer in solid organ transplantation.
The CMV-specific T-cell adoptive transfer is being tested as a way to treat CMV infections and illnesses in people with ulcerative enteritis, primary immunodeficiency, or pediatric retinitis.
The CMV-specific T-cell transfer has been studied and used in patients with hematopoietic stem cell transplants (HSCT) to restore protective antiviral immunity and treat CMV infections that don’t respond to other treatments.
A kidney transplant patient (D+/R-) with refractory CMV infection got partly HLA-compatible CMV-specific T-cells at 1.6 × 107 T-cells/m2 from a third donor. Nineteen days after the infusion, the CMV DNA viral load dropped fiftyfold, and plasma exchange was stopped due to remission of thrombotic microangiopathy hematological characteristics (platelets 269 × 109/L, LDH 369 IU/L, no red cell fragments on blood film). Four weeks following the infusion, patients were released. CMV-specific CTLs from third-party donors worked, which shows that SOT users may benefit from donor cell banks.
T-Cell Expansion
Antigen-presenting cells (APC) must find the most immunogenic epitopes so that peptide-specific T-cells can become active and multiply. This is how CMV-specific T cells can be made and increased. During viral replication, several antigens activate CMV-specific CD8+ and CD4+ T-cells, which mediate the immune response.
Specific Peptide–MHC Selection (pMHC)
pMHC multimers can be used to separate T-cells by binding them to a complicated mix of peptide-loaded recombinant HLA molecules. This approach requires epitope immunodominance information due to HLA-type restrictions. HLA-peptide tetramers from pp65 and IE-1 proteins were utilized to identify CD8+ T-cells for magnetic bead isolation.
Selected Cytokine Capture System (CCS)
The IFN-g cytokine capture system (CCS) is a fast assay that selects and enriches CD8+ and CD4+ INF-g-secreting T-cells that have been primed with viral antigens to select CMV-specific T cells.
Engineered and Activation Marker-Generated T-Cells (CAR, TCR)
Another promising way to treat cancer is to change the genes of a patient’s lymphocytes to make them have tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors. (CAR). Autologous CAR T-cells may target conserved and crucial epitopes of the targeted antigen and overcome pathogen escape mechanisms.
Cell therapy limitation:
CD8+ and CD4+ T-cells with polyfunctional effector activities may better control CMV infection.
Donor T-cells may cause rejection.
T-cell clones may eliminate alloreactive T cells.
Third-party cell banks and donor registries cover numerous viral epitopes.
-possible nephrotoxicity.
the role of adoptive immunotherapy in managing different conditions related to transplantation
EBV-associated B-cell lymphoproliferative disease (BLPD)
Primary immunodeficiency disorders (PID) after HSCT · CMV and BK virus infection associated with transplantation
CMV-specific T-cell immunity are deficient in transplanted patients thereby increasing CMV replication episodes.
Adoptive transfer of CMV-specific T-cells was introduced to Hematopoietic Stem Cell Transplant patients in order to control CMV viremia. Introduction
CMV seropositive allogeneic HSCT patients, CMV seronegative SOT recipients (R-/D+), HIV patients, and recipients on T-cell depletion therapies are at high risk of CMV infections.
The CMV not only causes viral related syndrome ,but also can indirectly provoke graft rejection ,opportunistic infection and decrease recipient survival.
CMI is the main immune response for CMV infection ,therefore CMV specific T cells was adopted for CMV infection therapy.
Immunological along with virological status of the patient have to assessed to guide individualised therapy.
Available antiviral drugs have limitations as evolving of resistance and their side effects.
Therefore introducing CMV specific T cell therapy was adopted for CMV infection treatment in SOT recipients . Adoptive transfer of CMV specific T-cells in SOT
It was introduced for CMV infection treatment and ulcerative enteritis treatment in primary immunodeficiency or in pediatric CMV retinitis and as prophylaxis or therapy for CMV infection in HSCT.
The possible role of T-cell adoptive transfer as a therapy in SOT recipients was studied.
A study conducted on D+/R-transplant with refractory CMV infection and thrombotic microangiopathy declared the effective role of CMV-specific CTLs from third donors in treating the CMV infection and thrombotic microangiopathy signifying that creating donor cell-banks can be a therapeutic alternative in SOT recipients.
Another study was done on lung transplant recipient (D+/R-)with ganciclovir resistant CMV infection treated with autologous invitro expanded T cells which had favourable outcomes.
Pierucci et al. introduced autologous T-cell transfer to a seronegative lung transplant recipient with a ganciclovir and foscarnet resistant CMV infection, along with cidofovir-related nephrotoxicity ,and the CMV viral load decreased.
Another study included 21 SOT recipients of variable organs as kidney ,heart and lung transplants suffering ganciclovir resistant CMV infection treated with CMV specific T cell and the CMV symptoms resolved and the antiviral drugs were reduced or stopped .
Multiple trials are undertaken for evaluating T cell therapy in HSCT and SOT . Cellular therapies
Method s for ex vivo T cell culture involve T-Cell Expansion
Antigen presenting cells (APC) use the most antigenic epitopes to activate and enhance proliferation of peptide-specific T-cells (CMV-specific CD8+ and CD4+ T-cells), different methods are used for in vivo expansion and generation of CMV-specific T-cells.
“Polyspecific” products aiming multiple antigens were obtained byincubating allogeneic T-cells in vitro with clusters of 15-merpeptides to produce CMV specific oligoclonal T-cells. Direct Selection Using Specific Peptide–MHC (pMHC)
It enable isolation of T-cells based on the TCR ability to bind a complex mixture of peptide-loaded recombinant HLA molecules.
It requires immunodominace of epitopes knowledge and the methodology of CD4 and CD8 isolation is limited and binding can be irreversible thereby altering T cells and causing epitope specific tolerance but it was manged by Streptamer technology that can reverse the binding.
On the other hand it can save time and decrease alloreactivity.
Partially HLA-matched CMV-specific T-cells from a third party donor was used in CMV infection treatment in SOT. Direct Selection Using Cytokine CaptureSystem (CCS)
CMV-specific T-cells can be obtained by using IFN-g cytokine capture system enabling selection and enhancement of CD8+ and CD4+ INF-g secreting T-cells stimulated by viral antigens without HLA restrictions and captures a polyclonal population of CD4+ and/or CD8+ T-cells.
Another method is to gather activated viral specific T-cells after antigen stimulation by detection of specific surface molecules selectively expressed after T-cell activation. T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
Modifying the gene of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR) , it can be designed to aim certain epitopes of specific genes.
It’s draw back is that TCR T-cell therapy is restricted to MHC presentation.
Genetic engineering modifying TCR can enhance the specificity and affinity of the recognition of the antigens by T-cells as the affinity was low . Cell Therapy Limitations and Alternatives in SOT Patients
T-cell differentiation deficiencies and lifelong immunosuppression affect the long-term survival of the transfused cells, and it’s antiviral functionality and cytokine produced.
In vitro genetic modification to theses CT cells and decreasing immunosuppressives post transfusion can solve this problem
Production of CD8+ and CD4+ T-cells harbouring multiple polyfunctional effector functions can be more efficient in controlling CMV infection.
Donor derive T-cells infusion to the recipient can trigger rejection episodes.
T-cell clones cultures to eradicate alloreactive T cells can be done.
Third-party cell banks from partially HLA-matched third party donors and third party donor registries are new treatment modalities that can cover multiple viral epitopes. Future perspectives
CMV-specific T-cell therapy after SOT carries many advantages as decreasing the risk of CMV infection and graft rejection.
In fact studies on it’s use in SOT are limited meanwhile results were encouraging but difficulties of Tcell expansion in SOT receiving immunosuppressive regimens, and the risk of graft rejection after T-cell administration is a limitation.
Third-party CMV-specific T-cell banks can overcome that. Conclusion
The awareness of the role of CMV specific T cell therapy in prophylaxis and treatment of CMV resistant infection in SOT is increasing and developing also more studies are done for this promising treatment modality.
– Role of Adoptive immunotherapy in managing different conditions related to transplantation.
· Prevention and treat human cytomegalovirus (HCMV) infection in bone marrow transplant recipients
· EBV-associated B-cell lymphoproliferative disease (BLPD)
· Primary immunodeficiency disorders (PID) after HSCT
· Adoptive immunotherapy with virus-specific T lymphocytes (VSTs) produces antiviral immunity after HSCT that is effective for treatment or prevention of viral infections with CMV, EBV, and adenovirus (AdV) with minimal risk of GVHD .
Reference
-Haque T etal .THE ROLE OF ADOPTIVE IMMUNOTHERAPY IN THE PREVENTION AND TREATMENT OF LYMPHOPROLIFERATIVE DISEASE FOLLOWING TRANSPLANTATION .British Journal of Haematology 1999 (106): 309-316
-McLaughlin LP, Bollard CM, Keller M. Adoptive T Cell Immunotherapy for Patients with Primary Immunodeficiency Disorders. Curr Allergy Asthma Rep. 2017;17(1):3. doi:10.1007/s11882-017-0669-2
Viral infections like CMV, EBV, and BK remain one of the significant causes of morbidity and mortality in immunosuppressed patients
CMV seropositive HSCT, and CMV D+/R- portend a high risk of recurrence of infection
CMV infection has both direct and indirect effects on the patient in an immunosuppressive state
Cell medicated immune system is considered the backbone of the prevention of CMV disease.
Many of the antiviral drugs against CMV disease are not only nephrotoxic but some level of resistance can be developed against one or two of them
The above challenge has led to the development of CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients
Use of adoptive transfer of CMV-specific T cell in the context of SOT
The CMV-specific T-cell transfer has been well researched and applied to HSCT patients, prophylactically, to reconstitute protective antiviral immunity, and as a treatment in patients with refractory CMV infection
The use of the above therapy in SOT has been less investigated, though few authors have variable clinical outcomes
The most prominent study was done on 21 SOT recipients (13 kidneys, 8 lungs, and 1 heart) and 13 received T-cell adoptive transfer
Eleven out of thirteen of them showed an improvement in their symptoms and resolution of CMV disease
A lot of studies are ongoing because of the above promising success
Methods of generating CMV specific T cell
The first method used was in vivo, where CMV-specific CD8+ T-cell clones were generated by stimulating donor peripheral blood mononuclear cells (PBMC) with CMV-infected fibroblasts. It was stopped because of risk of producing an infection.
The following are the ex vivo expansion method which has reduce alloreactive effect:
Direct selection using a specific peptide- MHC (pMHC)
Direct selection using a cytokine capture system (CCS)
T-cell generation using activation marker and engineered T cells (CAR, TCR)
Cell therapy limitation and alternative in SOT patient
predisposition to wide variety of viral infections complications
selection of drug resistant mutant CMV strain
it can cause nephrotoxicity
deficiencies of T-cell differentiation in SOT recipient receiving immunosuppression
The creation of third-party cell banks as well as third party donor registries has emerged as a new possibility of treatment that employs T-cells derived from partially HLA-matched third party donors. The allows rapid off shef use of the medication
Future direction and perspective
Most of the studies on adoptive CMV specific T cell transfer was done on HSCT with only few on SOT recipients.
The future direction will be to generate a ready made to use third part CMV specific T cell bank to ensure availability of well matched T cell products
Conclusion
The available body of knowledge has shown the protective role of CMV specific T cell immune response to CMV infection and disease
The role of Adoptive immunotherapy in managing different conditions related to transplantation
Treatment of resistant EBV PTLD
The treatment for CMV infection and disease in ulcerative enteritis in primary immunodeficiency
Is It Feasible to Use CMV-Specific T-Cell Adoptive Transfer as Treatment Against Infection in SOT Recipients?
1-Please summarise this article: Introduction; -Viral infection, including cytomegalovirus (CMV), BK virus and Epstein-Barr virus, remains a major cause of morbidity and mortality in immunocompromised individuals.
-The incidence of CMV reactivation/reinfection in SOT is 16–56% , while in HSCT has been reported to be 30–70%.
-Cell mediated immune response is considered the most important arm of the immune system against CMV infection with increasing evidences demonstrating a role of CMV-specific T-cells in protecting from infection, which can contribute to improve clinical care after transplantation. Methods to generate CMV specific T-cells; –T-cell expansion: -Many antigens expressed during viral replication play role in the activation of both CMV specific CD8+ and CD4+ T-cells, and are known enhance immune response against the virus. e.g. IE-1 & pp65. -Direct selection using specific peptide – MHC (pMHC): -T cells are isolated based on their ability to bind a complex mixture of peptide-loaded recombination HLA molecules.This may improve the quality of the final product but it is only limited to isolation of CD8+ or CD+ T cell population. -Direct selection using cytokine capture (CCS):
-This is based on INF-gamma cytokine system. -It has no HLA limitation compared to pMHC. -T cell generation using activation marker and engineered T-cells (CAR, TCR): -The generation of CAR allows antigen recognition without the need of MHC and can be designed to specifically target conserved and essential epitopes of the antigen in question. Use of Adoptive Transfer of CMV-Specific T-Cells in the Context of Solid Organ Transplantation;
-CMV is a major cause of severe complications in SOT recipients such as graft loss especially in patients that develop CMV infection with antiviral refractory CMV strains.
-The period early after the transplant is considered critical due to the high risk of infections associated with a high incidence of CMV.
-The role of CMV-specific T-cell immune reconstitution after SOT have demonstrated several benefits, including lower risk of CMV infection and graft rejection.
-Thus, the development and improvement of new CMV-specific T-cell transfer based therapies could be a useful to adjust the therapeutic interventions.
-However, despite the increasing interest on adoptive CMV specific T-cell transfer, most of the information available comes from studies in HSCT recipients.
-Only few reports including a small number of SOT recipients have used T-cell adoptive immunotherapy as a treatment of CMV infection or disease.
-Together these results suggest that, although there is still space for improvement, the use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment. Cell Therapy Limitations and Alternatives in SOT Patients;
-The intensity and long-term immunosuppression requirement to prevent allograft rejection pre-disposes SOT recipients to a wide range of viral complications.
-In addition,antiviral treatment can generate side effects such as nephrotoxicity,and the selection of drug-resistant mutant CMV strains, limiting treatment capability in SOT recipients.
-Based on these limitations, cell therapy may be an appropriate and effective alternative antiviral treatment.
-However,deficiencies in T-cell differentiation and lifelong immunosuppression can affect to long-term survival of the transfused cells,interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipients.
-Another limitation is associated with deficiencies of T-cell differentiation in SOT recipients receiving immunosuppression.
-One possible approach to overcome these limitations is generating ready to use third-party CMV-specific T-cell banks to ensure the availability of well characterized the T-cell products. Conclusion; -The use of T-cell adoptive therapy may help to restore the CMV-specific immunity for preventing CMV infection in SOT individuals who do not respond to conventional therapies, such as patients infected with antiviral resistant strains. -Further work is clearly needed in order to fully understand and assess the clinical utility of these techniques in Sot recipients. 2–Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation. –Adoptive immunotherapy uses EBV-specific cytotoxic T lymphocytes (EBV-CTLs) or donor lymphocyte infusion (DLI) in an attempt to kill dividing B cells in EBV-associated PTLD. -Most data using this approach come from retrospective series and small observational studies in hematopoietic cell transplantation (HCT) recipients. In this population, prevention of and remission of EBV-induced PTLD have been achieved in this manner in as many as 90 percent of patients. -The major complication of adoptive immunotherapy is acute and chronic graft-versus-host disease (GVHD). -DLI may produce GVHD, which does not appear to be a problem with EBV-CTLs.
I like your reflections and summary. I wish you could type references to support your arguments. I appreciate your concern about the risk of causing graft Vs host disease.
CMV infection after transplantation is common; around one third of patients receiving organ may develop CMV infection
CMV infection can affect the outcome of SOT through various mechanisms :
CMV may infect the graft and cause graft dysfunction
Reduction of immunosuppression may predispose to rejection
The use of antiviral is associated with side effects
The principle of adoptive immunotherapy in treatment of CMV infection after transplantation is using CMV specific cytotoxic T lymphocytes (ex vivo T-cell culture) or donor lymphocyte infusion to kill CMV infected cells.
The transfer of CMV-specific T-cell is widely used in Hematopoietic Stem Cell Transplant (HSCT) patients; on the other hand it is less studied in the settings of organ transplantation which may be explained by the rule of immunosuppression which may attenuate T cell response, moreover, infusion of donor lymphocytes may cause immune response and graft versus host disease
Side effects of adoptive immunotherapy
The main side effect of this therapy is the development of graft versus host disease which is less common if using CMV specific cytotoxic T lymphocytes , and very common when using donor derived lymphocytes
Allergic reactions
General flue like symptoms
Cellular therapy available for generation of CMV specific T-cells:
1. T-cell expansion:
2. Direct selection using specific peptide – MHC (pMHC)
3. Direct selection using cytokine capture (CCS)
4. T-Cell Generation Using Activation Markerand Engineered T-Cells (CAR, TCR)
Cell Therapy Limitations and alternatives in SOT Patients
The main limitation for the use of cellular therapy is the use of long term immunosuppression that can affect the long term survival of transfused T cells , this can be managed by reduction of immunosuppression once the cells are transfused and to genetically modify the in vitro generated cytotoxic T cell to allow for resistance to the immunosuppressive drugs.
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
1. Treatment of resistant and refractory cases of EBV+ PTLD cases
2. May be used for the treatment of acute rejection through infusing Treg cells
3. Treatment of resistant cases of CMV, BK nephropathy
IV.Is It Feasible to Use CMV-Specific T-Cell Adoptive Transfer as Treatment Against Infection in SOT Recipients?
Many studies have shown the role of CMV specific T-cell immune response on controlling CMV replication and dissemination.
Transplanted patients lacking CMV-specific T- cells have an increased occurrence of replication episodes and complications.
We propose a novel review in which we provide an overview of the impact of using CMV/CMV adoptive transfer on the control of infection in SOT recipients.
Viral infection remains a major cause of morbidity and mortality in immunocompromised individuals.
In stem cell and solid organ transplant recipients, CMV infection is one of the main infectious complications.
CMV seropositive allogeneic HSCT patients presents the highest risk of recurrent infections.
The incidence of CMV reactivation/reinfection in SOT is 16–56% (8–12), while in HSCT has been reported to be 30–70%.
Cell mediated immune response is considered the most.important arm of the immune system against CMV infection, with increasing evidences demonstrating a role of CMV-specific.
T-cells in protecting from infection, which can contribute to improve clinical care after transplantation.
The use of standard tools for assessing the risk of CMV infection after transplantation could help make more informed decisions about how best to treat patients with CMV-related infections.
The use of antiviral drugs to treat CMV infection has been on the increase for many years, but there are still some issues with the current treatments such as side effects (nephrotoxicity) and selection of resistance mutations in addition to the high cost.
The use of adoptive cellular therapy may be useful to modulate the CMV specific T-cell response and to control CMV viremia in SOT recipients. Here we provide a synthesis of data regarding the impact of using CMV-specific T- cell transfer on the control of CMV infection in patients with sickle cell anemia.
Use OF Adoptive Transfer OF CMV- Specific T-cells IN The Contex OF Solid Organ Transplantion
The use of CMV-specific T-cell adoptive transfer is currently. being evaluated for clinical application, with promising results as treatment for CMV infection and disease in ulcerative enteritis or in pediatric retinitis caused by CMV.
Stem cell transplantation has been used to reconstitute protective antiviral immunity in stem cell transplant (SOT) patients and to treat refractory CMV infection.
SOT patients may not tolerate donor-treated cytolytic T lymphocytes (CTLs) due to the activation of alloreactive T-cells causing indirect alloimmune injury.
In 2009, Brestrich et al. performed a study in a lung transplanted recipient with a severe and persistent CMV pneumonia resistant to ganciclovir and foscarnet.
The patient was treated with two infusions of 1 × 10 7 /m2 CMV‐specific T-cells. After the first infusion, the patient developed an overall improvement but later died from the disease.
A patient with refractory CMV infection was treated with partially HLA-compatible CMV-specific T-cells at a dose of 1.6 × 107 T- cells/m2.
Patients was discharged from hospital four weeks after the infusion.
The authors of a study suggests that creating donor cell-banks could be useful as a therapeutic alternative in SOT recipients. In a second study, they successfully expanded autologous CMV-specific T-cells from a seronegative recipient that received a lung allograft and that developed a CMV disease.
Autologous T-cell therapy can contribute to immune control of CMV infection, as shown by Pierucci et al. in a lung transplant recipient with a ganciclovir and CMV resistant lung infection.
The patient’s usual immunosuppression regime was resumed, hepatic and bone marrow function remained normal and there was no evidence of acute rejection.
The patient did not have any documented rejection or acute change in lung function after the infusions.
The most ambitious study carried out to date was performed in a cohort of 21 SOT recipients (13 kidney, 8 lung and 1 heart) who developed recurrent ganciclovir resistant CMV infections.
Thirteen of these patients were subjected to T-cell adoptive transfer and showed objective improvement in their CMV symptoms.
The use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment, according to the authors.
The first results from a clinical trial will be available at the end of 2021.
During the last years a better understanding of the CMV-specific T-cell immunology has led to the improvement of the methods for ex vivo T- cell culture.
In this section, we describe the features of the various methods available to generate CMV specific T-cells.
A large number of antigens expressed at different stages during viral replication participate in the activation of both CMV-specific CD8+ and CD4+ T-cells, known to mediate the immune response against the virus.
The development of CMV-specific T-cell clones has been a major area of research in the field of oncology .
Different approaches have been used to generate CD8+ T-cells from stem cells and fibroblasts expressing CMV.
Adoptive transfer of these T-cell products was able to eliminate viremia, and infused infusions persisted for up to two years.
The improvement of the methodology for ex vivo expansion has reduced the presence of alloreactive or naive T-cells in the final product .
T-cell ex vivo stimulation and expansion requires a small blood volume to establish the T- cell culture, making possible the generation of CMV-specific T- cells.
Direct Selection Using Specific Peptide–MHC (pMHC)
Using pMHC multimers allows to isolate T-cells based on the T- cells receptor (TCR) ability to bind a complex mixture of HLA molecules.
Since this method is restricted by HLA type, previous knowledge about the immunodominance of the epitopes is necessary.
Advantages and disadvantages of this technique are related with the limitation of the method to isolate only CD8+ or CD4 T-cell populations, and the irreversibility of the binding that can ause changes in the T- cell phenotype.
This intrinsic characteristic of pMHC multimer binding substantially limits the clinical application of this technology.
Streptamer technology has led to the development of T-cell therapy, in which CD8+ T-cells are isolated from CMV seropositive donors and their CD4+ counterparts are not affected.
The results obtained with this technology are promising however, further studies are necessary to demonstrate efficacy in SOT recipients.
This approach has been shown to be safe and effective in SOT patients, but more research is needed .
Direct Selection Using Cytokine Capture Using Cytokine Capture System (CCS)
CMV-specific T-cells can also be selected using IFN-g cytokine capture system.
This rapid assay allows to select and enrich CD8+ and CD4+ secreting T- cells that have been previously stimulated using viral antigens.
This is the first time that a human cell-directed therapy (CTL) has been developed for the treatment of patients with CMV-related diseases including SOT recipients.
The approach has the potential to be applicable to any type of patient with a clinical-emergency due to CMV related diseases, such as those who have had their ovaries removed.
Another selection strategy is to isolate and enrich activated viral- specific T-cells after antigen stimulation based on the detection of surface molecules that are selectively expressed or strongly up-regulated after T-cell activation.
This approach allows simultaneous targeting of antiviral T-helper and effector cells.
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
T-Cell Generation Using Activation Marker (AM) and Engineered T-Cells (CAR, TCR) is one of the most recent developments in the field of cell-based cancer treatment.
The generation of CAR T-cells enables antigen-recognition in a MHC independent manner and can be designed to specifically target conserved and essential epitopes of the selected antigen.
In this article, we examine how to generate gB-targeted CARs with CD4+ and CD8+ T-cells derived from CMV-seronegative donors.
The TCR strategy uses heterodimers integrated by alpha and beta peptide chains to recognize specific polypeptide fragments presented by MHC complexes.
While CAR-T-cell therapy identifies exclusively antigens located in the cell surface, TCR can also recognize intracellular antigenic µmagnifications.
Patients Cell therapy may be an appropriate and effective alternative antiviral treatment for SOT patients.
However, deficiencies in T-cell differentiation and lifelong immunosuppression can affect to long-term survival of the transfused tissues.
Here, we analyze the alternatives available to overcome these limitations.
In vitro studies have shown that in vitro generated CMV-specific T-cells (CTLs) are highly sensitive to immunosuppressive drugs such as cyclosporin A and FK506.
Methylation of the CTL could enable them to confer resistance to these drugs, leading to an expansion of their functionality.
The use of third-party CMV-specific T- cells could be used in patients that admit a reduction of the immunosuppression regimen without compromising the allograft stability.
However, efforts should be made to promote the generation of CD8+ and CD4+ T-cells displaying polyfunctional effector functions.
Infusion of donor derive T-cells from donors may also transfer alloreactive T cells in numbers sufficient that could trigger episodes of rejection.
This is because the donor and the host differ in one or more HLA alleles, due to sensitization to specific non-self HLA ones present on the donor T-cell.
The creation of third-party cell banks as well as third party donor registries has emerged as a new possibility of treatment that employs T-cells derived from partially HLA-matched third- party donors.
The use of this method allows to achieve a rapid “off the shelf” product that could be used in a broader range of patients.
Despite the fact that further research is needed, the preliminary findings are very encouraging.
CMV is a major cause of severe complications in SOT recipients such as graft loss.
The period early after the transplant is considered critical due to the high risk of infections.
However, despite the increasing interest on adoptive CMV specific T-cell transfer, most of the information available comes from studies in HSCT recipients.
A number of clinical trials have shown promising results in stem cell transplantation (SOT), but development has been limited due to difficulties of T- cell expansion and the risk of graft rejection after T-cell administration.
One possible approach to overcome these limitations is generating ready to use third-party CMV-specific T- cells.
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
Adoptive immunotherapy is a method of activating lymphocytes and/or other types of cells for the treatment of cancer and other diseases.
Cells are removed from the patient, processed for some period of time, and then infused back into the patient.
Reduced-intensity conditioning cell transplantation relies on a donor-versus-malignancy effect of donor lymphocytes.
Adoptive immunotherapy uses “activated lymphocytes” as a treatment modality.
The nonspecific, polyclonal proliferation of lymphocytes by cytokines (immune system growth factors), also called autolymphocyte therapy, increases the number of activated lymphocytes.
Adoptive Immunotherapy:-
If conventional treatment fails.
It uses EBV-specific cytotoxic T lymphocytes (EBV-CTLs) or donor lymphocyte infusion (DLI) in an attempt to abort the EBV-driven proliferation of B cells in EBV-associated PTLD.
Most of the data come from retrospective series and small observational studies in hematopoietic cell transplantation (HCT) recipients.
Prevention and remission of EBV-induced PTLD have been achieved in 52 to 75% of patients.
Adoptive Immunotherapy:-
Improving T-cell Therapy for Epstein-Barr Virus Lymphoproliferative Disorders. Bollard. J Clin Oncol, 2013 Jan 1;31(1) 5-7.
Epstein-Barr virus-related post-transplant lymphoproliferative disease (EBV- PTLD) in the setting of allogeneic stem cell transplantation: a comprehensive review from pathogenesis to forthcoming treatment modalities. Al Hamed et al. Bone Marrow Transplant. 2020 Jan;55(1):25-39.
The use of T-cell adoptive therapy may help to restore the CMV-specific immunity for preventing CMV infection in SOT individuals who do not respond to conventional therapies, such as patients infected with antiviral resistant strains
. Further work is clearly needed in order to fully understand and assess the clinical utility of these techniques in Sot recipients.
T cell mediated immune response is an important part of immune response against CMV infection with new evidence suggesting the role CM V-specific T cells in prevention of infection.
This may lead to better clinical management after transplantation
The use of CMV- specific T-cell adoptive transfer is currently being evaluated for clinical application, with promising results as a treatment for CMV infection and disease, in ulcerative enteritis, in primary immunodeficiency or in pediatric retinitis caused by CMV
Justifications for T cell adoptive therapy would be; the currently available long-term immune suppression may put the patients at high risk of viral complications and the current antiviral therapy is associated with significant side effects including nephrotoxicity. Therefore cell therapy may be reasonable and effective alternative antiviral treatment
Methodologies to generate CMV specific T-cells
A.T-cell expansion:
Many antigens expressed during viral replication play role in the activation of both CMV specific CD8+ and CD4+ T-cells, and are known enhance immune response against the virus. e.g. IE-1 & pp65
B.Direct selection using specific peptide – MHC (pMHC):
T cells are isolated based on their ability to bind a complex mixture of peptide-loaded recombination HLA molecules.This may improve the quality of the final product but it is only limited to isolation of CD8+ or CD+ T cell population.
C.Direct selection using cytokine capture (CCS):
This is based on INF-gamma cytokine system
It has no HLA limitation compared to pMHC
D.T cell generation using activation marker and engineered T-cells (CAR, TCR):
The generation of CAR allows antigen recognition without the need of MHC and can be designed to specifically target conserved and essential epitopes of the antigen in question
Limitation of the cellular therapy & alternatives in SOT:
Limitations;
Deficiencies in T cell differentiation
The use of long-term immune-suppression in solid organ transplantation (SOT)
Alternative solutions;
Genetic modification of the in vitro generated CTL , so that they became resistant to the effect of long-term immune-suppressive drugs
Reduce immune-suppression after infusion of cell base therapy to allow their expansion and functionality
Future directives & perspectives;
Third party CM-specific T cell banks to ensure the availability of well characterized T -cell products
Conclusion:
The use of adoptive immunetherapy may contribute to the recovery of CMV- specific immunity and protect against CMV infection. It can be use as a treatment for those with resistant CMV infection and no other therapeutic option in SOT. It is important to understand the limitations of these therapy and the need for further research to conceptualize and evaluate the clinical utility of treatment in SOT.
The use of CMV- specific T-cell adoptive transfer is currently being evaluated for clinical application, with promising results as a treatment for CMV infection and disease, in ulcerative enteritis, in primary immunodeficiency or in pediatric retinitis caused by CMV
Justifications for T cell adoptive therapy would be; the currently available long-term immune suppression may put the patients at high risk of viral complications and the current antiviral therapy is associated with significant side effects including nephrotoxicity. Therefore cell therapy may be reasonable and effective alternative antiviral treatment
With encouraging results as a treatment for CMV infection and disease in ulcerative enteritis in primary immunodeficiency or in pediatric retinitis caused by CMV, CMV-specific T-cell adoptive transfer is currently being studied for clinical application.
CMV-specific T-cell transfer has received a lot of attention in the context of transplantation and has been used to treat refractory CMV infection in patients who have received hematopoietic stem cell transplants (HSCT) as well as prophylactically to restore protective antiviral immunity.
In contrast, it has likely received less research attention in SOT recipients due to the immunosuppressive therapy’s reduction of the T-cell response.
Additionally, due to the activation of cytokine-mediated stimulation of the alloreactivity T-cells causing SOT patients to not tolerate donor-derived cytolysis T lymphocytes (CTLs), causing direct alloimmune injury .
García-Ríos E, Nuévalos M, Mancebo FJ, Pérez-Romero P. Is It Feasible to Use CMV-Specific T-Cell Adoptive Transfer as Treatment Against Infection in SOT Recipients?. Front Immunol. 2021;12:657144. Published 2021 Apr 23.doi:10.3389/fimmu.2021.657144
Results of several trials show that although there is still space for improvement, use of CMV specific T cell adoptive transferase is promising in treatment of refractory CMV infection( with limited available option of treatment).
– INTRODUCTION :Transplant patients being immunocompromised are prone to have viral infections like cytomegalovirus (CMV), BK virus and Epstein-Barr virus, which remains a major cause of morbidity and mortality. HSCT patients have more chances of CMV reinfection and reactivation with the incidence of 16-56% and 30-70% than SOT. Previously only antiviral treatment for CMV was available but do have adverse effects so recently`to overcome these limitations , cell therapy like CMV-specific T-cell immune reconstitution was being developed.
CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients.
This adoptive transfer not well studied in SOT due to weaken T cell response and might the recipient not tolerate donor delivered T lymphocytes (CLT),however , indicated for CMV viremia and refractory CMV in HSCT.
Mutiple studies have been conducted on T cell therapy in HSCT and SOT .One study substantiated that donor cell bank can be a source of CMV-specific CTLs in treating the CMV infection and thrombotic microangiopathy on D+/R-transplant patients. Similarly another study conducted with autologous invitro expanded T cells on lung transplant recipient (D+/R-) revealed good outcome for ganciclovir resistant CMV infection .
Types of cellular therapy:
T-cell expiation
Direct selection using specific peptide MHC(PMHC)
T-cell generation using activation marker & engineered T cell (CAR,TCR):
Cell therapy limitations and alternatives
Long term survival of the transfused cells affected , also increase chances of rejection, so genetic modification to these T cells and decreasing immunosuppressive post transfusion can help to solve this issue.
Future directions and perspectives
1. Third-party CMV-specific T-cell banks
2. T-cell adoptive immunotherapy
The role of Adoptive immunotherapy in different conditions related to transplantation
Prophylaxis and treatment of CMV Infection.
BK virus nephropathy.
EBV-associated lymphoproliferative disease.
During the last decades ,CMV resistence is emerging ,and one of the new stratigy is to use the CMV specific T cell receptors .
n this context, the use of adoptive transfer of CMV-specific T-cells has been widely investigated and applied to Hematopoietic Stem Cell Transplant patients and may be useful as a therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia in patients receiving a transplantation. However, only few authors have explored the use of T-cell adoptive transfer in SOT recipients. We propose a novel review in which we provide an overview of the impact of using CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients, the different approaches to stimulate, isolate and expand CMV-specific T-cells developed over the years and a discussion of the possible use of CMV adoptive cellular therapy in this SOT population. Given the timeliness and importance of this topic, we believe that such an analysis will provide important insights into CMV infection and its treatment/prevention.
The use of cellular therapy may be useful to reconstitute the CMV specific T-cell response and to control CMV viremia in SOT recipients. The use of CMV-specific T-cell adoptive transfer has promising results in treating CMV infection and disease, in ulcerative enteritis in primary immunodeficiency or in pediatric retinitis caused by CMV . Hematopoietic Stem Cell Transplant (HSCT) patients, adopt this as both prophylactically, to reconstitute protective antiviral immunity, and as a treatment in patients with refractory CMV infection.
Strategies for the generation of CMV-specific T-cells:
1- Ex vivo T-cell expansion requires the in vitro stimulation and expansion of T-cells using APCs presenting viral peptides or proteins.
2- Direct selection employs virus-derived peptide specific multimers in the setting of a HLA class-I molecule, viral antigen T-cell stimulation followed by cytokine expressing T-cell selection using antibody coated immunomagnetic beads or activation marker selection based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation.
3- Genetic manipulation requires gene transfer of high affinity CMV-specific T-cell receptors (TCR) or chimeric-antigen receptors (CAR) to change specificity of T-cells to CMV antigens.
Cell Therapy Limitations and Alternatives in SOT Patients:
The intensity and long-term immunosuppression requirement to prevent allograft rejection pre-disposes SOT recipients to a wide range of viral complications
In addition, antiviral treatment can generate side effects such as nephrotoxicity , and the selection of drug-resistant mutant CMV strains
A possible solution in order to overcome this problem, is to genetically modify the in vitro generated CTL to confer resistance to these drugs or decrease patient´s immunosuppression during a period post-infusion and use of third-party T-cells to infuse a kidney transplant patient who had ganciclovir resistant persistent CMV viremia, and decreased the levels of immunosuppressive drugs.
During the last decade, many studies have demonstrated the role of CMV specific T-cell immune response on controlling CMV replication and dissemination. In fact, it is well established that transplanted patients lacking CMV-specific T-cell immunity have an increased occurrence of CMV replication episodes and CMV-related complications. In this context, the use of adoptive transfer of CMV-specific T-cells has been widely investigated and applied to Hematopoietic Stem Cell Transplant patients and may be useful as a therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia in patients receiving a transplantation. However, only few authors have explored the use of T-cell adoptive transfer in SOT recipients. We propose a novel review in which we provide an overview of the impact of using CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients, the different approaches to stimulate, isolate and expand CMV-specific T-cells developed over the years and a discussion of the possible use of CMV adoptive cellular therapy in this SOT population. Given the timeliness and importance of this topic, we believe that such an analysis will provide important insights into CMV infection and its treatment/prevention.
New advances in cancer biology has resulted in highly specified immune therapy instead of toxic non-specific chemotherapy . Adoptive immunotherapy is a new way of treating malignancy by involving the patient own immune system to attack the cancer cell. It is a variant of transfusion therapy for malignancy, it was introduced with aim of eliminating tumour and preventing their relapse . It is still not widely used, but seem to have promising result in, even, metastatic cancer. It was found that subcutaneous growth of human tumor autografts to patients bearing advanced cancers was inhibited by the co transfer of autologous leukocytes in about half of the patients. Adoptive T cell therapy involves infusion of autologous and allogenic T cell in the patient with cancer. It uses tumour infiltrating lymphocyte (TIL) or chimeric antigen receptor (CAR) T cells. It is used in some cancers including metastatic melanoma.
USE OF ADOPTIVE TRANSFER OF CMVSPECIFIC T-CELLS IN THE CONTEXT OF SOLID ORGAN TRANSPLANTATION
It has promising results as a treatment for CMV infection and disease in ulcerative enteritis in primary immunodeficiency or in pediatric retinitis caused by CMV
It applied to (HSCT) patients, both prophylactically, and as a treatment in patients with refractory CMV infection
In contrast, in SOT recipients it has been less investigated
●In 2009, Brestrich et al. performed a study in a lung transplanted recipient with a severe and persistent CMV pneumonia resistant to ganciclovir and foscarnet.
The patient was treated with two infusions of 1 × 107/m2 CMV‐specific T-cells.
After the first infusion, the patient developed an overall improvement. However, the patient died due to graft failure with a negative biopsy for CMV antigen
●In one study, nineteen days following the infusion, a fifty fold decreased of the CMV DNA viral load was observed
The authors highlighted the effective application of CMV-specific CTLs from third donors, suggesting that creating donor cell-banks could be useful as a therapeutic alternative in SOT recipients
● In a later study, the same group successfully expanded autologous CMV-specific T-cells from a seronegative recipient that received a seropositive lung allograft and that developed a CMV disease due to ganciclovir resistant CMV infection.
The patient received four infusions of 3 × 107 autologous T-cells. After the infusion of the in vitro expanded T-cells no adverse events occurred, the CMV viral load became undetectable, the patient’s usual immunosuppression regime was resumed, hepatic and bone marrow function remained normal with no evidence of acute rejection.
These results indicated that adoptive therapy can contribute to immune control of CMV infection
CELLULAR THERAPIES AVAILABLE the conserved T-cell epitopes , has led to the improvement of the methods for ex vivo T-cell culture
rapid tests to evaluate the effector function of the CMV-specific T-cells have become available
T-Cell Expansion
A large number of antigens expressed at different stages during viral replication participate in the activation of both CMV-specific CD8+ and CD4+ T-cells
IE-1 and pp65 proteins are two of the most immunodominant CMV antigens
Different approaches have been carried out for in vivo expansion and generation of CMV-specific T-cells
CMV lysates or pp65-NLV peptide were used to stimulate CMV-specific T-cells
Using the pp65-NLV peptide only stimulated adoptive immunity against a single viral epitope and its application may be limited for HLA-A2patients/donors .
To overcome this problem, “polyspecific” products targeting multiple antigens were generated by incubating allogeneic T-cells in vitro with clusters of 15-mer peptides spanning the entire pp65 antigen to generate CMVspecific oligoclonal T-cells.
Direct Selection Using Specific Peptide–MHC (pMHC)
a previous knowledge about the immuno dominance of the epitopes is necessary.
HLA peptide tetramers from pp65 and IE-1 proteins have been previously used to select CD8+ T-cells that were further isolated using magnetic beads
This method allows to
●reduce the time and improve the quality of the final product
●minimizing alloreactivity .
the disadvantages of this technique
○ the limitation of the method to isolate only CD8+ or CD4 T-cell populations,
○ the irreversibility of the binding that can cause changes in the T-cell phenotype, leading to functional alterations of the purified T-cell population
Direct Selection Using Cytokine Capture System(CCS)
A rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral antigens
It has no HLA restriction and as an additional benefit stimulating and capturing a polyclonal population of CD4+and/orCD8+T-cells.
Kim et al. used the automated CliniMACS
Prodigy platform to generate pp65-specific CTL that exhibited functional activity, sustained antigen-specificIFN-g secretion, and cytotoxicity against pp65-pulsed target T-cells.
Although little clinical experience is available, this approach has the potential to be applicable to any type of patients with a clinical emergency due to CMV-related diseases including SOT recipients
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
It enables antigen recognition in a MHC independent manner and can be designed to specifically target conserved and essential epitopes of the selected antigen
CAR consists of a defined antigenbinding domain represented by a single-chain fragment variable (scFv) antibody, an extracellular spacer region, a transmembrane domain, and an intracellular domain that triggers T-cell activation, mainly by the T-cell receptor signaling domain.
In a recent study, CD4+ and CD8+ T-cells obtained from blood or cord blood of CMV-seronegative donors were transduced showing efficacy in preclinical models
While CAR-T-cell therapy identifies exclusively antigens located in the cell surface, TCR can also recognize intracellular antigenic fragments presented by MHC molecules. However, TCR T-cell therapy is restricted to MHC presentation, which represents a limitation of the strategy.
The main goal of TCR T-cells is to modify the TCR binding to the pathogen antigens. Naturally, the affinity of TCRs for the pathogen antigens is very low, which difficult the recognition.
To overcome this problem, modifications of the TCR using genetic engineering technology has been able to enhance the specificity and affinity of the recognition of the antigens by T-cells
Cell Therapy Limitations and Alternatives in SOT Patients
further development have been limited due to
● difficulties of Tcell expansion in SOT that are receiving immunosuppressive regimens
● the risk of graft rejection after T-cell administration.
One possible approach to overcome these limitations is generating ready to use third-party CMV-specific T-cell banks to ensure the availability of well characterized the T-cell products.
CONCLUSIONS
Recent findings regarding the development of new techniques to select, isolate and enrich functional CMV-specific T-cells and the possible generation of third party donor cell banks may help to use CMV-specific adoptive transfer as an alternative therapy for SOT recipients.
2- It may use in treatment of PTLD – BK – HCV- CMV after transplantation
Ganciclovir-resistant (GanR) cytomegalovirus (CMV) is an emerging clinical problem in organ transplant recipients, particularly recipients of kidney and pancreas and lung transplants. GanR CMV, a late posttransplantation complication, is observed predominantly among CMV-seronegative recipients of organs from seropositive donors, especially among recipients receiving intensive immunosuppression and having prolonged exposure to ganciclovir. Given the limitations of current diagnostic methods, if GanR CMV is clinically suspected, empirical treatment with intravenously administered foscarnet should be used in conjunction with reductions in immunosuppressive therapy and possibly CMV hyperimmune globulin. Better diagnostic tools and newer, less-toxic antiviral agents with different mechanisms of action are urgently needed to decrease the morbidity associated with this complication in organ transplant recipients.
Cytomegalovirus (CMV) infection remains a major complication following allogeneic hematopoietic stem cell transplantation (HSCT). T cell response plays a critical role in inducing long‐term immunity against CMV infection/reactivation that impairs during HSCT. Adoptive T cell therapy (ACT) via transferring CMV‐specific T cells from a seropositive donor to the recipient can accelerate virus‐specific immune reconstitution. ACT, as an alternative approach, can restore protective antiviral T cell immunity in patients. Different manufacturing protocols have been introduced to isolate and expand specific T cells for the ACT clinical setting. Nevertheless, HLA restriction, long‐term manufacturing process, risk of alloreactivity, and CMV seropositive donor availability have limited ACT broad applicability. Genetic engineering has developed new strategies to produce TCR‐modified T cells for diagnosis, prevention, and treatment of infectious disease. In this review, we presented current strategies required for ACT in posttransplant CMV infection. We also introduced novel gene‐modified T cell discoveries in the context of ACT for CMV infection.
CMV is one of the main causes of morbidity and mortality in immunocompromised individuals.
The incidence of CMV reactivation/reinfection in SOT is 16 to 56%.
CMV proliferation lead to viral syndrome ( gastroenteritis, pneumonitis,uveitis, hepatitis) and also cause indirect effects ( graft rejection, increased incidence of opportunistic infections and decreased recipient survival).
Cell mediated immune response is considered the most important arm of the immune system against CMV infection with the important role of CMV specific T cell in protecting against infection.
Although the use of antiviral medications is useful in treatment of CMV infection, but there is some issues about their high cost and their side effects . So there is a need for new therapeutic approaches.
The use of cellular therapy may be useful to reconstitute the CMV specific T cell response and to control CMV viremia in SOT recipients.
The use of adoptive transfer of CMV specific T cells in the context of SOT
CMV specific T cell transfer has been investigated and applied to HSCT patients as a protective antiviral immunity and as a treatment in patients with refractory CMV infection.
But in SOT recipients, it is less investigated due to the T cell response attenuation produced by the immunosuppression. Also SOT recipients may not tolerate donor derived cytolytic T lymphocytes due to stimulation of the alloreactive T cells and direct alloimmune injury.
Cellular therapies available
1. T cell expansion
Cellular therapies available
1.Ex vivo T cell expansion
Advantages: not restricted by HLA type, small blood volume required, naive donor can be used, generation of polyclonal T cells.
Disadvantages: extensive culture period, seropositive donors required.
2. Direct selection
PMHC multimer
Advantages : no needed extensive ex vivo manipulation and undergo rapid expansion in vivo.
Disadvantages: restricted by HLA type, seropositive donors
Cytoquine capture
Advantages: no needed extensive ex vivo manipulation and undergo rapid expansion,not restricted by HLA type
Disadvantages: require seropositive donors and large volume of blood.
3. Genetically engineered cells
Advantages: recognize antigens in a HLA independent manner, target conserved and essential epitopes.
Disadvantages: expensive, only surface antigens can be targeted, restricted by epitope.
Limitations
Deficiency of T cell differentiation.
Lifelong immunosuppression.
The role of adoptive immunotherapy
The adoptive transfer of CMV specific T cells is widely used and applied in hematopoietic stem cell transplant.
They may help to restore the CMV specific immunity for preventing infection in addition to serve as a treatment for CMV infection in SOT who don’t respond to conventional therapies such as infection with antiviral resistant strains.
During the last decade, many studies have demonstrated the role of CMV specific T-cell immune response on controlling CMV replication and dissemination. In fact, it is well established that transplanted patients lacking CMV-specific T-cell immunity have an increased occurrence of CMV replication episodes and CMV-related complications. In this context, the use of adoptive transfer of CMV-specific T-cells has been widely investigated and applied to Hematopoietic Stem Cell Transplant patients and may be useful as a therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia in patients receiving a transplantation.
In the context of transplantation, CMV-specific T-cell transfer has been widely investigated and applied to Hematopoietic Stem Cell Transplant (HSCT) patients, both prophylactically, to reconstitute protective antiviral immunity, and as a treatment in patients with refractory CMV infection . The most ambitious study carried out to date in SOT , was performed in a cohort of 21 SOT recipients (13 kidney, 8 lung and 1 heart) who developed recurrent ganciclovir resistant CMV infections. Thirteen of these patients (8 D+/R-, 3 D+/R+ and 2 D-/R-) were subjected to T-cell (ranging from 22.2-245 × 106 T-cells) adoptive transfer receiving a maximum of 6 doses one of which discontinued therapy after a single dose. Adverse events attributable to T-cell infusion were grade 1 or 2 (fatigue and malaise) with no adverse events associated with a change in the graft status. Eleven of the 13 showed objective improvement in their symptoms including a reduction (with a median drop of 1.2 × 103 CMV copies/mL) or resolution of CMV reactivation and resolution of CMV disease symptoms. In addition, the use of antiviral drug therapy was either completely stopped (in 5 of 11 patients) or significantly reduced (in 6 of 11patients). Evidences of immunological reconstitution was associated with control of viremia.
CELLULAR THERAPIES AVAILABLE
A) Ex vivo T-cell expansion requires the in vitro stimulation and expansion of T-cells using APCs presenting viral peptides or proteins.
(B) Direct selection employs virus-derived peptide specific multimers in the setting of a HLA class-I molecule, viral antigen T-cell stimulation followed by cytokine expressing T-cell selection using antibody coated immunomagnetic beads or activation marker selection based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation.
(C) Genetic manipulation requires gene transfer of high affinity CMV-specific T-cell receptors (TCR) or chimeric-antigen receptors (CAR) to change specificity of T-cells to CMV antigens. T
Cell Therapy Limitations and Alternatives in SOT Patients-
A).in vitro generated CMV -specific CTL are highly sensitive to immunosuppressive drugs (such as cyclosporin A and FK506) impairing the production of effector cytokines .
B)Another limitation is associated with deficiencies of T-cell differentiation in SOT recipients receiving immunosuppression.
C)Infusion of donor derive T-cells from donors may also transfer alloreactive T cells in numbers sufficient that could trigger episodes of rejection, particularly if the donor and the host differ in one or more HLA alleles
FUTURE DIRECTIONS AND PERSPECTIVES
The role of CMV-specific T-cell immune reconstitution after SOT have demonstrated several benefits, including lower risk of CMV infection and graft rejection. Thus, the development and improvement of new CMV-specific T-cell transfer based therapies could be a useful to adjust the therapeutic interventions . However, despite the increasing interest on adoptive CMV specific T-cell transfer, most of the information available comes from studies in HSCT recipients Only few reports including a small number of SOT recipients have used Tcell adoptive immunotherapy as a treatment of CMV infection or disease.Although promising results were obtained, further development have been limited due to difficulties of Tcell expansion in SOT that are receiving immunosuppressive regimens, and the risk of graft rejection after T-cell administration. .
Conclusion
Recent studies have significantly increased our knowledge about the protective role of CMV-specific T-cell immune response against CMV infection and disease. And thus the use of T-cell adoptive therapy may help to restore the CMV-specific immunity for preventing CMV infection in addition to serve as a treatment for CMV infections in SOT individuals who do not respond to conventional therapies, such as patients infected with antiviral resistant strains with no alternative treatment available.
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation
1. EBV-associated PTLD that persists following initial therapy
2.Resistant cases of CMV
3.BK virus Nephropathy
4.EBV virus infection
INTRODUCTION
Viral infection, including cytomegalovirus (CMV), BK virus and Epstein-Barr virus, remains a major cause of morbidity and mortality in immunocompromised individuals (1–5). While in immunocompetent individuals latent CMV infection is controlled by the immune system (6), in transplant recipients, both hematopoietic stem cell (HSCT) and solid organ transplantation (SOT), CMV infection is one of the main infectious complications.
Although the antiviral drugs to treat CMV infection have highly improved during the years, there are still some issues associated with the use of the available antivirals (ganciclovir, foscarnet, cidofovir and more recently letermovir) such as undesirable side effects (nephrotoxicity) and selection of resistance mutations in addition to the high cost.
T-Cell Expansion
To successfully generate and expand CMV-specific T-cells, it is crucial to define the most immunogenic epitopes used by the antigen presenting cells (APC) to promote the activation and proliferation of peptide-specific T-cells.
Direct Selection Using Cytokine Capture System (CCS)
CMV-specific T-cells can also be selected using IFN-g cytokine capture system (CCS), a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral antigens.
This strategy allows T-cell selection that in contrast with pMHC has no HLA restriction and as an additional benefit, stimulating and capturing a polyclonal population of CD4+ and/or CD8+ T-cells depending on the antigen used for stimulation, not achieved using the Streptamer strategy. Different authors have successfully isolated functional CMV-specific T-cells using this method.
Cell Therapy Limitations and Alternatives in SOT Patients
The intensity and long-term immunosuppression requirement to prevent allograft rejection pre-disposes SOT recipients to a wide range of viral complications (1). In addition, antiviral treatment can generate side effects such as nephrotoxicity (99), and the selection of drug resistant mutant CMV strains (100), limiting treatment capability in SOT recipients. Based on these limitations, cell therapy may be an appropriate and effective alternative antiviral treatment. However, as pointed out previously, deficiencies in T-cell differentiation and lifelong immunosuppression can affect to long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipients (76). Here, we analyze the alternatives available to overcome these limitations.
Conclusion
Recent findings regarding the development of new techniques to select, isolate and enrich functional CMV-specific T-cells and the possible generation of third-party donor cell banks may help to use CMV-specific adoptive transfer as an alternative therapy for SOT recipients. However, further work is clearly needed in order to fully understand and assess the clinical utility of these techniques in SOT recipients.
1. Please summarize this article.
Introduction:
CMV infection is the main complication in both HSCT and SOT.
There’s is role of CMV specific T-cell immune response on controlling CMV replication and dissemination.
CMV specific T cell response can control replication and dissemination of the virus, ultimately eliminating it.
USE OF ADOPTIVE TRANSFER OF CMV[1]SPECIFIC T-CELLS IN THE CONTEXT OF SOLID ORGAN TRANSPLANTATION:
The use of CMV-specific T-cell adoptive transfer is currently being evaluated for clinical application, with promising results as a treatment for CMV infection and disease in ulcerative enteritis in primary immunodeficiency or in pediatric retinitis caused by CMV. the use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment.
CELLULAR THERAPIES AVAILABLE:
I. T-Cell Expansion: requires the in vitro stimulation and expansion of T-cells using APCs presenting viral peptides or proteins.
II. Direct selection: Employs virus-derived peptide specific multimers in the setting of a HLA class-I molecule, viral antigen T-cell stimulation followed by cytokine expressing T-cell selection using antibody coated immunomagnetic beads or activation marker selection based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation.
III. Genetic manipulation: Requires gene transfer of high affinity CMV-specific T-cell receptors (TCR) or chimeric-antigen receptors (CAR) to change specificity of T-cells to CMV antigens.
Advantages:
Ex- vivo expansion:
1) Not restricted by HLA type.
2) small blood volume required.
3) naïve donor can be used.
4) generation of polyclonal T-cells.
Direct Selection:
No needed extensive ex vivo manipulation and undergo rapid expansion in vivo.
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR):
§ Rapid detection and enrichment of T-cells; broader repertoire of antigen-specific T-cells
§ Compatible with other assay formats; not restricted by HLA
§ not needed previous information of immunodominant epitopes
§ no specialized APC such as dendritic cells are needed
CONCLUSIONS:
According to current evidence showed promising result with the protective role of CMV specific T-cell immune response against CMV infection resistant to other antivirals.
2. Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation:
Introduction:
CMV is one of the most infections of transplant patients and associated with increase morbidity and mortality and decrease survival rate.
Over 75% of SOT patients are newly infected or activate latent infection after transplantation.
Definitions:
CMV infection: detection of CMV in the blood by culture, antigen test or PCR.
CMV syndrome: detection of CMV in the blood with symptoms.
CMV disease: detection of CMV by culture or histology in affected organs.
All organ donors and recipients should be screened for CMV (IgG antibody) serostatus prior to, or at the time of transplantation.
CMV Prophylaxis:
By given valganciclovir prophylaxis to people receiving kidney and liver transplants for at least 3 months following transplantation if either:
1) The recipient is seronegative for CMV and receives an allograft from a CMV seropositive donor (D+/R-)
2) The recipient has received T-lymphocyte depletion therapy with Antithymocyte gobulin (ATG) or Alemtuzumab (Campath ), where donor: recipient serostatus is D+/R+ or D-/R+.
Valganciclovir prophylaxis given for people receiving heart, lung, intestinal or pancreas transplants for at least 3 months following transplantation if either:
1) The recipient is seronegative for CMV and receives an allograft from a CMV seropositive donor (D+/R-) [1C] OR
2) The recipient has received T-lymphocyte depletion therapy with Antithymocyte gobulin (ATG) or Alemtuzumab (Campath ), where donor: recipient serostatus is D+/R+ or D-/R+ [1C]
Do not routinely give Valganciclovir prophylaxis if donor and recipient are seronegative for CMV (D-/R-).
Administer Valganciclovir prophylaxis for at least 3 months after starting treatment for acute allograft rejection if either donor or recipient are CMV positive (D+/R-, D+/R+ or D-/R+.
Laboratory Testing for CMV:
By Quantitative Nucleic Acid Testing (QNAT) of whole blood or plasma to quantify CMV viral load.
Monitoring for CMV Infection and Disease:
Full Blood Count should be monitoring at least every 2 weeks whilst on Valganciclovir [1A].
Consider switching to CMV monitoring and pre-emptive therapy if people develop side effects e.g.; neutropenia, on Valganciclovir [1C].
Treating CMV Infection and Disease:
There is strong evidence to recommend a minimum 2 week course of oral valganciclovir for treatment of CMV infection and disease
CMV viral load should be checked after 2 and 3 weeks and treatment should only be discontinued when symptoms have resolved and there are 2 consecutive CMV virus titres below the locally-agreed threshold (the evidence for this recommendation is less robust).
Ganciclovir resistance:
Develop by many risk factors which include:
A) prolonged course or subtherapeutic doses of anti-viral medication
B) D+/R-
C) intensive immunosuppression e.g. T-cell depleting agent.
D) lung transplant recipients.
When ganciclovir resistance is proven, stop ganciclovir or valganciclovir and offer Foscarnet treatment as an alternative.
Immunosuppression dose reduction:
For adults, children and young people who develop CMV infection or disease (with or without leukopenia) following solid organ transplantation:
1) Consider a dose reduction of either calcineurin inhibitor or mycophenolate mofetil / azathioprine [1C].
2) Discuss with patients, and, where appropriate, parents or carers, the risk of acute rejection with immunosuppression dose reduction [1D].
3) Review the dosing of immunosuppression following resolution of CMV infection or disease [1D].
Information, education and support:
Appropriate patient counselling is important including helping SOT recipients understand their individualized risk profile based upon donor/recipient CMV serostatus and immunosuppression used.
CONCLUSIONS
Recent studies have significantly increased our knowledge about the protective role of CMV-specific T-cell immune response against CMV infection and disease. And thus the use of T-cell adoptive therapy may help to restore the CMV-specific immunity for preventing CMV infection in addition to serve as a treatment for CMV infections in SOT individuals who do not respond to conventional therapies, such as patients infected with antiviral resistant strains with no alternative treatment available. Recent findings regarding the development of new techniques to select, isolate and enrich functional CMV-specific T-cells and the possible generation of third party donor cell banks may help to use CMV-specific adoptive transfer as an alternative therapy for SOT recipients. However, further work is clearly needed in order to fully understand and assess the clinical utility of these techniques in SOT recipients.
Introduction;
-Viral infection, including cytomegalovirus (CMV), BK virus and Epstein-Barr virus, remains a major cause of morbidity and mortality in immunocompromised individuals.
-The incidence of CMV reactivation/reinfection in SOT is 16–56% , while in HSCT has been reported to be 30–70%.
-Cell mediated immune response is considered the most important arm of the immune system against CMV infection with increasing evidences demonstrating a role of CMV-specific T-cells in protecting from infection, which can contribute to improve clinical care after transplantation.
Strategies for the generation of CMV-specific T-cells.
Ex vivo T-cell expansion requires the in vitro stimulation and expansion of T-cells using APCs presenting viral peptides or proteins.
Direct selection employs virus-derived peptide specific multimers in the setting of a HLA class-I molecule, viral antigen T-cell stimulation followed by cytokine expressing T-cell selection using antibody coated immunomagnetic beads or activation marker selection based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation
.
Genetic manipulation requires gene transfer of high affinity CMV-specific T-cell receptors (TCR) or chimeric-antigen receptors (CAR) to change specificity of T-cells to CMV antigens
Cell Therapy Limitations and Alternatives in SOT Patients:
Deficiencies in T-cell differentiation and lifelong immunosuppression can affect to long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipients., can be overcome by:
Adoptive immunotherapy can be used for prophylaxis and treatment of not only CMV, but also BKV, and PTLD. EBV can also be targeted using this method. Refractory infections and recurrent leukemia can specifically be treated using adoptive immunotherapy in solid organ transplant recipients and hematopoietic stem cell transplant recipients.
Introduction:
There’s is role of CMV specific T-cell immune response on controlling CMV replication and dissemination.
The use of adoptive transfer of CMV-specific T-cell may be useful as a therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia in patients receiving a transplantation.
USE OF ADOPTIVE TRANSFER OF CMVSPECIFIC T-CELLS IN THE CONTEXT OF
SOLID ORGAN TRANSPLANTATION:
The use of CMV-specific T-cell adoptive transfer is currently being evaluated for clinical application, with promising results as a treatment for CMV infection and disease in ulcerative enteritis in primary immunodeficiency or in pediatric retinitis caused by CMV. the use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment.
CELLULAR THERAPIES AVAILABLE:
T-Cell Expansion:
Different approaches:
ICMV-specific CD8+ T-cell clones were generated by stimulating donor peripheral blood mononuclear cells (PBMC) with CMV-infected fibroblasts.
Discontinued risk of producing infection in patients.
Later, CMV lysates or pp65-NLV peptide were used to stimulate CMV-specific T-cells.
Using the pp65-NLV peptide only stimulated adoptive immunity against a single viral epitope and its application may be limited for HLA-A2 patients/donors . To overcome this problem, “poly.specific” products targeting multiple antigens were generated.
Direct Selection Using Specific Peptide–MHC (pMHC) :
Using pMHC multimers allows to isolate T-cells based on the Tcells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules.
Direct Selection Using Cytokine Capture System (CCS) :
CMV-specific T-cells can also be selected using IFN-g cytokine capture system (CCS), a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral antigens.
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR):
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR) .
is the gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR).
The generation of autologous CAR T-cells which has also been explored as immunotherapy against CMV enables antigen recognition in a MHC independent manner and can be designed to specifically target conserved and essential epitopes of the selected antigen overcoming pathogen escape mechanisms. .
Cell Therapy Limitations and Alternatives in SOT Patient:
Limitation:
Deficiencies in T-cell differentiation and lifelong immunosuppression can affect to long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipient.
Solution:
Genetically modify the in vitro generated CTL to confer resistance to these drugs.
Decreasing patient´s immunosuppression during a period post-infusion.
Use of third-party CMV-specific Tells.
Another limitation:
Is associated with deficiencies of T-cell differentiation in SOT recipients receiving immunosuppression.
Solution:
Promote the generation of CD8+ and CD4+ T-cells displaying multiple poly functional effector functions.
Limitation:
Infusion of donor derive T-cells alloreactive T cells in numbers sufficient that could trigger episodes of rejection.
Solution:
Is to extensive culturing T cells or even establishing T-cell clones to eradicate alloreactive T cells.
Third-party cell banks:
The creation of third-party cell banks as well as third party donor registries has emerged as a new
Possibility of treatment that employs T-cells derived from partially HLA-matched third party donors.
Such banks permit selection of T-cells on the basis of HLA allele phenotype, viral specificity and HLA restriction, which may provide distinct advantages, particularly in the treatment of HLA non-identical recipient.
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation:
The use of T-cell adoptive therapy may help to restore the CMV-specific immunity for preventing CMV infection in addition to serve as a treatment for CMV infections in SOT individuals who do not respond to conventional therapy ,such as patients infected with antiviral resistant strains with no alternative treatment available.
Summary
Introduction
This article is relating CMV specific T cell transfer as a treatment for infection in solid organ transplant recipients. CMV specific T cell response can control replication and dissemination of the virus, ultimately eliminating it.
Discussion
Application of this method targeting CMV infection has been done in hematopoietic stem cell transplants as a form of treatment as well as prophylaxis, with good results. It can also be used in patients who are refractory to CMV treatment.
The reason this has not been tried widely in solid organ transplants is because IS regimen in these patients often suppresses T cell response effectively.
Different methods available include direct section and genetically engineered cells. Both have different advantages and disadvantages. For instance, ex vivo expansion or direct selection method requires seropositive donors and extensive culture period with one type needing large blood volumes while genetically engineered cells can demand more labour and even more time with restricted targets such as only surface antigens.
The first attempt at this method in SOT recipients was done in a lung transplant recipient who was resistant to ganciclovir and foscarnet in the treatment of resistant persistent CMV pneumonia. Although the patient improved initially, with observed reduction in viral land and symptoms of pneumonia, the patient’s condition worsened within a month (patient was still CMV positive), later resulting in death due to graft failure, but negative for CMV.
Since then, several trials have been conducted on SOT recipients with this method, especially with donor cell banks, and improvements have been made. Adverse events were minimal, with fatigue and malaise predominating as patient complaints. Graft status remained unaffected. Many patients have had their infection resolve with completion of antiviral therapy.
However, there are limitations that have been observed so far. One major limitation is the deficiency of T cell differentiation in SOT recipients receiving IS drugs. This can be allayed by finding methods to promote the generation of CD8+ and CD4+ T cells displaying multiple polydunctional effector functions so that CMV infection can be controlled effectively.
Conclusion
Although there is space for improvement, with further research being needed in this area, the use of CMV specific T cell adoptive transfer has shown good promise in treating infection in SOT recipients, especially when the infection is persistent or resistant to treatment, and with other options being limited.
Role of adoptive immunotherapy in transplantation
Adoptive immunotherapy can be used for prophylaxis and treatment of not only CMV, but also BKV, and PTLD. EBV can also be targeted using this method. Refractory infections and recurrent leukemia can specifically be treated using adoptive immunotherapy in solid organ transplant recipients and hematopoietic stem cell transplant recipients.
1. Please summarise this article.
Introduction:
Antivirals (ganciclovir, foscarnet, cidofovir, letermovir) have been the main stay of therapy for CMV infection post-transplant but associated with undesirable side effects (nephrotoxicity, bone marrow suppression, neuropathy, seizure) and development of resistance, in addition to high cost.
Cell mediated immune response is considered the most important arm of the immune system against viral infections. Transplanted patients lacking CMV-specific T-cell immunity have an increased occurrence of CMV replication episodes and CMV-related complications.
In this context, the use of cellular therapy may be useful to reconstitute the CMV specific T-cell response and to control CMV viremia in SOT recipients.
In last decade, many studies have demonstrated the role of CMV specific T-cell immune response on controlling CMV replication and dissemination.
Use of adoptive transfer of CMV-specific T-cells has been widely investigated and applied to HSCT patients and may be useful as a therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia in patients receiving a transplantation. Only few authors have explored the use of T-cell adoptive transfer in SOT recipients.
This review article provides a synthesis of recent data regarding the impact of using CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients – the different approaches to stimulate, isolate and expand CMV-specific T-cells developed over the years and a discussion of the possible use of CMV adoptive cellular therapy in SOT population.
CELLULAR THERAPIES AVAILABLE: Strategies to generate CMV-specific T-cells.
(A) T-cell expansion ex-vivo
– Involves in vitro stimulation and expansion of T-cells using APCs presenting viral proteins or peptides
– Crucial to define the most immunogenic epitopes used by the APC to promote the activation and proliferation of peptide-specific T-cells
– IE-1 and pp65 proteins are two of the most immunodominant CMV antigen
– CMV lysates or pp65-NLV peptide used to stimulate CMV-specific T-cells
– “poly-specific” products targeting multiple antigens were generated by incubating allogeneic T-cells in vitro with clusters of 15-mer peptides spanning the entire pp65 antigen to generate CMV-specific oligoclonal T-cells.
– Adoptive transfer of the oligoclonal T-cells were able to eliminate viremia, and infused cells persisted for up to two years.
– The improvement of the methodology for ex vivo expansion has reduced the presence of alloreactive or naive T-cells in the final product
(B) Direct selection
Direct Selection Using Specific Peptide–MHC (pMHC)
– HLA-peptide tetramers from pp65 and IE-1 proteins have been used to select CD8+ T-cells that were further isolated using magnetic beads
Streptamer technology
– reduces the time and improve the quality of the final product, minimizing alloreactivity
– isolates CD8+ T-cells from CMV seropositive donors, demonstrating both immune reconstitution, as well as antiviral safety and efficacy after HSCT
– using partially HLA-matched CMV-specific T-cells obtained from a third party donor has shown to be safe to treat CMV infection in SOT patients,
Direct Selection Using Cytokine Capture System (CCS)
– viral antigen T-cell stimulation followed by cytokine expressing T-cell selection using antibody coated immunomagnetic beads
– CMV-specific T-cells can also be selected using IFN-g cytokine capture system (CCS), a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral antigens
– Other selection strategy is to isolate and enrich activated viral-specific T-cells after antigen stimulation based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation, e,g CD137
C. Genetic manipulation
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
– based on the gene modification of patient’s lymphocytes with CMV-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR)
– to change specificity of T-cells to CMV antigens
Advantages:
Ex- vivo expansion
– Not restricted by HLA type
– small blood volume required
– naïve donor can be used
– generation of polyclonal T-cells
Direct Selection
– No needed extensive ex vivo manipulation and undergo rapid expansion in vivo
Genetically engineered cells
– Rapid detection and enrichment of T-cells; broader repertoire of antigen-specific T-cells
– Compatible with other assay formats; not restricted by HLA
– not needed previous information of immunodominant epitopes
– no specialized APC such as dendritic cells are needed
2. Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
· CMV infections – GCV-resistant; recurrent and refractory to antiviral therapy
· PTLD – refractory to Retuxi + Chemo-immunotherapy
· Lymphoma (NHL)
· EB Virus infection
· BK Virus diseases
Introduction;
. Post-transplant viral infection has been the major cause of morbidity and mortality. In all recipient with SOT and with HSCT transplantations viral infection were the main complication.
CMV seropositive recipients are more vulnerable to recurrent and super infection, the incidence of CMV reactivation/ reinfection in SOT is 16 to 56% with a median value of 30%, while in HSCT it is around 30 to 70%.
There are two main mechanism of graft dysfunction secondary to CMV infection, CMV proliferation causing viremia, syndrome, and invasive disease, secondly, this indirectly causing graft rejection by immunomodulation.
The cell mediated immune response is the first and most effective defense mechanism against CMV infection.
During recent years the antiviral therapy has improved the graft survival, with some unwanted side effects.
In this context the use of cellular therapy may be useful against CMV infection in SOT, where patients are immunocompromised, so the use of adaptive cellular therapy would be a hope in reactivation/ resistant cases of CMV patients.
Use of Adaptive specific T-cell therapy in SOT;
. It was widely investigated and currently being used for resistant and reactivation of CMV disease.
The procedure is CMV specific T-cells total two infusions with two weeks apart.
Cellular therapies available;
. The strategies are ex vivo T cell culture, with advantage of no restriction by HLA type.
T-cell expansion are epitopes pp65, IE-1, used by APC to activate and proliferate CMV-peptide specific T-cells.
In direct selection of using specific peptide MHC based on TCR ability to bind a complex mixture of peptide loaded recombinant of HLA molecules.
By direct selection using cytokine capture system with rapid assay that allows to select CD4 and CD8 inf gamma secreting T-cells.
No HLA restriction.
The gene modification of recipient T-cell with tumor specific T-cell receptors by T- cell generation using activation marker and engineered T-cells.
Cell therapy limitation and alternatives in SOT patients;
. Selection of drug resistant mutant CMV strain,
Nephrotoxicity,
Deficiencies in T-cell differentiation and lifelong immunosuppression can affect long term survival of the transfused cells,
Predisposition of variety of infections.
Conclusion;
. According to current evidence showed promising result with the protective role of CMV specific T-cell immune response against CMV infection resistant to other antivirals.
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation;
. Treatment of BK virus, CMV, PTLD, and for rejection.
Introduction:
Strategies for the generation of CMV-specific T-cells.
(A) Ex vivo T-cell expansion requires the in vitro stimulation and expansion of T-cells using APCs presenting viral peptides or proteins.
(B) Direct selection employs virus-derived peptide specific multimers in the setting of a HLA class-I molecule, viral antigen T-cell stimulation followed by cytokine expressing T-cell selection using antibody coated immunomagnetic beads or activation marker selection based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation
.
(C) Genetic manipulation requires gene transfer of high affinity CMV-specific T-cell receptors (TCR) or chimeric-antigen receptors (CAR) to change specificity of T-cells to CMV antigens
Advantage:
Ex- vivo expansion
No restricted by HLA type
small blood volume required
naïve donor can be used
generation of polyclonal T-cells
Direct Selection
No needed extensive ex vivo manipulation and undergo rapid expansion in vivo
Genetically engineered cells
Rapid detection and enrichment of T-cells; broader repertoire of antigen[1]specific T-cells; Compatible with other assay formats; not restricted by HLA;
not needed previous information of immunodominant epitopes;
no specialized APC such as dendritic cells are needed
Adoptive immunotherapy in managing different conditions related to transplantation
Management of BK Virus, CM Virus, PTLD and rejection
Introduction :
CMV infection is a major cause of morbidity and mortality in immunocompromised individuals, with CMV seropositive HSCT patients presenting the highest risk of recurrent infections.
CMV infection can increase the risk of graft rejection and decreased recipient survival. Cellular therapy may be useful to rebuild the T-cell response and control CMV viremia in SOT recipients.
USE OF ADOPTIVE TRANSFER OF CMV SPECIFIC T-CELLS IN THE CONTEXT OF SOLID ORGAN TRANSPLANTATION
CMV-specific T-cell transfer has been widely investigated and applied to Hematopoietic Stem Cell Transplant (HSCT) patients, both prophylactically, and as a treatment in patients with refractory CMV infection
In SOT recipients it has been less investigated probably due to the T-cell response attenuation produced by the administration of the immunosuppressive therapy.
The patient received 2 infusions (1.9 x 107 T cells/infusion) 2 weeks apart, with no side effects and with low CMV titers during two months after which a relapse of the viral load occurred.
The most ambitious study carried out to date was performed in a cohort of 21 SOT recipients (13 kidney, 8 lung and 1 heart) who developed recurrent ganciclovir resistant CMV infections.
CELLULAR THERAPIES AVAILABLE:
During the last years a better understanding of the CMV-specific T-cell immunology such as the conserved T-cell epitopes ,has led to the improvement of the methods for ex vivo T-cell culture .
In addition, rapid tests to evaluate the effector function of the CMV-specific T-cells have become available.
T-Cell Expansion
To successfully generate and expand CMV-specific T-cells, it is crucial to define the most immunogenic epitopes used by the antigen presenting cells (APC) to promote the activation and proliferation of peptide-specific T-cells .
IE-1 and pp65 proteins are two of the most immunodominant CMV antigens and have been widely used to stimulate the CMV-specific immune response .
T-cell ex vivo stimulation and expansion requires a small blood volume to establish the T-cell culture, making possible the generation of CMV-specific T-cells from low levels of circulating T-cells and naive donor sources.
Direct Selection Using Specific
Peptide–MHC (pMHC)
HLA peptide tetramers from pp65 and IE-1 proteins have been previously used to select CD8+ T-cells that were further isolated using magnetic beads .However, the main disadvantages of this technique are related with the limitation of the method to isolate only CD8+ or CD4 T-cell populations, and the irreversibility of the binding .
The Streptamer technology has been used to isolate CD8+ T-cells from CMV seropositive donors, demonstrating both immune reconstitution and antiviral safety and efficacy after HSCT. However, the selected T-cells are limited by the HLA restriction imposed by the Streptamer, limiting its use for adoptive therapy.
Direct Selection Using Cytokine Capture System (CCS)
CMV-specific T-cells can also be selected using IFN-g cytokine capture system (CCS), this strategy allows T-cell selection that in contrast with pMHC has no HLA restriction and as an additional benefit, stimulating and capturing a polyclonal population of CD4+ and/or CD8+ T-cells depending on the antigen used for stimulation, not achieved using the Streptamer strategy.
Another selection strategy is to isolate and enrich activated viral specific T-cells after antigen stimulation based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation, such as CD25, CD69, CD137 and CD154 .
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
The generation of autologous CAR T-cells which has also been explored as immunotherapy against CMV , CAR-T-cell therapy identifies exclusively antigens located in the cell surface, TCR can also recognize intracellular antigenic fragments presented by MHC molecules .
Cell Therapy Limitations and Alternatives in SOT Patients
The intensity and long-term immunosuppression requirement to prevent allograft rejection pre-disposes SOT recipients to a wide range of viral complications .Based on these limitations, cell therapy may be an appropriate and effective alternative antiviral treatment.
However, as pointed out previously, deficiencies in-cell differentiation and lifelong immunosuppression can affect long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipients .
FUTURE DIRECTIONS AND PERSPECTIVES
Although promising results were obtained, further development have been limited due to difficulties of T Cell expansion in SOT that are receiving immunosuppressive regimens, and the risk of graft rejection after T-cell administration.
Results from the ongoing clinical trial analyzing the safety and feasibility of administering CMV specific- CTLs from haploidentical donors in transplant patients would be of importance to implement T-cell adoptive therapy in SOT recipients.
CONCLUSIONS
The use of T-cell adoptive therapy may help to restore the CMV-specific immunity for preventing CMV infection in addition to serving as a treatment for CMV infections in SOT individuals who do not respond to conventional therapies.
Possible generation of third party donor cell banks may help to use CMV-specific adoptive transfer as an alternative therapy for SOT recipients.
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
–In treatment and prevention of CMV ,BK virus nephropathy PTLD and rejection
Reference :
Hemasphere. 2019 Jun; 3(Suppl ): 74-77. Published online 2019 Jun 30. doi: 10.1097/HS9.0000000000000226
Introduction:
There’s is role of CMV specific T-cell immune response on controlling CMV replication and dissemination.
the use of adoptive transfer of CMV-specific T-cell may be useful as a therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia in patients receiving a transplantation.
USE OF ADOPTIVE TRANSFER OF CMVSPECIFIC T-CELLS IN THE CONTEXT OF
SOLID ORGAN TRANSPLANTATION
The use of CMV-specific T-cell adoptive transfer is currently being evaluated for clinical application, with promising results as a treatment for CMV infection and disease in ulcerative enteritis in primary immunodeficiency or in pediatric retinitis caused by CMV. the use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment.
CELLULAR THERAPIES AVAILABLE:
T-Cell Expansion:
Different approaches:
ICMV-specific CD8+ T-cell clones were generated by stimulating donor peripheral blood mononuclear cells (PBMC) with CMV-infected fibroblasts.
Discontinued risk of producing infection in patients.
Later, CMV lysates or pp65-NLV peptide were used to stimulate CMV-specific T-cells.
Using the pp65-NLV peptide only stimulated adoptive immunity against a single viral epitope and its application may be limited for HLA-A2 patients/donors . To overcome this problem, “poly.specific” products targeting multiple antigens were generated.
Direct Selection Using Specific Peptide–MHC (pMHC) :
Using pMHC multimers allows to isolate T-cells based on the Tcells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules.
Direct Selection Using Cytokine Capture System (CCS) :
CMV-specific T-cells can also be selected using IFN-g cytokine capture system (CCS), a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral antigens.
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR) .
is the gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR).
The generation of autologous CAR T-cells which has also been explored as immunotherapy against CMV enables antigen recognition in a MHC independent manner and can be designed to specifically target conserved and essential epitopes of the selected antigen overcoming pathogen escape mechanisms. .
Cell Therapy Limitations and Alternatives in SOT Patient:
Limitation:
Deficiencies in T-cell differentiation and lifelong immunosuppression can affect to long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipient.
Solution:
Genetically modify the in vitro generated CTL to confer resistance to these drugs.
Decreasing patient´s immunosuppression during a period post-infusion.
Use of third-party CMV-specific Tells.
Another limitation:
Is associated with deficiencies of T-cell differentiation in SOT recipients receiving immunosuppression.
Solution:
Promote the generation of CD8+ and CD4+ T-cells displaying multiple poly functional effector functions.
Limitation:
Infusion of donor derive T-cells alloreactive T cells in numbers sufficient that could trigger episodes of rejection.
Solution:
Is to extensive culturing T cells or even establishing T-cell clones to eradicate alloreactive T cells.
Third-party cell banks
The creation of third-party cell banks as well as third party donor registries has emerged as a new
Possibility of treatment that employs T-cells derived from partially HLA-matched third party donors.
Such banks permit selection of T-cells on the basis of HLA allele phenotype, viral specificity and HLA restriction, which may provide distinct advantages, particularly in the treatment of HLA non-identical recipient.
the use of T-cell adoptive therapy may help to restore the CMV-specific immunity for preventing CMV infection in addition to serve as a treatment for CMV infections in SOT individuals who do not respond to conventional therapy ,such as patients infected with antiviral resistant strains with no alternative treatment available.
1. Please summarise this article.
The article deals with role of CMV-specific T cell adoptive transfer in CMV infected transplant recipients.
Introduction: Cytomegalovirus (CMV) is one of the main infection seen in transplant recipients, with maximum risk in CMV seropositive hematopoietic stem cell transplant (HSCT) recipients. CMV reactivation in solid organ transplant (SOT) is 16-56% while in HSCT, it is 30-70%. CMV infection causes direct effect on different organs (gastroenteritis, retinitis, encephalitis etc), as well as indirect effects like graft rejection, poor recipient survival, and opportunistic infections. CMV specific T cells protect from CMV infection. Antivirals used to treat CMV are associated with high costs, undesirable side effects, and resistance mutations. So, cellular therapy may be useful to control CMV viremia in SOT recipients.
Use of adoptive transfer of CMV specific T cells in SOT: It has been shown to be useful in treatment for CMV infection and disease in pediatric CMV retinitis, and ulcerative colitis in primary immunodeficiency. CMV-specific T-cell therapy has been used extensively in HSCT, but less evaluated in SOT (probably due to less tolerance to donor-derived cytolytic T lymphocytes). It has been tried in lung, kidney and heart transplants, with none of the patients showing any severe adverse effects. The studies suggest that CMV-specific T-cell adoptive transfer has role in SOT patients with limited options for CMV treatment.
Cellular therapies available: Improvement in methods for ex-vivo T-cell culture, and availability of rapid tests to evaluate effector function of CMV-specific T-cells has led to better understanding of their immunology. Strategies for T-cell generation include ex-vivo T cell expansion (using antigen presenting cells, APCs presenting viral peptides or proteins), Direct selection (using specific peptide MHC, using interferon gamma cytokine capture system, CCS, or using activation markers like CD25, CD69, CD137, and CD154), or using genetically engineered cells (gene transfer of high affinity CMV-specific T-cell receptors, TCR, and chimeric antigen receptors, CAR). Each of the methodology has its ow advantages and disadvantages. Ex vivo expansion requires seropositive donors, and takes prolonged time. Direct selection reduces time, increases quality, and decreases alloreactivity, but requires large blood volume. Genetic engineering is costly and MHC restricted.
Cell therapy limitations and alternatives in SOT patients: Cell therapy may be appropriate treatment option due to side effects of and resistance to antiviral therapies, but long-term immunosuppression affects long-term survival of transfused cells. Invitro CMV-specific cytotoxic T lymphocytes are highly sensitive to immunosuppressives like cyclosporine and tacrolimus, and hence require genetic modification to prevent being affected by the immunosuppressives, reduction in immunosuppressive dose in post-infusion period, or use of third party CMV-specific T-cells. T cell differentiation is deficient in SOT recipients, which would require efforts to promote generation of CD8+ and CD4+ T cell showing multiple polyfunctional effector functions. Infusion may transfer alloreactive T cells leading to episodes of rejection, it can be averted by extensive T-cell culturing. Third party cell banks and third party registries, offering multiple viral epitopes, help in getting rapid “off the shelf” products for a large number of patients.
Conclusion: CMV specific T cell immune reconstitution has shown lower risk of CMV infection and graft rejection, help to restore CMV specific immunity, and help in treating individuals resistant to conventional anti-CMV treatment.
2. Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
Adoptive immunotherapy has been shown to be useful in SOT patients with refractory CMV infection, HSCT patients with recurrent leukemia, in graft versus host disease, and against disease caused by other viral infections like adenovirus, BK virus etc.
CMV infection in SOT is one of major cause of morbidity and even mortality. The emergence of Ganciclovir resistance has further complicated the issue.
The concept of CMV specific adaptive T cell transfer looks fascinating to overcome this issue and has been widely investigated and applied to Hematopoietic Stem Cell Transplant patients and may be useful as a therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia in patients receiving a transplantation.
In contrast, in SOT recipients it has been less investigated probably due to the T-cell response attenuation produced by the administration of the immunosuppressive therapy. In addition, SOT recipients may not tolerate donor-
derived cytolytic T lymphocytes (CTLs) due to the activation of cytokine-mediated stimulation of the alloreactive T-cells causing direct alloimmune injury.
And thus the use of T-cell adoptive therapy may help to restore the CMV-specific
immunity for preventing CMV infection in addition to serve as a treatment for CMV infections in SOT individuals who do not respond to conventional therapies, such as patients infected with antiviral resistant strains with no alternative treatment available. Recent findings regarding the development of new techniques to select, isolate and enrich functional CMV-specific T-cells and the possible generation of third party donor cell banks may help to use CMV-specific adoptive transfer as an alternative therapy for SOT recipients. However, further work is clearly needed in order to fully understand and assess the clinical utility of these techniques in SOT recipients.
Summary:
CMV, BK, EBV major cause of morbidity and mortality in immunocompromised individuals.
Risk of recurrent infection: CMV seropositive allogeneic HSCT patients, R-/D+ SOT, HIV, patients who have received T-cell depletion therapies.
The incidence of CMV reactivation/reinfection in SOT is 16–56%, with a median value of 30%
CMV-specific T-cell adoptive transfer used for CMV infection and disease in ulcerative enteritis in primary immunodeficiency or in paediatric retinitis caused by CMV
CMV-specific CTLs from third donors used in KTRs (D+/R-) with refractory CMV infection showed good results with resolution of TMA features, suggesting that creating donor cell-banks could be useful as a therapeutic alternative in SOT recipients.
Avaiable Cellular therapies
A) T-Cell Expansion: Epitopes like pp65, IE-1 used by APC to activate and proliferate CMV-peptide-specific T-cells. Negative aspect is the use of a single viral epitope therefore its application may be limited for HLA-A2 patients/donors, and risk of producing infection later.
B) Direct Selection Using Specific Peptide–MHC: Using pMHC multimers allows isolating T-cells based on TCR ability to bind a complex mixture of peptide-loaded recombinant HLA molecules. It only isolates only CD8, or CD4 T-cells; irreversible cell binding may alter the function of the T-cells.
C) Direct Selection Using Cytokine Capture System: rapid assay that allows to select and enrich CD8+ and CD4+ INF-gamma secreting T-cells that have been previously stimulated using viral antigens. No HLA restrictions
D) T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR):
The gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR).
Cell Therapy Limitations and Alternatives in SOT Patients:
Deficiencies in T-cell differentiation and lifelong immunosuppression can affect to long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipients., can be overcome by:
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation:
Treatment and prevention of CMV, BKV, PTLD, rejection
Summary
· T cell mediated immune response plays important role to prevent viral replication in transplant recipients.
· Use and infusion of CMV specific T cells can be beneficial in treatment of refractory cases.
· In addition, it will be better option of treatment to avoid risk of nephrotoxicity and anti viral resistance associated with the use of antivirals as ganciclovir, foscarnet and cidofovir.
· May steps are essential to get CMV specific T lymphocytes:
§ Ex vivo expansion of T cells by using APC carrying viral antigens.
§ Direct selection of T cells using cytokine capture system.
§ Genetic engineering to transfer high CMV affinity cells.
Other uses of it in the field of transplantation:
· In EBV related PTLD (when resistant to reduction of IS and classic chemotherapy, CHOP protocol).
· Refractory cases of BKN, not responding to reduction of immunosuppression.
Management of graft versus host diseas
Introduction
▪︎CMV infection in transplant recipients is one of the main infectious complications. The incidence of CMV reactivation/ reinfection in SOT is 16–56%.
▪︎It can cause direct effects and indirect effects related with increased incidence of graft rejection and opportunistic infections or decreased recipient survival.
▪︎Cell mediated immune response is considered the most important arm of the immune system against CMV infection
with increasing evidences demonstrating a role of CMV-specificT-cells in protecting from infection.
▪︎There are still some issues associated with the use of the available antivirals (ganciclovir, foscarnet, cidofovir and more recently letermovir) such as undesirable side effects (nephrotoxicity) and selection of resistance mutations in addition to the high cost. Consequently,strong efforts have been made to search for new therapeutic
approaches.
In this context, the use of cellular therapy may be useful to reconstitute the CMV specific T-cell response and to control
CMV viremia in SOT recipients.
▪︎This study provided a synthesis of recent data regarding the impact of using CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients, the different approaches to stimulate, isolate and expand CMV-specific T-cells developed over the years & a discussion of the possible use of CMV adoptive cellular therapy in these patients.
☆ The use of adoptive transfer of CMV specific T-cells in the context of solid organ transplantation
▪︎ CMV-specific T-cell transfer has been widely investigated and applied to Hematopoietic Stem Cell Transplant (HSCT) patients as prophylaxis and treatment.
▪︎In SOT recipients it has been less investigated probably due to the T-cell response attenuation and recipients may not tolerate donor derived cytolytic T lymphocytes (CTLs).
▪︎Few authors have explored the use of T-cell adoptive transfer in SOT recipients during the last decade
▪︎A number of authors have explored the potential of T-cell adoptive transfer as a therapy in SOT recipients.
▪︎A study highlighted the effective application of CMV-specific CTLs from third donors.
▪︎Some studies indicated that adoptive therapy can contribute to immune control of CMV infection.
▪︎Some trial suggested that; the use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment.
☆ CONCLUSION
▪︎The use of T-cell adoptive therapy may help to restore the CMV-specific immunity for preventing CMV infection in addition to serve as a treatment for CMV infections in SOT individuals who do not respond to conventional therapies, such as patients infected with antiviral resistant strains with no alternative treatment available.
Dear All
Thank you for understanding the basis of adoptive immunotherapy in the context of refractory CMV infection/disease. As you can see the crucial role of cell mediated immunity in clearing CMV infection. What about antibody mediated component in fighting CMV infection given the fact that seronegative recipients are at high risk of infection from seropositive donors?
Dear Dr Mohsen,
The role of humoral immunity can be simulated by using CMV IVIG (cytomegalovirus immune globulin) which may have a role in the management of drug-resistant CMV infection. However, a well-designed RCT to evaluate the efficacy of this approach is still awaited (1).
References:
1) Santos CAQ, Vella J, Brennan DC. Clinical manifestations, diagnosis, and management of cytomegalovirus disease in kidney transplant recipients. ©2023 UpToDate® (accessed on 3 March 2023).
SUMMARY
Introduction
· Viral infections like CMV, EBV and BK virus cause significant morbidity and mortality in immunocompromised patients.
· The incidence of CMV reactivation/reinfection in SOT is 16–56% , while in HSCT has been reported to be 30–70%.
· CMV seropositive HSCT, and CMV D+/R- predict a high risk of recurrence of infection
· Cell mediated immune response is the most significant arm to prevent CMV disease.
· The role of CMV specific T-cells in term of protection from infection is paramount.
· Anti virals against CMV having undesirable side effects including nephrotoxicity.
· So, the use of cellular therapy may be helpful to reconstitute the CMV specific T-cell response and to control CMV viremia in SOT recipients.
Use of adoptive transfer of CMV-specific T cell in the context of SOT
· The use of CMV-specific T-cell adoptive transfer is currently being evaluated for clinical application, with promising results as a treatment for CMV infection and disease
· The period early after the transplant is considered critical due to the high risk of infections associated with a high incidence of CMV.
· The CMV-specific T-cell transfer has been well researched and applied to HSCT patients, prophylactically, to reconstitute protective antiviral immunity, and as a treatment in patients with refractory CMV infection
· The role of CMV-specific T-cell immune reconstitution after SOT have demonstrated several benefits, including lower risk of CMV infection.
Methods of generating CMV specific T cell:
· T-cell expansion
· Direct selection using specific peptide – MHC
· Direct selection using cytokine capture
· T cell generation using activation marker and engineered T-cells
Cell therapy limitation and alternative in SOT patient
Conclusion
The use of T-cell adoptive therapy may help in SOT individuals who do not respond to conventional therapies, such as patients infected with antiviral resistant strains.
The role of Adoptive immunotherapy in managing different conditions related to transplantation
Thank you for summary. You referred to the use of adoptive immunotherapy in the treatment of resistant EBV PTLD. Are you aware of antivirals specific to EBV to produce any resistant strains?
Is It Feasible to Use CMV-Specific T-Cell Adoptive Transfer as
Treatment Against Infection in SOT Recipients?
Transplanted patients lacking CMV-specific T-cell immunity have an increased occurrence of CMV replication episodes and CMV-related complications.
Introduction.
Viral infection, including cytomegalovirus (CMV), BK virus and Epstein-Barr virus are considered common viral infection in immunocompromised group, CMV seropositive allogeneic HSCT patients presents the highest risk of recurrent infections, followed by CMV seronegative SOT recipients that receive a graft from a seropositive donor (R-/D+), HIV patients, and patients who have received T-cell depletion therapies (Alemtuzumab, antithymocyte globulin, or post-transplant cyclophosphamide).
Direct effects of CMV proliferation causing viral syndrome with clinical manifestations such as (gastroenteritis, pneumonitis, hepatitis, uveitis, retinitis, encephalitis and graft rejection).
CMV infection also cause indirect effects related with increased incidence of graft rejection and opportunistic infections or decreased recipient survival, the use of the available antivirals (ganciclovir, foscarnet, cidofovir and more recently letermovir) is effective but have undesirable side effects (nephrotoxicity) now the role of cellular therapy such as CMV-specific T-cell adoptive has effect on CMV viremia.
USE OF ADOPTIVE TRANSFER OF CMVSPECIFIC T-CELLS IN THE CONTEXT OF SOLID ORGAN TRANSPLANTATION.
Using in severe and persistent CMV pneumonia resistant to ganciclovir and Foscarnet and shown decreasing in viral load and improving of clinical manifestation and these results suggest that, although there is still space for improvement, the use of CMV-specific T-cell adoptive
transfer is promising in SOT recipients with limited options for CMV-infection treatment.
CELLULAR THERAPIES AVAILABLE.
T-Cell Expansion.
IE-1 and pp65 proteins are two of the most immunodominant CMV antigens and have been widely used to stimulate the CMV-specific immune response. T-cell ex vivo stimulation and expansion requires a small blood volume to establish the T-cell culture, making possible the generation of CMV-specific T-cells from low levels of circulating T-cells and naive donor sources.
Direct Selection Using Specific Peptide–MHC (pMHC).
This method allows to reduce the time and improve the quality of the final product, minimizing alloreactivity.
Direct Selection Using Cytokine Capture System (CCS).
CMV-specific T-cells can also be selected using IFN-g cytokine capture system (CCS), a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral antigens.
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR).
By modifications of the TCR using genetic engineering technology has been able to enhance the specificity and affinity of the recognition of the antigens by T-cells.
Cell Therapy Limitations and Alternatives in SOT Patients.
1-lifelong immunosuppression can affect to long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipients.
2-Deficiencies of T-cell differentiation in SOT recipients receiving immunosuppression.
3-Infusion of donor derive T-cells from donors may also transfer alloreactive T cells in numbers sufficient that could trigger episodes of rejection.
4-Selection of T-cells on the basis of HLA allele phenotype, viral specificity and HLA restriction by using third party cell banks.
CONCLUSIONS
The protective role of CMV-specific T-cell immune response
against CMV infection and disease is now clear enough with good and promising result, and thus the use of T-cell adoptive therapy may help to restore the CMV-specific specially with disseminated and anti-viral resistance infection.
What about the role of adoptive immunotherapy in other aspects of SOT?
IS IT FEASIBLE TO USE CMV SPECIFIC T CELL ADOPTIVE TRANSFER AS TX AGAINST INFECTION IN SOT RECIPIENTS?
Introduction.
-CMV,BK & EBV are major causes of morbidity and mortality in immunosuppressed.
-Incidence of CMV reactivation or reinfection is 30-70%;median 37%.
-Antiviral meds have been the mainstay of treatment for CMV but with increased SE, cellular therapy is being explored to assess whether we can better our outcomes post transplant.
Use of adoptive transfer of CMV specific T cells in context of SOT.
-CMV specific T cells used in HSCT > SOT.
-Cytotoxic T cells are harvested from pts peripheral blood mononuclear cells, stimulated, set aside and infused in patients. Infused cells can last up to 24 months. T cells preparation (expansion + stimulation) can be ex vivo or in vivo with the former needing less blood to get a T Cell culture.
-A number of studies on these are ongoing before level of safety and efficacy can be established.
Cellular therapies available.
1.T cell expansion
-IE & PP65 proteins are CMV ag used to stimulate CMV immune response.
-In vivo expansion and generation of CMV specific T cells involves;
-Ex vivo expansion needs a small qty of blood for T cell culture thus making generation of CMV T cells possible from low circulating levels of T cells.
2.Direct selection using specific peptide MHC(pMHC)
-T cells are isolated based on T cell receptor ability to get attached to a mixture of peptide loaded recombinant HLA molecule.
3.Direct selection using cytokine capture system(CCS)
-CMV specific T cell isolated by interferon gamma CCS facilitating T cell selection that unlike pMHC lacks HLA restriction.
4.T cell generation using activated marker and engineered T cells.(CAR,TCR)
-CAR entails a specific Ag binding domain represented by a single chain fragment variable Ab, extracellular spacer, transmembrane and an intracellular region that activates T cells.
-TCR uses heterodimers integrated by alpha and beta peptide chains to identify specific peptides presented by MHC complexes.
Cell therapy limitations and alternatives in SOT pts.
-Duration and intensity of immunosuppression leads to viral infection in SOT.
-Antivirals have SE; Nephrotoxicity and drug resistant CMV strain.
-Deficiencies of T cell differentiation in SOT recipients getting immunosuppression.
-Solution to some of the aforementioned is RIS during the post infusion phase to allow for expansion and functionality of CMV specific T cell.
FUTURE DIRECTIONS AND PERSPECTIVE.
-CMV specific T cell immune reconstitution post SOT have advantages ;Less risk of CMV infection and graft rejection.
-3rd party CMV specific T cells can be used to overcome challenges with enrolling SOT in clinical trials; Difficulty of T cell expansion in SOT recipients on immunosuppressive therapy, increased risk of graft rejection and T cell administration.
ROLE OF ADOPTIVE IMMUNOTHERAPY IN OTHER CONDITIONS RELATED TO TRANSPLANT.
Can be used in;
I’m assuming you mean management of GVHD (Mgt GVHD). Can you please quote a reference to this statement?
GVHD is one of the complications post transplant, Adoptive immunotherapy has been tried in a few studies to try institute long term peripheral tolerance and decrease GVHD incidence while preserving anti leukemic immunity. In another study GVHD incidence was postulated to decrease by modifying adoptive immunotherapy by decreasing the CD8 +VE T cells from lymphocyte concentrate or transfusing very low number of cells and increasing the dose in a systematic manner.
REFERENCES;
1.Alice et al-Graft engineering and adoptive immunotherapy; New approaches to promote immune tolerance after hematopoietic stem cell transplantation. Front Immunology .vol 10-2019
2.Kolb et al – Adoptive immunotherapy with donor lymphocyte transfusion. Current opinion in oncology9(2);p 139-145,March1997
3.Lingling Zhang et al- Advances in targeted immunotherapy for graft versus host disease; Front immunol.2018;9;1087
4.Lukas M Braun et al ; Immunomodulatory therapies for treatment of graft versus host disease. Hemasphere 2021 njun;5(6);e581
# Introduction:
*Viral infection, including (CMV), (BKV) and (EBV), still considered as a main cause of morbidity and mortality in immunocompromised individuals.
*In (HSCT) and (SOT) recipients, CMV infection is one of the main infectious complications.
*The incidence of CMV reactivation/reinfection in SOT is 30%.
*It cause proliferation that lead to viral syndrome with clinical manifestations such as (gastroenteritis, pneumonitis, hepatitis, uveitis, retinitis and encephalitis), with increased incidence of graft rejection and opportunistic infections or decreased recipient survival.
*Cell mediated immune response is considered the most important arm of the immune system against CMV infection.
*Using both immunological and virological monitoring may facilitate clinical decisions during follow-up of SOT recipients *The use of cellular therapy may be useful to reconstitute the CMV specific T-cell response and to control CMV viremia in SOT recipients and mainly using CMV-specific T-cell adoptive transfer on the control of CMV infection.
# Use of adoptive transfer of CMV specific T- cell in the context of SOT:
*The use of CMV-specific T-cell adoptive transfer is widely investigated and applied to (HSCT) patients, but in SOT recipients it has been less investigated probably due to the T-cell response attenuation produced by the administration of the immunosuppressive therapy.
* SOT recipients may not tolerate donor derived (CTLs) due to the activation of cytokine-mediated stimulation of the alloreactive T-cells causing direct alloimmune injury.
*Many studies results indicated that adoptive therapy can contribute to immune control of CMV infection.
#T-Cell Expansion
*To successfully generate and expand CMV-specific T-cells, it is crucial to define the most immunogenic epitopes used by (APC) to promote the activation and proliferation of peptide-specific T-cells.
*IE-1 and pp65 proteins are two of the most
immunodominant CMV antigens and have been widely used to
stimulate the CMV-specific immune response.
# Direct Selection Using Specific Peptide–MHC (pMHC)
Using pMHC multimers allows to isolate T-cells based on the Tcells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules.
# Direct Selection Using Cytokine Capture System (CCS):
Using IFN-g cytokine capture system (CCS), a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral antigens.
# T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
It is the gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR) and can be designed to specifically target conserved and essential epitopes of the selected antigen .
# Cell Therapy Limitations and Alternatives in SOT Patients
*The intensity and long-term IS requirement to prevent allograft rejection lead to a wide range of viral complications.
Antiviral treatment can generate side effects such as nephrotoxicity.
Selection of drug-resistant mutantCMVstrains limiting treatment capability in SOT recipients.
What about other roles of adoptive immunotherapy in SOT?
IV. Is It Feasible to Use CMV-Specific T-Cell Adoptive Transfer as Treatment Against Infection in SOT Recipients?
Summarise this article.
Introduction
Viral infections (e.g., CMV, EBV, BKV) are a major cause of morbidity and mortality in immunosuppressed patients. CMV infection increases the risk of graft rejection and also contributes to poor graft and patient survival.
The cell-mediated immune response plays a significant role against CMV infection. Transplant recipients lacking CMV-specific T-cell immunity are at an increased risk of CMV replication and CMV-related complications. Therefore, cellular therapy may be necessary to reconstitute the CMV-specific T-cell immune response.
Use of adoptive transfer of CMV-specific T-cells in the context of SOT
In hematopoietic stem cell transplant (HSCT), use of adoptive transfer of CMV-specific T-cells has been widely studied and applied. It has been used to reconstitute the protective antiviral immunity and as a treatment option in patients with refractory CMV infection.
Cells are obtained from the patient’s peripheral blood mononuclear cells (PBMC) then they are stimulated, isolated, expanded and infused back into the patient. This treatment option is associated with immunological reconstitution and control of the viremia.
Infused cells can last up to 2 years. T-cell stimulation and expansion can be done in vivo or ex vivo, the latter requires a small blood volume to establish the T-cell culture.
There is a clinical trial assessing the biological efficacy of therapeutically administered donor-derived specific cytotoxic T lymphocytes (CTLs) targeting CMV following SOT or allogeneic blood or marrow stem cell transplant.
Cellular therapies available: –
These are the methodologies used to generate CMV-specific T-cells.
In order to generate and expand CMV-specific T-cells, it is important to identify the most immunogenic epitopes used by the APCs to promote the activation and proliferation of peptide-specific T-cells
Use of pMHC multimers allows isolation of T-cells based on the T-cells receptor ability to bind a mixture of peptide-loaded recombinant HLA molecules.
Advantage – reduces time spent and improves the quality of the final product hence minimizing alloreactivity
Disadvantage – can only isolate CD8+ OR CD4+ T-cells
Partially HLA-matched CMV-specific T-cells obtained from a third-party donor can be used to minimize the challenges associated with this therapy.
CCS is a rapid assay used to select and enrich CD8+ and CD4+ T-cells that had been previously stimulated using viral antigens.
Unlike pMHC it has no HLA restriction.
Cells can also be isolated based on the detection of specific surface molecules which are selectively expressed or strongly up-regulated following T-cell activation e.g., CD25, CD69, CD137 and CD154.
Involves gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR). Further clinical studies are needed to demonstrate in vivo efficacy.
CAR-T-cell therapy recognizes antigens exclusively located on the cell surface while TCR can also identify intracellular antigenic fragments presented by MHC molecules.
Disadvantage – TCR T-cell therapy is restricted to MHC presentation
The main aim of TCR T-cells is to modify the TCR binding to pathogenic antigens.
The affinity of TCRs for pathogenic antigens is naturally low hence, genetic engineering technology is used to modify and overcome this problem.
Duration and intensity of immunosuppression predisposes SOT recipients to viral infections.
Antiviral treatment is associated drug toxicities e.g., nephrotoxicity as well as development of drug-resistant CMV strains.
In view of these limitations, cell therapy serves as an appropriate and effective alternative to antiviral treatment.
Limitations of cell therapy include deficiencies in T-cell differentiation and chronic immunosuppression which can affect the long-term survival of the transfused cells. These limit its use in SOT recipients.
The solution to these limitations includes decreasing the immunosuppression dose during the post-infusion period. This allows the expansion and functionality of the CMV-specific T-cells.
Third-party CMV-specific T-cells can also be used.
Future directions and perspectives
In SOT recipients, CMV is associated with severe complications like graft loss.
CMV-specific T-cell immune reconstitution following SOT reduces the risk of CMV infection and graft rejection.
Enrolling SOT recipients into clinical trials is difficult due to challenges of T-cell expansion in SOT recipients on immunosuppressive therapy as well as the increased risk of graft rejection after T-cell administration. To overcome this challenge, third-party CMV-specific T-cells can be used.
Conclusions
There is a defined protective role of CMV-specific T-cell immune response against CMV infection and disease.
Use of the T-cell adoptive immunotherapy helps restore the CMV-specific immunity for prevention of CMV infection as well as for treatment of CMV infection and CMV disease in SOT recipients who fail to respond to the conventional therapies e.g., patients with a drug-resistant CMV strain.
More clinical trials are needed to fully elucidate and assess the clinical utility of these techniques in the SOT recipient population.
Address the role of adoptive immunotherapy in managing different conditions related to transplantation.
In adoptive immunotherapy, T-cells are stimulated, isolated, expanded and infused back into the patient to treat/ control a certain condition.
– Management of BKV nephropathy (1, 2)
– Management of CMV disease (2)
– Management of EBV-related lymphomas (3)
– To prevent rejection in living donor kidney transplant recipients (TRACT Trial) (4)
– Management of GVHD (graft versus host disease) (5)
References
1. Jahan S, Scuderi C, Francis L, Neller MA, Rehan S, Crooks P, et al. T-cell adoptive immunotherapy for BK nephropathy in renal transplantation. Transplant infectious disease : an official journal of the Transplantation Society. 2020 Dec;22(6):e13399. PubMed PMID: 32608543. Pubmed Central PMCID: PMC7816252. Epub 2020/07/02. eng.
2. Parajuli S, Jorgenson M, Meyers RO, Djamali A, Galipeau J. Role of Virus-Specific T Cell Therapy for Cytomegalovirus and BK Infections in Kidney Transplant Recipients. Kidney360. 2021 May 27;2(5):905-15. PubMed PMID: 35373059. Pubmed Central PMCID: PMC8791350. Epub 2022/04/05. eng.
3. Heslop HE, Sharma S, Rooney CM. Adoptive T-Cell Therapy for Epstein-Barr Virus-Related Lymphomas. Journal of clinical oncology : official journal of the American Society of Clinical Oncology. 2021 Feb 10;39(5):514-24. PubMed PMID: 33434061. Pubmed Central PMCID: PMC8462582. Epub 2021/01/13. eng.
4. Mathew JM, J HV, LeFever A, Konieczna I, Stratton C, He J, et al. A Phase I Clinical Trial with Ex Vivo Expanded Recipient Regulatory T cells in Living Donor Kidney Transplants. Scientific reports. 2018 May 9;8(1):7428. PubMed PMID: 29743501. Pubmed Central PMCID: PMC5943280. Epub 2018/05/11. eng.
5. Trzonkowski P, Bieniaszewska M, Juścińska J, Dobyszuk A, Krzystyniak A, Marek N, et al. First-in-man clinical results of the treatment of patients with graft versus host disease with human ex vivo expanded CD4+CD25+CD127- T regulatory cells. Clinical immunology (Orlando, Fla). 2009 Oct;133(1):22-6. PubMed PMID: 19559653. Epub 2009/06/30. eng.
Is It Feasible to Use CMV-Specific T-Cell Adoptive Transfer as Treatment Against Infection in SOT Recipients?
Estefani Garcia-Rios et al. in this review article examined the utility of cellular therapy in the reconstitution of the CMV specific T-cell response and controlling CMV viremia in recipients of solid organ transplants. This article elucidates on a review of recent data concerning the impact of using CMV-specific T-cell adoptive transfer on the control of CMV infection in recipients of solid organ transplants, the various approaches to stimulate, isolate and expand CMV-specific T-cells developed over time and a highlight of the potential utility of CMV adoptive cellular therapy in these patients.
Use of Adoptive Transfer of CMV-Specific T-Cells in the Context of Solid Organ Transplantation
A promising outcome of treatment using adoptive CMV-specific T-cell transfer has been observed in treatment of CMV infection and disease, ulcerative enteritis in primary immunodeficiency and in pediatric retinitis caused by CMV.
In transplantation medicine, CMV-specific T-cell transfer has been studied extensively and found useful in Hematopoietic Stem Cell Transplant (HSCT) recipients, both for prophylaxis and reconstitution of antiviral immunity, and as a treatment option in refractory CMV infection.
However, in SOT recipients investigated has been limited probably due to the poor T-cell response caused by the administration of the immunosuppressive therapy. Additionally, SOT recipients may reject donor-derived cytolytic T lymphocytes (CTLs) due to the activation of cytokine-mediated stimulation of the alloreactive T-cells.
Brestrich et al. in a study of lung transplanted recipient with severe and drug resistant CMV pneumonia infused CMV- specific T cells 4 weeks apart. There was an improvement after the first infusion but the patient died due to graft failure with a negative biopsy for CMV antigen. Thereafter many other studies have been done in the past decade to build on this and have shown favorable response. The most notable of these studies was done in 21 SOT recipients who had recurrent ganciclovir resistant CMV infections. Thirteen of the study participants were subjected to T-cell adoptive transfer receiving a maximum of 6 doses. Adverse events noted were fatigue and malaise but with no change in the graft status. Eleven of the 13 showed objective improvement in their symptoms and viral load.
Cellular Therapies Available
T-Cell Expansion – IE-1 and pp65 proteins are two of the most immunogenic CMV antigens used by APCs to stimulate T cell activation and proliferation and have been widely used to stimulate the CMV-specific immune response. In the earlier studies, CMV-specific CD8+ T-cell clones were produced by stimulating donor mononuclear cells obtained from peripheral blood (PBMC) with CMV-infected fibroblasts. Unfortunately, this resulted in recipient infection and had to be discontinued. Subsequently, CMV-specific T cell production was achieved through stimulation by lysates or pp65-NLV peptide. But the resultant T cell generated had limited usage as it was specific for only a viral epitope, thus limiting the utility. However, by using “poly-specific” products targeting multiple antigens this problem was resolved and T cells were generated by incubating allogeneic T-cells in vitro with clusters of 15-mer peptides spanning the entire pp65 antigen to generate CMV-specific oligoclonal T-cells. Adoptive transfer of this oligoclonal T-cells led to elimination of viremia with a lasting presence of over 2 years in circulation. Improvements in the technique over time have reduce alloimmune response activation.
Direct Selection Using Specific Peptide–MHC (pMHC) – Use of specific peptide MHC to bind the T cell receptor and stimulate T cell production by applying the knowledge of immunogenicity of IE-1 and pp65. This method is limited by its ability to produce only CD4+ and CD8+ T cell population. Also, the irreversibilty of the binding to the T cell receptor can cause pMHC multimers allows to isolate T-cells based on the T-cells receptor (TCR) can cause functional alteration such as internalization, activation, overstimulation and death. The Streptamer technology has been used to solve this problem. It is able to reverse the peptide-T – cell receptor binding. The peptide competes with the Streptamer and causes its monomerization and preventing functional alteration of the T- cell receptor.
Direct Selection Using Cytokine Capture System (CCS) – Use of IFN-γ cytokine capture system (CCS) to select CMV-specific T-cells. Viral antigens are used to stimulate CD4+ and CD8+ INF-γ secreting T-cells that not restricted to a specific HLA. Based on expression of certain molecules such as CD25, CD69, CD137 and CD154 which are seen after T cell activation, virus specific T cells can be isolated and enriched for production and use.
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
This successful therapy in cancer treatment entails the genetic modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR) leading to the generation of autologous CAR T-cells. It has now been explored as immunotherapy against CMV by enabling antigen recognition in a MHC independent manner. This can be tailored to specifically target conserved and essential epitopes of the selected antigen, overcoming pathogen escape mechanisms.
Cell Therapy Limitations and Alternatives in SOT Patients
Long term survival of transfused T cells is affected by the prolonged immunosuppression that affects T cell differentiation and its antiviral properties. Additionally, in vitro generated T cells are sensitive to immunosuppressive medications which further impairs their ability to produce cytokines for proliferation. Genetically modified T cells that will be resistant to these drugs is a possible solution to this problem. Alternatively, reducing patient´s immunosuppression after T cell infusion may allow the expansion and functionality of the CMV-specific T-cells. Moreover, T cell infusion can trigger alloimmune activation and graft rejection, this can be curtailed by culturing T cell clones that will eradicate alloreactive T cells.
Future Directions and PerspectivesAdoptive T cell transfer could be the cornerstone of treatment of drug resistant CMV infection but there are several limitations to isolating and using these cells. To solve this problem, the use of third-party CMV-specific T-cell banks to ensure the availability of well characterized the T-cell products is necessary. Additionally, we need better results on studies using T-cell adoptive immunotherapy in SOT recipients that had optimal clinical outcomes.
Is It Feasible to Use CMV-Specific T-Cell Adoptive Transfer as Treatment Against Infection in SOT Recipients?
Summary of this article:
Viral infection, including cytomegalovirus (CMV), BK virus, and Epstein-Barr virus,
remains a significant cause of morbidity and mortality in immunocompromised
individuals. While in immunocompetent individuals, latent CMV infection is controlled by
the immune system.
The incidence of CMV reactivation/reinfection in SOT is 16–56%
A cell-mediated immune response is considered the most critical arm of the immune
system against CMV infection.
CMV infection after transplantation is common; around one third of patients receiving
organ may develop CMV infection
CMV infection can affect the outcome of SOT through various mechanisms:
CMV may infect the graft and cause graft dysfunction Reduction of immunosuppression
may predispose to rejection The use of antiviral is associated with side effects
The principle of adoptive immunotherapy in treatment of CMV infection after
transplantation is using CMV specific cytotoxic T lymphocytes (ex vivo T-cell culture) or
donor lymphocyte infusion to kill CMV infected cells.
The transfer of CMV-specific T-cell is widely used in Hematopoietic Stem Cell Transplant
(HSCT) patients; on the other hand it is less studied in the settings of organ
transplantation which may be explained by the rule of immunosuppression which may
attenuate T cell response, moreover, infusion of donor lymphocytes may cause immune
response and graft versus host disease
Side effects of adoptive immunotherapy:
-Graft Versus Host Disease (GVHD) which is less common if using CMV specific cytotoxic T lymphocytes, and very common when using donor derived lymphocytes
-Allergic reactions
-Flue like symptoms
Cellular therapy available for generation of CMV specific T-cells:
– T-cell expansion
– Direct selection using specific peptide – MHC (pMHC)
– Direct selection using cytokine capture (CCS)
– T-Cell Generation Using Activation Markerand Engineered T-Cells (CAR, TCR)
Cell Therapy Limitations and alternatives in SOT Patients:
The main limitation for the use of cellular therapy is the use of long term
immunosuppression that can affect the long term survival of transfused T cells, this can
be managed by reduction of immunosuppression once the cells are transfused and to
genetically modify the in vitro generated cytotoxic T cell to allow for resistance to the
immunosuppressive drugs.
The role of Adoptive immunotherapy in managing different conditions related to transplantation:
– Treatment of resistant and refractory cases of EBV+ PTLD cases
– May be used for the treatment of acute rejection through infusing Treg cells
– Treatment of resistant cases of CMV, BKN.
Conclusion:
-The use of T-cell adoptive therapy may help to restore the CMV-specific immunity for
preventing CMV infection in SOT individuals who do not respond to conventional
therapies, such as patients infected with antiviral resistant strains
-Recent studies have significantly increased our knowledge about the protective role of
CMV-specific T-cell immune response against CMV infection and disease
– Further work is clearly needed in order to fully understand and assess the clinical utility
of these techniques in SOT recipients.
Is-It-Feasible-to-Use-CMV-Specific-T-Cell-Adoptive-Transfer-as-Treatment-Against-Infection-in-SOT-Recipients?
INTRODUCTION:
Viral infections especially cytomegalovirus (CMV), BK virus and Epstein-Barr virus, are commonest complications of organ transplant and HSCT and lead to increase risk of morbidity and mortality.
CMV infection post transplant carry high risk of recurrent infections especially in seronegative recipients received a graft from a seropositive donor (R-/D+), HIV patients, and patients who have received T-cell depletion therapies (alemtuzumab, antithymocyte globulin, or post-transplant cyclophosphamide.
The incidence of CMV reactivation/reinfection in SOT is 16–56%.
Clinical manifestations of CMV infection can cause gastroenteritis, pneumonitis, hepatitis, uveitis, retinitis, encephalitis and graft rejection mainly due to direct effects of CMV proliferation.
This study focus on the role of CMV-specific T-cells in protecting from infection, which may improve clinical care after transplantation.
USE OF ADOPTIVE TRANSFER OF CMV- SPECIFIC T-CELLS IN THE CONTEXT OF SOLID ORGAN TRANSPLANTATION:
CMV-specific T-cell adoptive transfer is promising to use in treatment of CMV infection and disease in ulcerative enteritis in primary immunodeficiency or in pediatric retinitis caused by CMV.
CMV-specific T-cell transfer used in cases of Hematopoietic Stem Cell Transplant (HSCT) patients as a protective antiviral immunity, and as a treatment in patients with refractory CMV infection.
However there is still limited data on using for treatment CMV in organ transplant.
But there’s studies on case with persistent CMV viremia resist to ganciclovir and pneumonia post lung transplant, where treated with two infusions of 1 × 107/m2 CMV‐specific T-cells and shows improvement of clinical situations and decrease CMV viremia with increase of the CMV- specific T-cell levels. Unfortunately patients died because of graft failure.
Since use T-cell adoptive transfer as a therapy in SOT recipients in refractory CMV lead to fifty fold decreased of the CMV DNA viral load.
Also used in treatment of Thrombotic thrombocytopenia purpura with successful outcome .
transferring allogeneic CMV-specific T lymphocytes on CMV infection or reactivation. This therapy promised to treat CMV infection and CMV disease in organ transplant. but it’s side effects is fatigue and malaise. It’s very effective in reduce CMV viremia and disease and increase T cell.
In many studies shows improvement in clinical syndrome of CMV infection and absence of CMV antigen and always death in organ transplant with CMV infection dia from other complications rather than CMV infection.
CELLULAR THERAPIES:
T-Cell Expansion:
This method used to generate T cell expansion
There are different approaches used for T cell in vivo expansion.
First approach// T cell expansion is generated by stimulating donor peripheral blood mononuclear cells (PBMC) with CMV-infected fibroblasts. but this approach may induce infection in patients. So this approach no more use.
Other approach is CMV lysates or pp65-NLV peptide were used to stimulate CMV-specific T-cells.
The main action is to stimulate adoptive immunity against a single viral epitope.
It’s action to eliminate viremia.
Direct Selection Using Specific Peptide–MHC (pMHC):
It’s for HLA typing only. This method used to isolate only CD8+ or CD4 T-cell.
This method allows to reduce the time and improve the quality of the final product, less alloreactivity. it’s designed for alteration of T cell function. Due to use of immunosuppressive drug leading deficiencies in T-cell differentiation and affects longterm survival of the transplanted cells limiting its use for adoptive therapy. but still use in treat CMV infection. It’s still under search.
Direct Selection Using Cytokine Capture System (CCS):
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR):
Cell Therapy Limitations and Alternatives in SOT Patients:
Due to use of immunosuppressive therapy which reduce T cell proliferation and function and also long term use of CMV eradication therapy which are nephrotoxic and development of drug resistance to CMV virus; all of these factors predispose patients to develop CMV viremia and disease, So cell therapy may be an appropriate and effective alternative antiviral treatment.
Also due to T cell depletion with use of immunosuppressive drug ; so should be reduce dose of immunosuppressive drug to allow the expansion and functionality of the CMV-specific T-cells.
third-party T-cells to infuse a kidney transplant patient who had ganciclovir resistant persistent CMV viremia, and decreased the levels of immunosuppressive drugs. This shows significant decrease of CMV DNA viral load within 4 months post infusion and continuous controlled up-to 1 year.
use of T-cell adoptive therapy may help to restore the CMV- specific T cell.
In treatment of PTLD post EBV/ BK virus
In treatment of GVHT
In Case of antiviral resistance
I note that adoptive transfer of immunity holds a lot of promise in a range of disorders in transplant recipients
Please summarise this article
INTRODUCTION
· In immunocompromised people, viral infections such as (CMV), BK virus, and Epstein-Barr virus continue to be a major source of morbidity and mortality.
· CMV infection is one of the main infectious problems in transplant recipients, both for hematopoietic stem cell (HSCT) and solid organ transplantation (SOT).
· In addition to the clinical signs of the viral syndrome caused by CMV proliferation, which has direct effects, CMV infection can also result in a higher incidence of graft rejection, opportunistic infections, or a lower recipient survival rate.
· As more evidence suggests that CMV-specific T-cells play a role in infection protection, the immune system’s cell-mediated response is seen as the most crucial defense against CMV infection.
· Strong attempts have been undertaken to look for alternative therapeutic options due to problems with the new anti-CMV medications such as toxicity, cost, and resistance.
USE OF ADOPTIVE TRANSFER OF CMV- SPECIFIC T-CELLS IN THE CONTEXT OF SOLID ORGAN TRANSPLANTATION
· Contrary to its widespread investigation and use in hematopoietic stem cell transplant recipients and its use as a treatment for CMV infection in current applications like ulcerative enteritis in primary immunodeficiency or in pediatric retinitis caused by CMV, it has received less research in SOT recipients. This is likely because the immunosuppressive therapy’s administration attenuates the T-cell response.
· In addition, donor-derived cytolytic T lymphocytes (CTLs) may not be tolerated by SOT recipients because they directly stimulate alloreactive T-cells, causing alloimmune damage.
CELLULAR THERAPIES AVAILABLE
T-Cell Expansion
· T-cells that are specific to CMV were stimulated with CMV lysates or the pp65-NLV peptide. Adoptive immunity was solely activated by the pp65-NLV peptide against a specific viral epitope.
· The oligoclonal T-cell adoption was successful in eliminating viremia, and the infused cells survived for up to two years.
Direct Selection Using Specific Peptide–MHC (pMHC)
· The capacity of the T-cell receptor (TCR) to bind a complex combination of peptide-loaded recombinant HLA molecules enables the isolation of T-cells using pMHC multimers.
· This technique minimizes alloreactivity while cutting down on time and improving the quality of the end result.
· The method’s restriction to isolating just CD8+ or CD4 T-cell populations, as well as the binding’s irreversibility, which might result in alterations to the T-cell phenotypic, are its principal drawbacks.
Direct Selection Using Cytokine Capture System (CCS)
· A rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral.
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
· Adding tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors to a patient’s lymphocytes is another intriguing strategy based on the effectiveness of cancer treatment (CAR).
CONCLUSIONS
· Our understanding of the protective function of the CMV-specific T-cell immune response against CMV infection and illness has considerably increased as a result of studies conducted.
· T-cell adoptive therapy may be used as a treatment for CMV infections in SOT individuals who do not respond to conventional therapies, such as patients infected with antiviral-resistant strains that have no other available options, in addition to helping to restore the CMV-specific immunity for preventing CMV infection.
· The use of CMV-specific adoptive transfer as an alternate therapy for SOT recipients may be aided by recent findings. However, to evaluate the therapeutic effectiveness of these approaches in SOT recipients, more research is required.
========================================================
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
· Recurrent leukemia after allogeneic bone marrow transplantation.
· Treatment against CMV infection in SOT recipients.
· Treatment of PTLD caused by Epstein–Barr virus.
I note that adoptive transfer of immunity holds a lot of promise in a range of disorders in transplant recipients
Introduction :
Viral infection, including cytomegalovirus (CMV), BK virus, and Epstein-Barr virus, remains a significant cause of morbidity and mortality in immunocompromised individuals. While in immunocompetent individuals, latent CMV infection is controlled by the immune system. The incidence of CMV reactivation/reinfection in SOT is 16–56%
A cell-mediated immune response is considered the most critical arm of the immune system against CMV infection.
USE OF ADOPTIVE TRANSFER OF CMV-SPECIFIC T-CELLS IN THE CONTEXT OF SOLID ORGAN TRANSPLANTATION:
CMV-specific T-cell adoptive transfer is currently being evaluated for clinical application, with promising results as a treatment for CMV infection and disease in ulcerative enteritis in primary immunodeficiency or pediatric retinitis caused by CMV.
Several clinical studies are currently conducted:
(i) A clinical trial (NCT03665675) including 20 HSCT and SOT recipients patients is conducted to study the effect of transferring allogeneic CMV-specific T lymphocytes on CMV infection or reactivation. The first results will be available at the end of 2021
(ii) A clinical trial (NCT02779439) with 25 patients enrolled to elucidate the biological efficacy of therapeutically administered most closely HLA-matched third-party donor-derived specific cytotoxic T lymphocytes (CTLs) targeting CMV, following allogeneic blood or marrow stem cell or SOT
(iii) A clinical trial (NCT04364178) including 25 patients assessing whether partially matched, ≥2/6 HLA-matched, viral-specific T-cells have efficacy against CMV in subjects who have previously received any allogeneic HSCT or SOT.
(iv) A clinical trial (NCT03266640) with 20 participants investigating the therapeutic role of CMV CTLs in children, adolescents, and young adults (CAYA) with refractory CMV infection post allogeneic HSCT or SOT
CELLULAR THERAPIES AVAILABLE:
During the last years, a better understanding of CMV-specific T-cell immunology, such as the conserved T-cell epitopes
has led to the improvement of the methods for ex vivo T-cell culture
In addition, rapid tests to evaluate the effector function of the CMV-specific T-cells have become available
T-Cell Expansion:
To expand CMV-specific T-cells, it is crucial to define the most immunogenic epitopes used by the antigen-presenting cells (APC) to promote the activation and proliferation of peptide-specific T-cells.
Direct Selection Using Specific Peptide–MHC (pMHC):
Using pMHC multimers allows isolating of T-cells based on the T cells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules
Direct Selection Using Cytokine Capture System (CCS) :
CMV-specific T-cells can also be selected using IFN-g cytokine capture system (CCS), a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral antigens
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR):
This is the gene modification of a patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR). The generation of autologous CAR T-cells, which has also been explored as immunotherapy against CMV
Cell Therapy Limitations and Alternatives in SOT Patients:
The intensity and long-term immunosuppression requirement to prevent allograft rejection predisposes SOT recipients to a wide range of viral complications.
CONCLUSIONS :
Recent studies have significantly increased our knowledge about the protective role of CMV-specific T-cell immune response against CMV infection and disease
I like your summary
1- Summary:
Introduction:
During the last decade, many studies have demonstrated the role of CMV specific T-cell immune response on controlling CMV replication and dissemination. In fact, it is well established that transplanted patients lacking CMV-specific T-cell immunity have an increased occurrence of CMV replication episodes and CMV-related complications. In this context, the use of adoptive transfer of CMV-specific T-cells has been widely investigated and applied to Hematopoietic Stem Cell Transplant patients and may be useful as a therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia in patients receiving transplantation. However, only few authors have explored the use of T-cell adoptive transfer in SOT recipients.
Use of adoptive CMV- specific T cell therapy in SOT:
Four available studies have explored the use of T-cell adoptive transfer in SOT recipients. They included a very small number of patients. One study with promising results included 13 patients with CMV resistant to anti-viral drugs. And number of infusion ranged from 1- 6 infusions.
None reported major adverse events. They reported reduction of the viral load. Only one patients was reported to have lung graft failure and death from graft failure.
Together these results suggest that, although there is still space for improvement, the use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment.
Methods used to produce CMV-specific T cells:
1- T cell expansion:
It depends on defining the most immunogenic epitopes used by the antigen presenting cells (APC) to promote the activation and proliferation of peptide-specific T-cells. IE-1 and pp65 proteins are two of the most immunodominant CMV antigens and have been widely used to stimulate the CMV-specific immune response. Ex-vivo approach is preferred.
2- Direct Selection Using Specific Peptide–MHC (pMHC)
It allows isolating T-cells based on the T cells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules. HLA peptide tetramers from pp65 and IE-1 proteins have been previously used to select CD8+ T-cells that were further isolated using magnetic beads.
3- Direct Selection Using Cytokine Capture System (CCS)
– CMV-specific T-cells can also be selected using IFN-gamma cytokine capture system (CCS), a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral antigens.
– Different authors have successfully isolated functional CMV-specific T-cells using this method.
4- T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
– Other interesting strategie is the gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR).
– The generation of autologous CAR T-cells enables antigen recognition in a MHC independent manner and can be designed to specifically target conserved and essential epitopes of the selected antigen and overcoming pathogen escape mechanisms.
– While CAR-T-cell therapy identifies exclusively antigens located in the cell surface, TCR can also recognize intracellular antigenic fragments presented by MHC molecules.
– Further clinical studies will be necessary to demonstrate in vivo efficacy.
Limitations of cell therapy in SOT:
1- The deficiencies in T-cell differentiation and lifelong immunosuppression can affect to long-term survival of the transfused cells, interfering in the antiviral effect.
2- Some reported that in vitro generated CMV -specific CTL are highly sensitive to immunosuppressive drugs (such ascyclosporin A and FK506) impairing the production of effector cytokines.
3- Infusion of donor derive T-cells from donors may also transfer alloreactive T cells in numbers sufficient that could trigger episodes of rejection, particularly if the donor and the host differ in one or more HLA alleles
Over the past years third party donor T-cell banks have been established. Such banks permit selection of T-cells on the basis of HLA allele phenotype, viral specificity and HLA restriction, which may provide distinct advantages, particularly in the treatment of HLA non-identical recipients. Although it is still under study, the obtained results to date are highly promising
Conclusions:
– The role of CMV-specific T-cell immune reconstitution after SOT have demonstrated several benefits, including lower risk of CMV infection and graft rejection. Thus, the development and improvement of new CMV-specific T-cell transfer based therapies could be a useful to adjust the therapeutic interventions.
– Few studies are available which incorporated small number of patients with SOT who failed to respond to previous anti-viral medications. Although promising results were obtained, further development has been limited by due to difficulties of T cell expansion in SOT that are receiving immunosuppressive regimens, and the risk of graft rejection after T-cell administration.
– One possible approach to overcome these limitations is generating ready to use third-party CMV-specific T-cell banks to ensure the availability of well characterized the T-cell products
– Further work is clearly needed in order to fully understand and assess the clinical utility of these techniques in SOT recipients.
II- other roles of adoptive therapy in transplantation:
I note that adoptive transfer of immunity holds a lot of promise in a range of disorders
Introduction:
Viral infections caused by CMV, BKV, EBV and other virus lead to significant morbidity and mortality post transplant. Due to the suppression of the recipients immunity, the viruses are no longer held in check and can lead diseases or malignancies caused by these viruses. T cell immunity, which is the main target of the current immunosuppressive regimens, is affected and hence, predisposes to these viral infections.
CMV can affect multiple organs in the body and can also increase the risk of acute rejection.
There are specific CMV T cells that can control the infection and some authors have recommended to monitor these T cells for surveillance
Antiviral therapy has been used as prophylaxis and treatment of CMV disease but cases of resistance has been emerging and their use is also limited by their side effects
Use of Adoptive Transfer Of CMV Specific T Cells In SOT:
The use of CMV specific T cell adoptive transfer is currently being evaluated for clinical application in treatment of CMV infections in primary immunodeficiency with promising results.
In the context of transplantation, this therapy has been mainly investigated and applied to HSCT patients, both prophylactically, to reconstitute protective antiviral immunity, and as a treatment in patients with refractory CMV infection.
Few authors have explored the use of T cell adoptive transfer therapy in SOT patients. These studies have shown beneficial effects of this therapy when used in SOT recipients with CMV infections who had resistance to conventional therapies. Unfortunately these studies had very small numbers.
Currently, a number of clinical studies are being conducted to evaluate the efficacy and safety of this therapy.
Cellular Therapies
There are several methods to available to generate CMV specific T cells:
T-Cell Expansion:
To expand CMV specific T cells, its important to define the most immunogenic epitopes used by the APCs to promote the activation and proliferation of peptide-specific T cells. Currently, the ex vivo expansion method is used which reduces the presence of alloreactive or naive T cells in the final product. In addition, T cell ex vivo stimulation and expansion requires a small blood volume to establish the T cell culture.
Direct Selection Using Peptide-Specific -MHC (pMHC):
Using pMHC multimers allows to isolate T cells based on the TCR ability to bind a complex mixture of of peptide loaded recombinant HLA molecules. HLA peptide tetramers from pp-65 and IE-1 proteins have been used to used to select CD8+ T cells that were further isolated using magnetic beads. This method allows to reduce the time and improve the quality of the final product, minimizing alloreactivity.
Direct Selection Using Cytokine Capture System (CCS):
CMV specific T cells can be selected using IFN gamma cytokine capture system, a rapid assay that allows to select and enrich CD8+ and CD4+ INF gamma secreting T cells that have been previously stimulated using viral antigens. This strategy allows T cell selection thats in contrast with pMHC has no HLA restriction and as an additional benefit, stimulating and capturing a polyclonal population of CD4+ and/or CD8+ T cells depending on the Ag used for stimulation, using the streptamer strategy
T Cell generation Using Activation Marker And Engineered T Cells (CAR, TCR):
Other interesting strategies based on the successful performance for cancer treatment is the gene modification of the patients lymphocytes with tumor-specific T cell receptors (TCRs) or chimeric antigen receptors (CARs). The generation of autologous CAR T cells has which has also been explored as immunotherapy against CMV enables Ag recognition in a MHC independent manner and can be designed to specifically target conserved and essential epitopes of the selected Ag overcoming pathogen escape mechanisms
The other TCR strategy uses heterodimers integrated by alpha and beta peptide chains to recognize specific polypeptide fragments presented by MHC complexes. While CAR T cell therapy identifies exclusively antigens located in the cell surface, TCR can also recognize intracellular antigenic fragments presented by MHC molecules.
Cell Therapy Limitations And Alternatives In SOT:
Deficiencies in T cell differentiation and lifelong ISS can affect long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipients.
Different authors have demonstrated that in vitro generated CMV specific T cells are highly sensitive to the CNIs used impairing their effectiveness. A possible solution is to genetically modify the in vitro generated cells to confer resistance to these drugs. Alternatively, one can reduce the ISS drugs during the treatment with the adoptive therapy
Another limitation is associated with deficiencies of T cell differentiation in SOT recipients receiving ISS.
The other limitation is the risk of transfer of alloreactive T cells in numbers that could trigger rejection
The creation of third party cell banks as well as third party donor registries has emerged as a new possibility of treatment that employs T cells derived from partially HLA-matched third party donors
Conclusions:
Recent studies have significantly increased our knowledge about the protective role of CMV specific T cell immune response against CMV infection and disease. Thus, the use of T cell adoptive therapy may help to restore the CMV specific immunity for preventing and treating CMV infection in SOT individuals who don’t respond to the antiviral therapies or cant tolerate the antiviral therapies
Other Uses Of Adoptive Therapies In Transplant:
I note that adoptive transfer of immunity holds a lot of promise in a range of disorders
Summary:
CMV infection is one of the viruses that remains a major cause of morbidity and mortality in immunocopmromised patients.
The incidence of CMV activationin in SOT is having a median value of 30%..
CMV infection in addition of causing the direct effect due to its tissue proliferation and invasion, it can indirectly cause increased incidence of graft rejection and opportunistic infections or decrease recepient survival.
T cell mediated immune response is the most defence against against CMV infection.
There is increasing role of CMV specific- T cells in the defence against infection.
The use of available antiviral therapy are associated with some concerns related to the side effects and the emergence of resistance. Hence there is strong effort to search for new therapeutic options
Use of adoptive transfer of CMV- specific T- Cell in SOT:
This is well investigated and applied in HSCT patients but not in SOT.
Few studies have explored the use of T- cell adoptive transfer in SOT during the last decade but the results are promising. Based on this several clinical studies are nowb being conducted.
The results suggest that this approach is promising and there is still space for development in SOT.
Methodologies to generate CMV -specific T- cell
Limitations and alternatives in SOT:
Alternative is the generation of third party donor bank and registries as it can employs T- cell derived from partially HLA matched third part donor. This will allow to for ‘of the shelf” product. I also offers targeting multiple viral epitopes rather than monospecific approach,this carries the potentiality of increasing the antiviral effect.
Conclusion
Recent studies highlighted that the use of T- cell adoptive therapy may help to restore the CMV – specific immunity for preventing and treating CMV infections in SOT individuals who don’t respond to antiviral therapy. However further work is needed to asses the clincal utility of this therapy in SOT.
The role of adoptive immunotherapy in the manegemntvof different conditions related to transplantion:
I note that adoptive transfer holds a lot of promise.
Summary of the article
Is It Feasible to Use CMV-Specific T-Cell Adoptive Transfer as Treatment Against Infection in SOT Recipients?
This review article is about the impact of using CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients. Adoptive transfer of the oligoclonal T-cells were able to eliminate viremia, and infused cells persisted for up to two years
Strategies for the generation of CMV-specific T-cells.
A. Ex vivo T-cell expansion requires the in vitro stimulation and expansion of T-cells using APCs presenting viral peptides or proteins.
B. Direct selection employs virus-derived peptide specific multimers in the setting of a HLA class-I molecule, viral antigen T-cell stimulation followed by cytokine expressing T-cell selection using antibody coated immunomagnetic beads or activation marker selection based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation.
C. Genetic manipulation requires gene transfer of high affinity CMV-specific T-cell receptors (TCR) or chimeric-antigen receptors (CAR) to change specificity of T-cells to CMV antigens.
The methodology for cellular therapy
A. T-cell ex vivo stimulation and expansion: requires a small blood volume to establish the T-cell culture, making possible the generation of CMV-specific T-cells from low levels of circulating T-cells and naive donor sources.
B. Direct Selection Using Specific Peptide–MHC (pMHC)
Using pMHC multimers allows to isolate T-cells based on the T- cells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules.
C. Direct Selection Using Cytokine Capture System (CCS)
1) Using IFN- CCS, that allows to select and enrich CD8+ and CD4+ INF- secreting T-cells that have been previously stimulated using viral antigens.
2) Antigen stimulation based on the detection of specific surface molecules such as CD25, CD69, CD137 and CD154.
D. T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
Strategies based on the gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR).
1) TCR strategy uses heterodimers integrated by alpha and beta peptide chains to recognize specific polypeptide fragments presented by MHC complexes.
2) The generation of autologous CAR T-cells enables antigen recognition in a MHC independent manner and can be designed to specifically target conserved and essential epitopes of the selected antigen.
Cell Therapy Limitations and Alternatives in SOT Patients
a) in vitro generated CMV -specific CTL are highly sensitive to immunosuppressive drugs (such as cyclosporin A and FK506) impairing the production of effector cytokines.A possible solution in order to overcome this problem, is to:
1) genetically modify the in vitro generated CTL to confer resistance to these drugs.
2) decreasing patient ́s immunosuppression during a period post-infusion.
b) Deficiencies of T-cell differentiation in SOT recipients receiving immunosuppression.
The role of Adoptive immunotherapy in managing different conditions related to transplantation.
1. Adoptive immunotherapy is an attractive strategy not only to enhance antitumor responses but also to prevent GVHD and treat viral infections.
2. Immunotherapeutic strategy has been extended for multiple pathogens including cytomegalovirus, Epstein-Barr virus, adenovirus and BK polyoma-virus.
3. Has been used for relapses after allogeneic bone marrow transplantation.
4. Has been used to mediate response of established solid tumors.
5. Has been used for therapeutic benefit for renal cell carcinoma, melanoma, lung cancer, and breast cancer.
6. Treatment of EBV associated PTLD.
7. Treatment of Ganciclovir resistant CMV infection.
8. Host-directed strategies for treatment of tuberculosis.
I appreciate immense possibilities that adoptive immunotherapy promises as you describe in a spectrum of diseases.
Introduction
● Viral infection (CMV , BK , EBV) remains a major cause of morbidity and mortality in immunocompromised individuals
● The risk of CMV recurrent infections increases in :
☆ CMV seropositive allogeneic HSCT patients
☆ CMV seronegative SOT recipients from a seropositive donor
☆ HIV patients
☆ Patients who have received T-cell depletion therapy
● The incidence of CMV reactivation/reinfection is 30% in SOT and 37 % in HSCT
USE OF ADOPTIVE TRANSFER OF CMV-SPECIFIC T-CELLS IN THE CONTEXT OF SOLID ORGAN TRANSPLANTATION
● In SOT recipients
☆ T-cell response attenuation by IS drug
☆ (CTLs) activate alloreactive T-cells causing direct alloimmune injury
● Results suggest that use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment.
CELLULAR THERAPIES AVAILABLE
☆ conserved T-cell epitopes improve methods for ex vivo T-cell culture
☆ Rapid tests to evaluate the effector function of the CMV-specific T-cells have become available
☆ Methodologies available to generate CMV specific T-cells
● T-Cell Expansion
▪︎ IE-1 and pp65 proteins are the most
immunodominant CMV antigens used to stimulate the CMV-specific immune response
▪︎CMV-specific CD8+ T-cell clones were generated by stimulating donor (PBMC) with CMV-infected fibroblasts but it has risk of producing infection in patients. ▪︎poly-specific products targeting multiple antigens were generated
▪︎Recent T-cellex vivo stimulation and expansion has reduced the presence of alloreactive or naive T-cells in the final product and requires a small blood volume with low levels of circulating T-cells and naive donor sources
● Direct Selection Using Specific
Peptide–MHC (pMHC)
▪︎It need a previous knowledge about the immunodominance of the epitopes as pp65 and IE-1 proteins
▪︎This method :
• Reduce the time
• Improve the quality of the final product
• Minimizing alloreactivity
▪︎The disadvantages :
• limitation methods to isolate only CD8+ or CD4 T-cell populations
• The irreversibility of the binding can cause changes in the T-cell phenotype, leading to functional alterations of the purified T-cell population
▪︎ Streptamer technology in which there is no alteration of the phenotype or the functional status of the T-cells
Direct Selection Using Cytokine Capture
System (CCS)
▪︎This strategy has no HLA restriction and stimulating and capturing a polyclonal population of CD4+ and/or CD8+ T-cells depending on the antigen used for stimulation, not Streptamer strategy. ▪︎Isolation activated viral-specific T-cells based on specific surface molecules strongly up-regulated after T-cell activation such as CD25, CD69, CD137 and CD154
Cell Therapy Limitations and Alternatives
in SOT Patients
● Cell therapy may be an appropriate and effective alternative antiviral treatment.
● Genetically modify in vitro generated CTL to confer resistance to drugs
● Donor T-cell banks permit selection of T-cells on the basis of HLA allele phenotype, viral specificity and HLA restriction
FUTURE DIRECTIONS AND PERSPECTIVES
● Most informations available about adoptive CMV specific T-cell transfer
comes from HSCT recipients and Only few number of SOT recipients have used T-cell adoptive immunotherapy as a treatment of CMV infection or disease .
● SOT recipients enrolled previously failed to conventional treatment, with low survival rate.
● Development have been limited due to difficulties of T-cell expansion in SOT that are receiving immunosuppressive regimens, and the risk of graft rejection after T-cell administration.
● Approach to overcome these limitations is generating ready to use third-party CMV-specific T-cell banks to ensure the availability of well characterized the T-cell products
The role of adoptive immunotherapy in managing different conditions related to transplantation
* Prophylaxis of CMV when indicated
* Treatment CMV /Bk viremia/Disease after transplantation
* Treatment resistant CMV-disease
* Treatment of PTLD
* Treatment malignancies after transplantation
* Treatment of GVHD
* Protective role in adenovirus infection post-HSCT
Thank you.
Introduction: CMV infection is a major infectious complication of HSCT and SOT, increasing the risk of rejection, opportunistic infections, and recipient mortality.
SOT patients’ immunological (CMV-specific T-cells) and virological states may aid clinical decisions. CMV-specific T cells prevent infection and improve transplantation care.
Cellular treatment may help SOTP recipients restore their CMV-specific T-cell response.
SOT adoptive CMV-specific treatment.
Used in primary immunodeficiency ulcerative enteritis, pediatric CMV-retinitis, and HSCT prophylaxis or treatment of refractory CMV infection. SOT recipients have been less studied.
Autologous CMV-specific T-cells in lung transplant recipients with severe and chronic CMV pneumonia refractory to ganciclovir and foscarnet showed promise.
CMV-specific CTLs from third donors employed in KTRs (D+/R-) with refractory CMV infection resolved TMA characteristics, showing that SOT recipients may benefit from donor cell-banks.
The largest trial to date used T-cell adoptive treatment in SOT recipients (kidney, lung, and heart) with recurrent ganciclovir-resistant CMV infections. Immunological reconstitution was related with viremia control.
These promising outcomes have prompted additional HSCT and SOT clinical trials.
Cellular treatments
T-Cell Expansion: Define the APC’s most immunogenic epitopes to activate and proliferate peptide-specific T-cells to generate CMV-specific T cells.
Polyspecific products stimulated CMV-specific T-cells.
Direct Selection Using Specific Peptide–MHC (pMHC) Multimers — T-cells are isolated by their receptor (TCR) ability to bind a complex variety of peptide-loaded recombinant HLA molecules, decreasing alloreactivity.
Limitation; isolate only CD8+ or CD4 T-cell populations. Irreversible binding can modify T-cell phenotypic and function. Epitope-specific tolerance is dose-dependent.
Direct Selection Using Cytokine Capture System (CCS)
Choosing CMV-specific T-cells can be created utilizing Cytokine Capture System (CCS), a fast test that selects and enriches CD8+ and CD4+ INF-g secreting T-cells challenged with viral antigens.
Benefits: activating and capturing a polyclonal population of CD4+ and/or CD8+ T-cells without HLA restriction Detecting surface chemicals that are selectively expressed or substantially up-regulated following T-cell activation is another way to separate activated viral-specific T-cells.
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR) – Gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR) can target specified antigen epitopes.
Limitation: MHC presentation.
Cell Therapy Limitations and Alternatives in SOT Patients
SOT Cell Therapy Limitations:
T-cell differentiation and lifetime IS can impair transfused cell survival, antiviral function, and SOT recipients’ adoptive treatment.
How to address these limitations.
Genetically modified CTL to resist immunosupression
T-cells may expand and function once IS decreases post-infusion.
Generate CD8+ and CD4+ T-cells with polyfunctional effector capabilities to fight CMV infection.
Third-party cell banks allow treatment with partially HLA-matched donor T-cells.
Targeting many viral epitopes instead of one, potentially enhancing antiviral efficacy.
Future perspectives
CMV adoptive treatment in SOT demonstrated encouraging results in a few restricted studies.
T-cell growth in immunosuppressed SOT and graft rejection after T-cell delivery are challenges. Third-party CMV-specific T-cell banks overcome this.
Thank you.
Please summarise this article.
Introduction:
CMV infection either by virus reactivation in the recipient, or receiving the virus from the donor, are the most common ways, this virus is controlled by the T-cells that are targeted by the immunosuppressive medications (alemuzumab, ATG, … others) in HSCT and SOT, hence the prevelnce of CMV viremia and infection, increased in these patient., that is related to high morbidity, mortality and graft loss/rejection.
The treatment and prevention of the infection, have been addressed by literatures, by many antiviral therapy with side effects of neutropenia( ganciclovir), and nephrotoxicity(foscarnet and cidovovir), with some resistant strains difficult to treat.
This review highlights the role of CMV T-cell infusion in prevention and treatment of CMV infection in SOT.
USE OF ADOPTIVE TRANSFER OF CMV[1]SPECIFIC T-CELLS IN THE CONTEXT OF SOLID ORGAN TRANSPLANTATION:
– The effective application of CMV-specific partially HLA matched CTLs from third donors, suggesting that creating donor cell-banks could be useful as a therapeutic alternative in SOT recipients
– CMV-specific T-cells were isolated and stimulated with autologous PBMCs coated with HLA class I-restricted CMV peptide epitopes, based on patient´s HLA class I typing. The in vitro expanded T-cells showed an increase in HLA epitopes (A1, B7 and B35) and in the proportion of IFN-g+ CD107a+ cells that indicates the granule-dependent (perforin/granzyme) pathway of cytotoxic CD8+ T-cells.
– CMV viral load became undetectable, the patient’s usual immunosuppression regime was resumed, hepatic and bone marrow function remained normal with no evidence of acute rejection.
– The most ambitious study was performed in a cohort of 21 SOT recipients (13 kidneys, 8 lungs and 1 heart) who developed recurrent ganciclovir resistant CMV infections. Thirteen of these patients (8 D+/R-, 3 D+/R+ and 2 D-/R-) were subjected to T-cell (ranging from 22.2-245 × 106 T-cells) adoptive transfer receiving a maximum of 6 doses one of which discontinued therapy after a single dose, results in control of viremia, and reduction or even stopping the antiviral therapy, with negligible side effects.
CELLULAR THERAPIES AVAILABLE:
1. T-Cell Expansion:
Epitopes (pp65, IE-1,.. etc) used by the antigen presenting cells (APC) to promote the activation and proliferation of CMV-peptide-specific T-cells.
PROS: requires a small blood volume to establish the T-cell culture, making possible the generation of CMV-specific T-cells from low levels of circulating T-cells and naive donor sources.
CONS: only stimulated adoptive immunity against a single viral epitope, application may be limited for HLA-A2 patients/donors, and risk of producing infection later.
2. Direct Selection Using Specific Peptide–MHC (pMHC):
Using pMHC multimers allows to isolate T-cells based on the T[1]cells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules.
PROS: requires less time, good quality CMVTLS, safe to treat CMV infection in SOT.
CONS: isolates only CD8, or CD4 T-cells, irreversible cell binding may alter the function of the T-cells.
3. Direct Selection Using Cytokine Capture System (CCS):
A rapid assay that allows to select and enrich CD8+ and CD4+ INF-gamma secreting T-cells that have been previously stimulated using viral antigens.
PROS: no HLA restrictions, rapid, CD8 and CD4 (polyclonal) cells were obtained.
CONS: little clinical experience.
4. T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR):
The gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR).
PROS: antigen recognition in a MHC independent manner and can be designed to specifically target conserved and essential epitopes of the selected antigen, OVERCOMING pathogen escape, polyclonal cells were obtained.
CONS: The very low affinity to T-cell for the pathogen antigen, further studies required.
Cell Therapy Limitations and Alternatives in SOT Patients:
Deficiencies in T-cell differentiation and lifelong immunosuppression can affect to long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipients., can be overcome by:
· Genetically modify the in vitro generated CTL to confer resistance to IS drugs.
· Reducing the IS drugs dose.
· Promoting the generation of multiple polyfunctional effector functions that may be more effective in controlling CMV infection.
· The creation of third-party cell banks as well as third party donor registries has emerged as a new possibility of treatment.
Future direction and perspectives:
· Only few reports including a small number of SOT recipients have used T-cell adoptive immunotherapy as a treatment of CMV infection or disease, mandates further large population studies.
· Difficulties of T-cell expansion in SOT that are receiving immunosuppressive regimens, and the risk of graft rejection after T-cell administration.
· Generating ready to use third-party CMV-specific T-cell banks to ensure the availability of well characterized the T-cell products can overcome the aforementioned limitations.
Conclusions:
Adoptive therapy may help to restore the CMV-specific immunity for preventing CMV infection and treating for CMV infections in SOT individuals who have antiviral resistant CMV strains, with no alternative treatment available.
Generation of third party donor cell banks may help to use CMV-specific adoptive transfer as an alternative therapy for SOT recipients.
Further work is needed to address the clinical utility of these techniques in SOT recipients.
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
1. Treatment and prevention of CMV.
2. Treatment of PTLD.
3. Treatment of BKV.
4. Treatment of acute antibody mediated rejection.
5. Treating EBV related malignancies.
Thank you.
Introduction:
-CMV infection is one of the main infectious complications in HSCT and SOT, it can increased risk of rejection, opportunistic infections or decreased recipient survival.
– Monitoring both immunological (CMV-specific T-cells) and virological status may facilitate clinical decisions during follow-up of SOT recipients.
– Evidences demonstrate a role of CMV-specific T-cells in protecting from infection, and improve clinical care after transplantation. Therefore, the use of cellular therapy may be useful to reconstitute the CMV specific T-cell response in SOT recipients.
Use of adoptive CMV- Specific therapy in SOT.
– Used in treatment for CMV infection and disease in ulcerative enteritis in primary immunodeficiency, pediatric CMV-retinitis, and in HSCT as prophylactic or treatment of refractory CMV infection.
– The use in in SOT recipients it has been less investigated.
– Study in lung transplant recipient with a severe and persistent CMV pneumonia resistant to ganciclovir and foscarnet used autologous CMV‐specific T-cells showed promising results.
– CMV-specific CTLs from third donors used in KTRs (D+/R-) with refractory CMV infection showed good results with resolution of TMA features, suggesting that creating donor cell-banks could be useful as a therapeutic alternative in SOT recipients.
– The most ambitious study carried out to date was performed in SOT recipients ( kidney, lung and heart) who
developed recurrent ganciclovir resistant CMV infections, T-cell adoptive therapy used and showed evidences of immunological reconstitution was associated with control of viremia.
-Based on these promising results, several clinical studies are currently been conducted in HSCT and SOT.
Cellular therapies available
T-Cell Expansion
– Define the most immunogenic epitopes used by the APC to promote the activation and proliferation of peptide-specific T-cells is crucial to generate CMV-specific T cell.
– Polyspecific products targeting multiple antigens were generated to stimulate CMV- specific T-cells.
Direct Selection Using Specific Peptide–MHC (pMHC)
– Using pMHC multimers allows to isolate T-cells based on the T-cells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules
– HLA restricted, and minimizing alloreactivity.
– Limitation; isolate only CD8+ or CD4 T-cell populations, and the irreversibility of the binding can change T-cell phenotype, leading to functional alterations of T-cell population.
– It can cause epitope-specific tolerance in a dose dependent manner.
Direct Selection Using Cytokine Capture System (CCS)
– CMV-specific T-cells can produced by a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been stimulated using viral antigens
– Benefits; no HLA restriction, stimulating and capturing a polyclonal population of CD4+ and/or CD8+ T-cells
– Other selection strategy is to isolate activated viral specific T-cells based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation.
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
-Gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR), can be designed to specifically target epitopes of the selected antigen.
– Limitation : restricted to MHC presentation.
Cell Therapy Limitations and Alternatives in SOT Patients
Limitations:
Deficiencies in T-cell differentiation and lifelong IS can affect to long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipients
to overcome these issues:
– Genetic modification of generated CTL to confer resistance to these IS
– Decreasing IS during a period post-infusion may allow the expansion and functionality of T-cell.
– Promote the generation of CD8+ and CD4+ T-cells with multiple polyfunctional effector functions that may be more
effective in controlling CMV infection.
– Creation of third-party cell banks a new possibility of treatment that employs T-cells derived from partially HLA-matched donors.
– Targeting multiple viral epitopes rather than a monospecific approach, potentially increasing the antiviral effect
Future directions and perspectives;
-Few limited studies showed promising result with the use of CMV adoptive therapy in SOT.
-Challenges include difficulties of Tcell expansion in SOT that are receiving immunosuppressive regimens, and the risk of graft rejection after T-cell administration.
– Third-party CMV-specific T-cell banks can overcome this issue.
Conclusion:
The use of T-cell adoptive therapy may help to restore the CMV-specific immunity for preventing CMV infection in SOT
Different new techniques to generate CMV-specific T-cells and the possible generation of third party donor cell banks may help. Further studies is needed to assess the clinical utility of these techniques in SOT recipients.
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
– Treatment of CMV resistance infection/disease.
– Treatment and prevention of EBV+ PTLD, EBV, BK
– EBV associated malignancy
– Acute rejection
Reference:
-Catherine M. Bollard. Improving T-Cell Therapy for Epstein-Barr Virus Lymphoproliferative Disorders .Journal of Clinical Oncology . Volume 31, Issue 1
-Sadia Jahan et al.T-cell adoptive immunotherapy for BK nephropathy in renal transplantation .Transpl Infect Dis . 2020 Dec;22(6):e13399. doi: 10.1111/tid.13399
-Zang YW, Gu XD, Xiang JB, Chen ZY. Clinical application of adoptive T cell therapy in solid tumors. Med Sci Monit. 2014 Jun 10;20:953-9. doi: 10.12659/MSM.890496. PMID: 24912947; PMCID: PMC4063985.
Thank you.
Please summarise this article.
The role of CMV specific T-cell immune response on controlling CMV replication and dissemination is quite established . Those lacking CMV-specific T-cell immunity have an increased occurrence of CMV replication. The use of adoptive immune response can be used as a therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia.
This artivcle provides review of useful therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia.
Creating a T cell response
T-Cell Expansion
A large number of antigens expressed at different stages during viral replication participate in the activation of both CMV-specific CD8+ and CD4+ T-cells, known to mediate the immune response
CMV lysates or pp65-NLV peptide were used to stimulate CMV-specific T-cells
Adoptive transfer of the oligoclonal T-cells were able to eliminate viremia, and persisted for up to two years
Direct Selection Using Specific Peptide–MHC (pMHC)
This method allows to isolate T-cells based on the Tcells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules
Direct Selection Using Cytokine Capture System (CCS)
CMV speicific T cell are selected using IFN-g cytokine capture system (CCS), a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
It involves gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR)
Cell Therapy Limitations and Alternatives in SOT Patients
Use of long term immune suppression
Deficiencies of T-cell differentiation in SOT recipients receiving immunosuppression
Alternatives
Decrease immune suppression
genetic modification of in vitro CTL
Future directions and perspectives
The creation of third-party cell banks as well as third party donor registries
Conclusion
There is established role of CMV-specific T-cell immune response against CMV infection and disease
T-cell adoptive therapy may help to restore the CMV-specific immunity
It is important to know and understand limitations of such treatment
Thank you.
Summary
Introduction
Viral infections in the immunocompromised patient are a major cause of morbidity and mortality.
Highest risk of infections occur in CMV seropositive HSCT, D+/R- SOT, patients who receive T cell depleting agents, HIV infected individuals.
Risk of recurrence in SOT is at 16-56% while in HSCT is 30-70%.
CMV has both direct effects causing tissue invasive disease and indirect effects causing allograft rejection, opportunistic infections and decreased survival.
Cell mediated immunity is the corner stone to control CMV viremia.
Use in SOT
Much of the adoptive immunotherapy has been utilised in HSCT where it has been used for treatment and to reconstitute protection.
However its use in SOT is limited.
Studies done in SOT have shown that adoptive therapy can contribute to immune control in CMV infection.
Cellular therapies available
To generate and expand CMV specific T cells its important to define the most immunogenic epitopes which are IE-1 and pp65.
With adoptive transfer of oligoclonal T cells viremia is controlled and the transfused cells persisted for upto two years.
Using pMHC multimers allows to isolate T cells based on T cells receptor ability to load a complex mixture of peptide loaded recombinant HLA molecules.
This reduces time and improves quality of product.
CMV specific T cells are selected using IFN-ᵞ cytokine capture system, this allows T cells selection without HLA restriction.
Cell therapy limitations
May be addressed by decreasing the patients immunosuppression during the period post-transfusion allowing functionality and expansion of CMV specific T cells.
Can be addressed by generation of CD8 and 4 T cells displaying multiple effector functions.
This can be addressed by extensively culturing T cells to eradicate alloreactive cells.
Future directions
Role of CMV specific T cells immune reconstitution has demonstrated benefits in lowering CMV infections and incidence of graft rejection.
However most information come from HSCT with limited from SOT.
Though promising results, further development are limited by difficulties in T cell expansion and risk of rejection after administration.
This can be addressed by generation of third party CMV cell specific banks to ensure availability of well characterised products.
Conclusions
Studies have increased knowledge on protective role of CMV specific T cells on CMV disease.
T cell adoptive therapy may help prevent CMV infection and treatment in patients who don’t respond conventional therapies with no alternative treatments.
Further studies are required to further understand this therapy
Role of adaptive immunotherapy
Treatment of resistant CMV.
Prevention of CMV infection.
Prevention of GVHD in HSCT.
Treatment of EBV positive PTLD.
Thank you.
INTRODUCTION
Viral infection, including cytomegalovirus, BK virus and Epstein-Barr virus, remains a major cause of morbidity and mortality in immunocompromised individuals
While in immunocompetent individuals latent CMV infection is controlled by the immune system, in transplant recipients, both hematopoietic stem cell and solid organ transplantation (SOT), CMV infection is one of the main infectious complications.
CMV seropositive allogeneic HSCT patients presents the highest risk of recurrent infections, followed by CMV seronegative SOT recipients that receive a graft from a seropositive donor (R-/D+), HIV patients, and patients who have received T-cell depletion therapies.
Infection in SOT recipients?
A few authors have suggested the importance of monitoring patient’s CMV-specific immunity using standardized tools for individualizing the risk of CMV infection after transplantation
Using both immunological and virological patient monitoring may provide a wider knowledge of patients’.
Strong efforts have been made to search for new therapeutic approaches. In this context, the use of cellular therapy may be useful to reconstitute the CMV specific T-cell response and to control.
We provide a synthesis of recent data regarding the impact of using CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients, the different approaches to stimulate, isolate and expand CMV-specific T-cells developed over the years and a discussion of the possible use of CMV adoptive cellular therapy in these patients
Solid organ transplantation
The use of CMV-specific T-cell adoptive transfer is currently being evaluated for clinical application, with promising results as a treatment for CMV infection and disease in ulcerative enteritis in primary immunodeficiency or in pediatric retinitis caused by CMV.
After the infusion of the in vitro expanded T-cells no adverse events occurred, the CMV viral load became undetectable, the patient’s usual immunosuppression regime was resumed, hepatic and bone marrow function remained normal with no evidence of acute rejection
These results indicated that adoptive therapy can contribute to immune control of CMV infection.
The most ambitious study carried out to date was performed in a cohort of 21 SOT recipients (13 kidney, 8 lung and 1 heart) who developed recurrent ganciclovir resistant CMV infections
Thirteen of these patients (8 D+/R-, 3 D+/R+ and 2 D-/R-) were subjected to.
Together these results suggest that, there is still space for improvement, the use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment
Cellular therapies available
T-cell immunology such as the conserved T-cell epitopes, has led to the improvement of the methods for ex vivo T-cell culture.
CMV-specific CD8+ T-cell clones were generated by stimulating donor peripheral blood mononuclear cells (PBMC) with CMV-infected fibroblasts.
This approach was discontinued because of the risk of producing infection in patients.
Using the pp65-NLV peptide only stimulated adoptive immunity against a single viral epitope and its application may be limited for HLA-A2 patients/donors.
To overcome this problem, “polyspecific” products targeting multiple antigens were generated by incubating allogeneic T-cells in vitro with clusters of 15-mer peptides spanning the entire pp antigen to generate CMV-.
T-cell ex vivo stimulation and expansion requires a small blood volume to establish the T-cell culture, making possible the generation of CMV-specific T-cells from low levels of circulating T-cells and naive donor sources.
Direct selection using specific peptid-MHC
Cells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules.
It has been shown that pMHC multimer binding interferes with the functional status of epitope-specific T-cell population in vivo, causing epitope-specific tolerance in a dosedependent manner.
This intrinsic characteristic of pMHC multimer binding substantially limits the clinical application of this technology.
This issue has been further solved with the development of the Streptamer technology in which the binding of the HLA peptide and the antigen-specific TCR is reversed, by competing with a molecule that causes the Streptamer to monomerize, causing no alteration of the phenotype or the functional status of the T-cells.
This approach was shown to be safe to treat CMV infection in SOT patients, more research is needed.
Direct selection using cytokine capture
CMV-specific T-cells can be selected using IFN-g cytokine capture system (CCS), a rapid assay that allows to select and enrich.
Other selection strategy is to isolate and enrich activated viral specific T-cells after antigen stimulation based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation, such as CD25, CD69, CD137 and CD154.
Number of infusions
The patient developed a mild fever but no other adverse effects were noted and within 4 months his CMV viral load decreased from >5×10 6 copies to.
None of the patients who received adoptive CMV-specific T-cell therapy showed treatment-related grade 3, 4, or 5 adverse events.
Reduction or resolution of CMV reactivation and/or disease and improved response to antiviral drug therapy very low, which difficult the recognition.
To overcome this problem, modifications of the TCR using genetic engineering technology has been able to enhance the specificity and affinity of the recognition of the antigens by T-cells.
Cell therapy limitation and alternatives in SOT patients
The intensity and long-term immunosuppression requirement to prevent allograft rejection pre-disposes SOT recipients to a wide range of viral complications
Antiviral treatment can generate side effects such as nephrotoxicity, and the selection of drug-resistant mutant CMV strains, limiting treatment capability in SOT recipients.
Based on these limitations, cell therapy may be an appropriate and effective alternative antiviral treatment.
Different authors have demonstrated that in vitro generated
CMV -specific CTL are highly sensitive to immunosuppressive drugs impairing the production of effect or cytokines.
The creation of third-party cell banks as well as third party donor registries has emerged as a new possibility of treatment that employs T-cells derived from partially HLA-matched third party donors
The use of this method allows to achieve a rapid “off the shelf” product that could be used in a broader range of patients.
Over the past years third party donor T-cell banks have been established
Such banks permit selection of T-cells on the basis of HLA allele phenotype, viral specificity and HLA restriction, which may provide distinct advantages, in the treatment of HLA non-identical recipients.
It is still under study, the obtained results to date are highly promising
Activation marker
Rapid detection and enrichment of T-cells; broader repertoire of antigenspecific T-cells; Compatible with other assay formats; not restricted by HLA; not needed previous information of immunodominant epitopes; no specialized APC such as dendritic cells are needed.
Time-consuming and difficulty to isolate and expand functional cells; identification of novel T-cell epitopes often requires screening of a high number of epitopes
Genetically engineered
CAR-T Recognize antigens in an HLA-independent manner; target conserved and essential epitopes; infused to a broad range of patients irrespective of HLA.
Surface antigens can be targeted; restricted by epitope; expensive; Several toxicities.
TCR-T Wider range of targets; high affinity for specific antigens through genetic engineering; strong activation when a small amount of antigen is present; use of natural T-cell signaling mechanisms.
Expensive; time and labor-consuming; MHC restricted and depends on presentation by MHC molecules to recognize targets and activate T cell function; risk of hybridization between exogenous and endogenous chains
Future direction and prospective.
CMV is a major cause of severe complications in SOT recipients such as graft loss especially in patients that develop CMV infection with antiviral refractory CMV strains.
The role of CMV-specific T-cell immune reconstitution after SOT have demonstrated several benefits, including lower risk of CMV infection and graft rejection.
The development and improvement of new CMV-specific T-cell transfer based therapies could be a useful to adjust the therapeutic interventions.
Cell adoptive immunotherapy as a treatment of CMV infection or disease.
These studies enrolled SOT recipients that previously failed to conventional treatment, with low survival rate.
Better results should be obtained using T-cell adoptive immunotherapy in SOT recipients that had optimal clinical outcomes.
Conclusion
Recent studies have significantly increased our knowledge about the protective role of CMV-specific T-cell immune response against CMV infection and disease.
The use of T-cell adoptive therapy may help to restore the CMV-specific immunity for preventing CMV infection in addition to serve as a treatment for CMV infections in SOT individuals who do not respond to conventional therapies, such as patients infected with antiviral resistant strains with no alternative treatment available.
Recent findings regarding the development of new techniques to select, isolate and enrich functional CMV-specific T-cells and the possible generation of third party donor cell banks may help to use CMV-specific adoptive transfer as an alternative therapy for SOT recipients.
Further work is clearly needed in order to fully understand and assess the clinical utility of these techniques in SOT recipients
The role of adoptive immunotherapy;
1. Treatment of resistant case of CMV
2. PTLD, EBV, BK treatment
3. Acute rejection prevention
4. Prevention of GVHD
References
Is It Feasible to Use CMV-Specific T-Cell Adoptive Transfer as Treatment Against Infection in SOT Recipients?
Este ́ fani Garcı ́a-Rı ́os , Marcos Nue ́ valos , Francisco J. Mancebo and Pilar Pe ́ rez-Romero
Post-transplantation lymphoproliferative disorders: Current concepts and future therapeutic approaches
Fedaey Abbas, Mohsen El Kossi, Ihab Sakr Shaheen, Ajay Sharma, Ahmed Halawa
Well done.
1. Please summarise this article.
Impact of CMV-specific T-cell adoptive transfer in SOT recipients:
Available T-cell treatments:
·In vivo expansion & generation of CMV-specific T-cells:
·Direct Selection Using Specific Peptide–MHC (pMHC)
·Direct Selection Using Cytokine Capture System (CCS)
The automated CliniMACS Prodigy platform:
·T-Cell Generation Using Activation Marker & Engineered T-Cells (CAR, TCR)
==========================
2. Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
Drawbacks linked to IS-treated SOT recipients’ impaired T-cell differentiation:
Well done.
Please summarise this article.
INTRODUCTION
-Viral infection, including cytomegalovirus (CMV), BK virus and Epstein-Barr virus, remains a major cause of morbidity and mortality in immunocompromised individuals .
-In transplant recipients, both HSCT and SOT, CMV infection is one of the main infectious complications.
– Direct effects of CMV proliferation causing viral syndrome and indirect effects cause increased incidence of graft rejection and opportunistic infections or decreased recipient survival .
-Cell mediated immune response is considered the most important arm of the immune system against CMV infection and CMV-specific T-cells important in protecting from infection.
USE OF ADOPTIVE TRANSFER OF CMV SPECIFIC T-CELLS IN THE CONTEXT OF SOT
-In SOT, CMV-specific T-cell transfer has been widely investigated and applied to HSCT patients, both prophylactically, and as a treatment in patients with refractory CMV infection.
-Few authors have explored the use of T-cell adoptive transfer
in SOT recipients during the last decade . The results indicated that adoptive therapy can contribute to immune control of CMV infection .
CELLULAR THERAPIES AVAILABLE
-During the last years a better understanding of the CMV-specific T-cell immunology such as the conserved T-cell epitopes , has led to the improvement of the methods for ex vivo T-cell culture .
T-Cell Expansion
-To successfully generate and expand CMV-specific T-cells, it is
crucial to define the most immunogenic epitopes used by the
antigen presenting cells (APC) to promote the activation and
proliferation of peptide-specific T-cells .
-IE-1 and pp65 proteins are two of the most immunodominant CMV antigens and have been widely used to stimulate the CMV-specific immune response .
– In the initial studies, CMV-specific CD8+ T-cell clones were generated
by stimulating donor peripheral blood mononuclear cells (PBMC) with CMV-infected fibroblasts .
– CMV lysates or pp65-NLV peptide were used to stimulate CMV-specific T-cells .
– T-cell ex vivo stimulation and expansion requires a small blood volume to establish the T-cell culture, making possible the generation of CMV-specific T-cells from low levels of circulating T-cells and naive donor sources .
Direct Selection Using Specific Peptide–MHC (pMHC)
-Using pMHC multimers allows to isolate T-cells based on the Tcells
receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules.
-This method allows to reduce the time and improve the quality of the final product, minimizing alloreactivity .
-The main disadvantages of this technique are related with the limitation of the method to isolate only CD8+ or CD4 T-cell populations, and the irreversibility of the binding that can cause changes in the T-cell phenotype.
-In the context of SOT, p-MHC multimers has been previously used using autologous T-cells harvested from lifelong immunosuppressed patients .The associated challenges of this method could be minimized by using partially HLA-matched CMV-specific T-cells obtained from a third party donor .
Direct Selection Using Cytokine Capture System (CCS)
-CMV-specific T-cells can be selected using IFN-g cytokine
capture system (CCS), a rapid assay that allows to select and enrich
CD8+ and CD4+ INF-g secreting T-cells .
– Different authors have successfully isolated functional CMV-specific T-cells using this method.
-Some selection strategy is to isolate and enrich activated viral specific
T-cells after antigen stimulation based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation, such as CD25, CD69, CD137 and CD154. -Other strategies based on the successful performance for cancer treatment is the gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR).
Cell Therapy Limitations and Alternatives in SOT Patients
-The intensity and long-term immunosuppression requirement to
prevent allograft rejection pre-disposes SOT recipients to a wide
range of viral complications .
-In addition, antiviral treatment can generate side effects such as nephrotoxicity , and the selection of drug-resistant mutant CMV strains , limiting treatment capability in SOT recipients.
-Different authors have demonstrated that in vitro generated
CMV -specific CTL are highly sensitive to immunosuppressive
drugs impairing the production of effector cytokines .
-Decreasing patient´s immunosuppression during a period post-infusion may allow the expansion and functionality of the CMV-specific T-cells.
-Third-party CMV-specific T cells can be used in patients that admit a reduction of the immunosuppression regimen without compromising the allograft stability.
-Another limitation is associated with deficiencies of T-cell
differentiation in SOT recipients receiving immunosuppression.
– Infusion of donor derive T-cells from donors may transfer alloreactive T cells in numbers sufficient that could trigger episodes of rejection, particularly if the donor and the host differ in one or more HLA alleles.
-The creation of third-party cell banks as well as third party donor registries has emerged as a new possibility of treatment that employs T-cells derived from partially HLA-matched third party donors .
FUTURE DIRECTIONS AND PERSPECTIVES
– The role of CMV-specific T-cell immune reconstitution after SOT have demonstrated several benefits, including lower risk of CMV infection and graft rejection.
-The development and improvement of new CMV-specific T-cell transfer based therapies could be a useful to adjust the therapeutic interventions.
-Most of the information of CMV specific T-cell transfer available
comes from studies in HSCT recipients . Only few reports including a small number of SOT recipients have used Tcell adoptive immunotherapy as a treatment of CMV infection or disease .
– Better results should be obtained using T-cell adoptive immunotherapy in SOT recipients that had optimal clinical outcomes.
-Results from the ongoing clinical trial analyzing the safety and feasibility of administering CMV specific- CTLs from haploidentical donors in transplant patients would be of importance to implement
T-cell adoptive therapy in SOT recipients.
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
1.Epstein-Barr Virus Lymphoproliferative Disorders
2.Resistant case of CMV.
3.BK nephropathy post kidney transplant
References
1.Catherine M. Bollard. Improving T-Cell Therapy for Epstein-Barr Virus Lymphoproliferative Disorders .Journal of Clinical Oncology . Volume 31, Issue 1
2. Sadia Jahan et al.T-cell adoptive immunotherapy for BK nephropathy in renal transplantation .Transpl Infect Dis . 2020 Dec;22(6):e13399. doi: 10.1111/tid.13399.
Well done.
Summary of the Article:
The Introduction:
The use of cellular therapy (CMV-specific T-cell response to control CMV viremia and disease.
Transplant recipients are exposed to a high risk of morbidity and mortality, due to viral infection, (BK, CMV, EBV) as their immunocompromised.
Recipients with seronegative and D+, ATG, and cyclophosphamide post-transplant are more susceptible of infection and reactivation.
The incidence of CMV reactivation and reinfection is more prevalent in HSCT than in SOT, with the incidence rate of 30-70% and 16-56% respectively.
Viral syndromes associated directly with CMV:
Viral and immunological monitoring provide a wider knowledge of patients’ clinical situations that may facilitate clinical decisions during follow-up.
Although advances in antiviral treatment against CMV in immunosuppressed recipients, there are still undesirable unavoidable side effects.
Adoptive transfer of CMV-specific T-cell in SOT:
The Strategies of adoptive immunotherapy:
The role of adoptive immunotherapy:
Well done.
This is a narrative review study (level 5) on ways to manipulate the recipient’s immune response with donor T lymphocytes with a specific stimulus for specific care, in the case of this work it would be the treatment of Cytomegalovirus.
The recipient’s inability to trigger an adequate response against CMV, either because it is a negative recipient who received a transplant from a donor previously exposed to the virus, or a positive recipient who used anti-lymphocyte drugs and reactivated the disease. Another reason is the difficulty in living with the side effects of the antiviral drugs available for CMV, there is a proposal to establish the donation of specialized T cells with a response against the virus
.
Activation of macrophages and antigen-presenting cells and stimulation of specific T cells trigger an immune response with specific epitopes leading to a better response against CMV. More complex and, consequently, more effective and specific models, such as CAR-T and TCR-T, are T cells modified by genetic engineering for a more specific effect, but at an extremely high cost.
Undoubtedly, these are very promising techniques with more effective results, minimizing the side effects of medications and immunosuppressants. Its high cost and the need for specific cell stimulation are major challenges to the popularization of this technique.
Currently, bone marrow transplantation is already successful with CAR-T cell therapies
Thank you Filipe
Introduction;
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CMV is a major cause of severe complications in SOT recipients such as graft loss especially in patients that develop CMV infection with antiviral refractory CMV strains (110, 111).
The intensity and long-term immunosuppression requirement to prevent allograft rejection pre-disposes SOT recipients to a wide range of viral complications . In addition, antiviral treatment can generate side effects such as nephrotoxicity , and the selection of drug-resistant mutant CMV strains , limiting treatment capability in SOT recipients. Based on these limitations, cell therapy may be an appropriate and effective alternative antiviral treatment.
The role of CMV-specific T-cell immune reconstitution after SOT have demonstrated several benefits, including lower risk of CMV infection and graft rejection. Thus, the development and improvement of new CMV-specific T-cell transfer based therapies could be a useful to adjust the therapeutic interventions .
Using CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients.
——————————————————————————————————-
The use of CMV-specific T-cell adoptive transfer is currently being evaluated for clinical application, with promising results as a treatment for CMV infection and disease in ulcerative enteritis in primary immunodeficiency or in pediatric retinitis caused
by CMV .
In the context of transplantation, CMV-specific T-cell transfer has been widely investigated and applied to Hematopoietic Stem Cell Transplant (HSCT) patients, both
prophylactically, to reconstitute protective antiviral immunity, and as a treatment in patients with refractory CMV infection .
In contrast, in SOT recipients it has been less investigated probably due to the T-cell response attenuation produced by the administration of the immunosuppressive
therapy. In addition, SOT recipients may not tolerate donor- derived cytolytic T lymphocytes (CTLs) due to the activation of cytokine-mediated stimulation of the alloreactive T-cells causing direct alloimmune injury .
Several clinical studies are currently been conducted:
—————————————————————————
(i) A clinical trial (NCT03665675) including 20 patients, both HSCT recipients and SOT recipients is been conducted, to study the effect of transferring allogeneic CMV-specific T lymphocytes on CMV infection or reactivation .
(ii) A clinical trial (NCT02779439) with 25 patients enrolled, to elucidate the biological efficacy of therapeutically administered most closely HLA-matched third-party donor-derived specific cytotoxic T lymphocytes (CTLs) targeting CMV, following allogeneic blood or marrow stem cell or SOT.
(iii) A clinical trial (NCT04364178) including 25 patients assessing whether partially matched, ≥2/6 HLA-matched, viral specific T-cells have efficacy against CMV in subjects who have previously received any type of allogeneic HSCT or SOT.
(iv) A clinical trial (NCT03266640) with 20 participants investigating the therapeutic role of CMV CTLs in children, adolescents and young adults (CAYA) with refractory CMV infection post allogeneic HSCT or SOT.
Together these results suggest that, although there is still space for improvement, the use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment.
.
CELLULAR THERAPIES AVAILABL ;
————————————————————
1-T-Cell Expansion.
Adoptive transfer of the oligoclonal T-cells were able to eliminate viremia, and infused cells persisted for up to two years .
2- Direct Selection Using Specific Peptide–MHC (pMHC).
Using pMHC multimers allows to isolate T-cells based on the T- cells receptor (TCR) ability to bind a complex mixture of peptide-loaded recombinant HLA molecules . This method allows to reduce the time and improve the quality of the final product, minimizing alloreactivity .
3- Direct Selection Using Cytokine Capture System (CCS).
CMV-specific T-cells can also be selected using IFN-g cytokine capture system (CCS), a rapid assay that allows to select and enrich CD8+ and CD4+ INF-g secreting T-cells that have been previously stimulated using viral antigens .
4- T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR).
Is based on the successful performance for cancer treatment is the gene modification of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR).
Cell Therapy Limitations and Alternatives in SOT Patients;
—————————————————————————————–
The imitations ;
————————
Deficiencies in T-cell differentiation and lifelong immunosuppression can affect to long-term survival of the transfused cells, interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipients.
The alternative ;
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1-In vitro generated CMV -specific CTL are highly sensitive to immunosuppressive
drugs (such as cyclosporin A and FK506) impairing the production of effector cytokines.
2- Third-party CMV-specific T- cells could be used in patients that admit a reduction of the immunosuppression regimen without compromising the allograft stability.
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation;
—————————————————————————————-
1- Prevention and treatment of EBV+PTLD .
2- treatment BK nephropathy .
3- CMV-infection treatment.
4-Prevention of rejection in living donor kidney transplant recipients .5- malignancies including HL, T/NK lymphoma and NPC as adjunctive therapy to chemotherapy and/or in relapsed patients .
Well done.
CMV is common viral infection with potential devastating consequences in immune-compromised patient particularly whose with hemopoietic stem cells transplantation HSCT with incidence ratio of 30-70% and solid organ transplantation with a similar ratio of 16-56%.
Risk factors:
Four major categories:
HSCT, D+/R- transplant, HIV patients and patients received lymphocytes depleting agents such as ATG and Alemtuzumab, or post Cyclophosphamide therapy.
CMV is linked to several morbidity syndromes including CMV syndome , pneumonitis, gastroentritis, retinitis ext.
Its an important etiology for allograft rejection.
cell mediated immunity is the front line immune system to control CMV virus , with CMV specific T lymphocytes are the major player mediating protection against CMV.
It was suggested that CMV specific immunity monitoring shell be part of the general assessment of risk to attract CMV infection.
Treatment:
Anti-virals is the main therapeutic against CMV infection. Nevertheless, its not safe with side effect of nephrotoxicity.
CMV specific lymphocytes confer a substituted therapeutic option to control CMV infection.
CMV- Specific T cells adoptive transfer :
Transfusing CMV specific T lymphocytes shell be enhancing and rebuilding the immune system response towards CMV . It was investigated in patients with SOT,
main drawbacks of this method is T-cell response faltered owing to concurrent use of immune suppressants and because of the potential activation of alloreative cells by transferring donor derived cytolitic T lymphocytes.
Well done.
Use of adoptive transfer of CMV-specific T cell in SOT:
Types of cellular therapy:
T-cell expiation:
Direct selection using specific peptide MHC(PMHC):
T-cell generation using activation marker & engineered T cell (CAR,TCR):
Limitation of cellular therapy & alternatives in SOT:
Future direction & prospective:
Role of adoptive therapy in transplantation:
Zang Y., Gu X., Xing J. and Chen Z. Clinical application of adoptive T cell therapy in solid tumor. Med Sci-Fi Monit,2014; 20: 953-959.
Burns D. and Crawford D. Epstein-Barr virus-specific cytotoxic T-lymphocytes for adoptive immunotherapy of post transplant lymphoproliferative disease. Blood Reviews, 2004;18(3): 193-209.
Well done Ban.
Please summarise this article.
Introduction
§ Cell mediated immune response is the most important arm of the immune system against CMV infection
§ CMV-specific T-cells have a role of protection from infection with improvement in clinical care after transplantation
§ A few studies have suggested the importance of monitoring patient’s CMV-specific immunity
§ It is an option of standard treatment because of adverse effects, resistance, and high cost
§ Aim of the study: address the impact of using CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients, and a discussion of the possible use of CMV adoptive cellular therapy in this SOT population
Use of adoptive transfer CMV-specific T-cells in SOT
· Widely investigated in HSCT (less in SOT)
· Several studies were conducted in CMV-specific T-cell transfer in SOT (methods were direct selection by IFN-γ capture, Ex vivo expansion from a third party donor, and Autologous Ex vivo expansion)
· The results were promising with response (no adverse effect of infusion and viral load decreased)
· Several clinical studies are ongoing
· The use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment
Cellular therapies
Strategies for the generation of CMV-specific T-cells include:
1. Ex vivo T-cell expansion
2. Direct selection
3. Genetically engineered cells
T-cell expansion
Requires the in vitro stimulation and expansion of T-cells using APCs presenting viral peptides or proteins
Advantages inclue:
1. Not restricted by HLA type
2. Small blood volume required
3. Naïve donor can be used
4. Generation of polyclonal T-cells
Disadvantages:
1. Extensive culture period
2. Seropositive donors required
Direct selection
Direct selection employs virus-derived peptide specific multimers in the setting of a HLA class-I molecule, viral antigen T-cell stimulation followed by cytokine expressing T-cell selection using antibody coated immunomagnetic beads or activation marker selection based on the detection of specific surface molecules that are selectively expressed or strongly up-regulated after T-cell activation
Using specific peptide-MHC (pMHC)
Advantages: No needed extensive ex vivo manipulation and undergo rapid expansion in vivo
Disadvantages:
1. Restricted by HLA type and streptamer
2. Seropositive donors required
3. High frequency of specific T-cells needed
4. Select for a limited repertoire of CD8+ cells
Using cytokine capture system (CCS)
Advantages:
1. No needed extensive ex vivo manipulation and undergo rapid expansion in vivo
2. Not restricted by HLA type
3. Isolation of polyclonal CD4+ and CD8+ cells
Disadvantages:
1. Requires seropositive donors
2. Large blood volumes needed
Using activation marker
Advantages:
1. Rapid detection and enrichment of T-cells
2. Broader repertoire of antigen-specific T-cells
3. Compatible with other assay formats; not restricted by HLA
4. Not needed previous information of immunodominant epitopes
5. No specialized APC such as dendritic cells are needed
Disadvantages:
1. Time-consuming and difficulty to isolate and expand functional cells
2. Identification of novel T-cell epitopes often requires screening of a high number of epitopes
T-cell generation using activation marker and engineered T-cell (CAR, TCR)
Requires gene transfer of high affinity CMV-specific T-cell receptors (TCR) or chimeric-antigen receptors (CAR) to change specificity of T-cells to CMV antigens
CAR-T: advantages are:
1. Recognize antigens in an HLA-independent manner
2. Target conserved and essential epitopes
3. Infused to a broad range of patients irrespective of HLA
Disadvantages:
1. Only surface antigens can be targeted
2. Restricted by epitope
3. Expensive
4. Several toxicities
TCR-T: advantages are:
1. Wider range of targets
2. High affinity for specific antigens through genetic engineering
3. Strong activation when a small amount of antigen is present
4. Use of natural T-cell signaling mechanisms
Disadvantages:
1. Expensive
2. Time- and labor-consuming
3. MHC restricted and depends on presentation by MHC molecules to recognize targets and activate T cell function
4. Risk of hybridization (mismatch) between exogenous and endogenous chains
Cell therapy limitations and alternatives
1. In vitro generated CMV -specific CTL are highly sensitive to immunosuppressive drugs (such as cyclosporin A and FK506) impairing the production of effector cytokines (genetically modify the in vitro generated CTL to confer resistance to these drugs or decreasing patient´s immunosuppression during a period post-infusion)
2. Deficiencies of T-cell differentiation in SOT recipients receiving immunosuppression (use the viral antigens UL123 (IE1) and UL83 (pp65), known to promote a strong T-cellular response)
3. Infusion of donor T-cells may transfer alloreactive T cells in numbers sufficient to trigger episodes of rejection (extensive culturing T cells or even establishing T-cell clones to eradicate alloreactive T cells)
Future directions and perspectives
1. Third-party CMV-specific T-cell banks
2. T-cell adoptive immunotherapy
Conclusions
CMV-specific T-cell has a protective role against CMV infection and disease. So, T-ell adoptive therapy may restore CMV-specific immunity for prevention and treatment in those failed to response to conventional therapy (antiviral resistance and no alternative)
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation
1. Prophylaxis and treatment of CMV Infection. It offers a new approach in treatment of drug-resistant or refractory viral infections, with early clinical trials showing promise with respect to efficacy and safety
2. BK virus nephropathy. It reduced BK viral load significantly. Early intervention may prove efficacious in BK virus nephropathy
3. EBV-associated lymphoproliferative disease. EBVSTs can be readily produced from seropositive donors using good-manufacturing practice (GMP)- compliant protocols and cryopreserved for future use
4. Prevention of acute rejection
Well done.
Summary
INTRODUCTION
Cytomegalovirus (CMV), BK virus, and Epstein-Barr virus are important causes of illness and death in immunocompromised people. In immunocompetent people, latent CMV infection is managed by the immune system), but in transplant patients, both hematopoietic stem cell (HSCT) and solid organ (SOT) recipients, CMV infection is a major infectious consequence. Allogeneic HSCT patients with CMV seropositivity have the highest risk of recurrent infections. This is followed by CMV seronegative SOT recipients who get grafts from seropositive donors (R-/D+), HIV patients, and T-cell depletion therapy recipients (alemtuzumab, anti-thymocyte globulin, or post-transplant cyclophosphamide).
CMV-specific T-cell transfer in solid organ transplantation.
The CMV-specific T-cell adoptive transfer is being tested as a way to treat CMV infections and illnesses in people with ulcerative enteritis, primary immunodeficiency, or pediatric retinitis.
The CMV-specific T-cell transfer has been studied and used in patients with hematopoietic stem cell transplants (HSCT) to restore protective antiviral immunity and treat CMV infections that don’t respond to other treatments.
A kidney transplant patient (D+/R-) with refractory CMV infection got partly HLA-compatible CMV-specific T-cells at 1.6 × 107 T-cells/m2 from a third donor. Nineteen days after the infusion, the CMV DNA viral load dropped fiftyfold, and plasma exchange was stopped due to remission of thrombotic microangiopathy hematological characteristics (platelets 269 × 109/L, LDH 369 IU/L, no red cell fragments on blood film). Four weeks following the infusion, patients were released. CMV-specific CTLs from third-party donors worked, which shows that SOT users may benefit from donor cell banks.
T-Cell Expansion
Antigen-presenting cells (APC) must find the most immunogenic epitopes so that peptide-specific T-cells can become active and multiply. This is how CMV-specific T cells can be made and increased. During viral replication, several antigens activate CMV-specific CD8+ and CD4+ T-cells, which mediate the immune response.
Specific Peptide–MHC Selection (pMHC)
pMHC multimers can be used to separate T-cells by binding them to a complicated mix of peptide-loaded recombinant HLA molecules. This approach requires epitope immunodominance information due to HLA-type restrictions. HLA-peptide tetramers from pp65 and IE-1 proteins were utilized to identify CD8+ T-cells for magnetic bead isolation.
Selected Cytokine Capture System (CCS)
The IFN-g cytokine capture system (CCS) is a fast assay that selects and enriches CD8+ and CD4+ INF-g-secreting T-cells that have been primed with viral antigens to select CMV-specific T cells.
Engineered and Activation Marker-Generated T-Cells (CAR, TCR)
Another promising way to treat cancer is to change the genes of a patient’s lymphocytes to make them have tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors. (CAR). Autologous CAR T-cells may target conserved and crucial epitopes of the targeted antigen and overcome pathogen escape mechanisms.
Cell therapy limitation:
CD8+ and CD4+ T-cells with polyfunctional effector activities may better control CMV infection.
Donor T-cells may cause rejection.
T-cell clones may eliminate alloreactive T cells.
Third-party cell banks and donor registries cover numerous viral epitopes.
-possible nephrotoxicity.
the role of adoptive immunotherapy in managing different conditions related to transplantation
EBV-associated B-cell lymphoproliferative disease (BLPD)
Primary immunodeficiency disorders (PID) after HSCT ·
CMV and BK virus infection associated with transplantation
I like your reflections and summary. I wish you could type references to support your arguments.
CMV-specific T-cell immunity are deficient in transplanted patients thereby increasing CMV replication episodes.
Adoptive transfer of CMV-specific T-cells was introduced to Hematopoietic Stem Cell Transplant patients in order to control CMV viremia.
Introduction
CMV seropositive allogeneic HSCT patients, CMV seronegative SOT recipients (R-/D+), HIV patients, and recipients on T-cell depletion therapies are at high risk of CMV infections.
The CMV not only causes viral related syndrome ,but also can indirectly provoke graft rejection ,opportunistic infection and decrease recipient survival.
CMI is the main immune response for CMV infection ,therefore CMV specific T cells was adopted for CMV infection therapy.
Immunological along with virological status of the patient have to assessed to guide individualised therapy.
Available antiviral drugs have limitations as evolving of resistance and their side effects.
Therefore introducing CMV specific T cell therapy was adopted for CMV infection treatment in SOT recipients .
Adoptive transfer of CMV specific T-cells in SOT
It was introduced for CMV infection treatment and ulcerative enteritis treatment in primary immunodeficiency or in pediatric CMV retinitis and as prophylaxis or therapy for CMV infection in HSCT.
The possible role of T-cell adoptive transfer as a therapy in SOT recipients was studied.
A study conducted on D+/R-transplant with refractory CMV infection and thrombotic microangiopathy declared the effective role of CMV-specific CTLs from third donors in treating the CMV infection and thrombotic microangiopathy signifying that creating donor cell-banks can be a therapeutic alternative in SOT recipients.
Another study was done on lung transplant recipient (D+/R-)with ganciclovir resistant CMV infection treated with autologous invitro expanded T cells which had favourable outcomes.
Pierucci et al. introduced autologous T-cell transfer to a seronegative lung transplant recipient with a ganciclovir and foscarnet resistant CMV infection, along with cidofovir-related nephrotoxicity ,and the CMV viral load decreased.
Another study included 21 SOT recipients of variable organs as kidney ,heart and lung transplants suffering ganciclovir resistant CMV infection treated with CMV specific T cell and the CMV symptoms resolved and the antiviral drugs were reduced or stopped .
Multiple trials are undertaken for evaluating T cell therapy in HSCT and SOT .
Cellular therapies
Method s for ex vivo T cell culture involve
T-Cell Expansion
Antigen presenting cells (APC) use the most antigenic epitopes to activate and enhance proliferation of peptide-specific T-cells (CMV-specific CD8+ and CD4+ T-cells), different methods are used for in vivo expansion and generation of CMV-specific T-cells.
“Polyspecific” products aiming multiple antigens were obtained byincubating allogeneic T-cells in vitro with clusters of 15-merpeptides to produce CMV specific oligoclonal T-cells.
Direct Selection Using Specific Peptide–MHC (pMHC)
It enable isolation of T-cells based on the TCR ability to bind a complex mixture of peptide-loaded recombinant HLA molecules.
It requires immunodominace of epitopes knowledge and the methodology of CD4 and CD8 isolation is limited and binding can be irreversible thereby altering T cells and causing epitope specific tolerance but it was manged by Streptamer technology that can reverse the binding.
On the other hand it can save time and decrease alloreactivity.
Partially HLA-matched CMV-specific T-cells from a third party donor was used in CMV infection treatment in SOT.
Direct Selection Using Cytokine CaptureSystem (CCS)
CMV-specific T-cells can be obtained by using IFN-g cytokine capture system enabling selection and enhancement of CD8+ and CD4+ INF-g secreting T-cells stimulated by viral antigens without HLA restrictions and captures a polyclonal population of CD4+ and/or CD8+ T-cells.
Another method is to gather activated viral specific T-cells after antigen stimulation by detection of specific surface molecules selectively expressed after T-cell activation.
T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
Modifying the gene of patient’s lymphocytes with tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CAR) , it can be designed to aim certain epitopes of specific genes.
It’s draw back is that TCR T-cell therapy is restricted to MHC presentation.
Genetic engineering modifying TCR can enhance the specificity and affinity of the recognition of the antigens by T-cells as the affinity was low .
Cell Therapy Limitations and Alternatives in SOT Patients
T-cell differentiation deficiencies and lifelong immunosuppression affect the long-term survival of the transfused cells, and it’s antiviral functionality and cytokine produced.
In vitro genetic modification to theses CT cells and decreasing immunosuppressives post transfusion can solve this problem
Production of CD8+ and CD4+ T-cells harbouring multiple polyfunctional effector functions can be more efficient in controlling CMV infection.
Donor derive T-cells infusion to the recipient can trigger rejection episodes.
T-cell clones cultures to eradicate alloreactive T cells can be done.
Third-party cell banks from partially HLA-matched third party donors and third party donor registries are new treatment modalities that can cover multiple viral epitopes.
Future perspectives
CMV-specific T-cell therapy after SOT carries many advantages as decreasing the risk of CMV infection and graft rejection.
In fact studies on it’s use in SOT are limited meanwhile results were encouraging but difficulties of Tcell expansion in SOT receiving immunosuppressive regimens, and the risk of graft rejection after T-cell administration is a limitation.
Third-party CMV-specific T-cell banks can overcome that.
Conclusion
The awareness of the role of CMV specific T cell therapy in prophylaxis and treatment of CMV resistant infection in SOT is increasing and developing also more studies are done for this promising treatment modality.
– Role of Adoptive immunotherapy in managing different conditions related to transplantation.
· Prevention and treat human cytomegalovirus (HCMV) infection in bone marrow transplant recipients
· EBV-associated B-cell lymphoproliferative disease (BLPD)
· Primary immunodeficiency disorders (PID) after HSCT
· Adoptive immunotherapy with virus-specific T lymphocytes (VSTs) produces antiviral immunity after HSCT that is effective for treatment or prevention of viral infections with CMV, EBV, and adenovirus (AdV) with minimal risk of GVHD .
Reference
-Haque T etal .THE ROLE OF ADOPTIVE IMMUNOTHERAPY IN THE PREVENTION AND TREATMENT OF LYMPHOPROLIFERATIVE DISEASE FOLLOWING TRANSPLANTATION .British Journal of Haematology 1999 (106): 309-316
-McLaughlin LP, Bollard CM, Keller M. Adoptive T Cell Immunotherapy for Patients with Primary Immunodeficiency Disorders. Curr Allergy Asthma Rep. 2017;17(1):3. doi:10.1007/s11882-017-0669-2
I like your reflections and summary.
SUMMARY
Introduction
SUMMARY
Introduction
Use of adoptive transfer of CMV-specific T cell in the context of SOT
Methods of generating CMV specific T cell
The first method used was in vivo, where CMV-specific CD8+ T-cell clones were generated by stimulating donor peripheral blood mononuclear cells (PBMC) with CMV-infected fibroblasts. It was stopped because of risk of producing an infection.
The following are the ex vivo expansion method which has reduce alloreactive effect:
Cell therapy limitation and alternative in SOT patient
The creation of third-party cell banks as well as third party donor registries has emerged as a new possibility of treatment that employs T-cells derived from partially HLA-matched third party donors. The allows rapid off shef use of the medication
Future direction and perspective
Most of the studies on adoptive CMV specific T cell transfer was done on HSCT with only few on SOT recipients.
The future direction will be to generate a ready made to use third part CMV specific T cell bank to ensure availability of well matched T cell products
Conclusion
The available body of knowledge has shown the protective role of CMV specific T cell immune response to CMV infection and disease
The role of Adoptive immunotherapy in managing different conditions related to transplantation
I like your reflections and summary. I wish you could type references to support your arguments.
Is It Feasible to Use CMV-Specific T-Cell Adoptive Transfer as Treatment Against Infection in SOT Recipients?
1-Please summarise this article:
Introduction;
-Viral infection, including cytomegalovirus (CMV), BK virus and Epstein-Barr virus, remains a major cause of morbidity and mortality in immunocompromised individuals.
-The incidence of CMV reactivation/reinfection in SOT is 16–56% , while in HSCT has been reported to be 30–70%.
-Cell mediated immune response is considered the most important arm of the immune system against CMV infection with increasing evidences demonstrating a role of CMV-specific T-cells in protecting from infection, which can contribute to improve clinical care after transplantation.
Methods to generate CMV specific T-cells;
–T-cell expansion:
-Many antigens expressed during viral replication play role in the activation of both CMV specific CD8+ and CD4+ T-cells, and are known enhance immune response against the virus. e.g. IE-1 & pp65.
-Direct selection using specific peptide – MHC (pMHC):
-T cells are isolated based on their ability to bind a complex mixture of peptide-loaded recombination HLA molecules.This may improve the quality of the final product but it is
only limited to isolation of CD8+ or CD+ T cell population.
-Direct selection using cytokine capture (CCS):
-This is based on INF-gamma cytokine system.
-It has no HLA limitation compared to pMHC.
-T cell generation using activation marker and engineered T-cells (CAR, TCR):
-The generation of CAR allows antigen recognition without the need of MHC and can be designed to specifically target conserved and essential epitopes of the antigen in question.
Use of Adoptive Transfer of CMV-Specific T-Cells in the Context of Solid Organ Transplantation;
-CMV is a major cause of severe complications in SOT recipients such as graft loss especially in patients that develop CMV infection with antiviral refractory CMV strains.
-The period early after the transplant is considered critical due to the high risk of infections associated with a high incidence of CMV.
-The role of CMV-specific T-cell immune reconstitution after SOT have demonstrated several benefits, including lower risk of CMV infection and graft rejection.
-Thus, the development and improvement of new CMV-specific T-cell transfer based therapies could be a useful to adjust the therapeutic interventions.
-However, despite the increasing interest on adoptive CMV specific T-cell transfer, most of the information available comes from studies in HSCT recipients.
-Only few reports including a small number of SOT recipients have used T-cell adoptive immunotherapy as a treatment of CMV infection or disease.
-Together these results suggest that, although there is still space for improvement, the use of CMV-specific T-cell adoptive transfer is promising in SOT recipients with limited options for CMV-infection treatment.
Cell Therapy Limitations and Alternatives in SOT Patients;
-The intensity and long-term immunosuppression requirement to prevent allograft rejection pre-disposes SOT recipients to a wide range of viral complications.
-In addition,antiviral treatment can generate side effects such as nephrotoxicity,and the selection of drug-resistant mutant CMV strains, limiting treatment capability in SOT recipients.
-Based on these limitations, cell therapy may be an appropriate and effective alternative antiviral treatment.
-However,deficiencies in T-cell differentiation and lifelong immunosuppression can affect to long-term survival of the transfused cells,interfering in the antiviral functionality and limiting its use for adoptive therapy in SOT recipients.
-Another limitation is associated with deficiencies of T-cell differentiation in SOT recipients receiving immunosuppression.
-One possible approach to overcome these limitations is generating ready to use third-party CMV-specific T-cell banks to ensure the availability of well characterized the T-cell products.
Conclusion;
-The use of T-cell adoptive therapy may help to restore the CMV-specific immunity for preventing CMV infection in SOT individuals who do not respond to conventional therapies, such as patients infected with antiviral resistant strains.
-Further work is clearly needed in order to fully understand and assess the clinical utility of these techniques in Sot recipients.
2–Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
–Adoptive immunotherapy uses EBV-specific cytotoxic T lymphocytes (EBV-CTLs) or donor lymphocyte infusion (DLI) in an attempt to kill dividing B cells in EBV-associated PTLD.
-Most data using this approach come from retrospective series and small observational studies in hematopoietic cell transplantation (HCT) recipients. In this population, prevention of and remission of EBV-induced PTLD have been achieved in this manner in as many as 90 percent of patients.
-The major complication of adoptive immunotherapy is acute and chronic graft-versus-host disease (GVHD).
-DLI may produce GVHD, which does not appear to be a problem with EBV-CTLs.
I like your reflections and summary. I wish you could type references to support your arguments. I appreciate your concern about the risk of causing graft Vs host disease.
Thanks my dear Prof;Ajay
I will be happy with your advice
my references;Uptodate;
adaptive immunotherapy in management of PTLD.
Good luck
CMV infection after transplantation is common; around one third of patients receiving organ may develop CMV infection
CMV infection can affect the outcome of SOT through various mechanisms :
The principle of adoptive immunotherapy in treatment of CMV infection after transplantation is using CMV specific cytotoxic T lymphocytes (ex vivo T-cell culture) or donor lymphocyte infusion to kill CMV infected cells.
The transfer of CMV-specific T-cell is widely used in Hematopoietic Stem Cell Transplant (HSCT) patients; on the other hand it is less studied in the settings of organ transplantation which may be explained by the rule of immunosuppression which may attenuate T cell response, moreover, infusion of donor lymphocytes may cause immune response and graft versus host disease
Side effects of adoptive immunotherapy
Cellular therapy available for generation of CMV specific T-cells:
1. T-cell expansion:
2. Direct selection using specific peptide – MHC (pMHC)
3. Direct selection using cytokine capture (CCS)
4. T-Cell Generation Using Activation Markerand Engineered T-Cells (CAR, TCR)
Cell Therapy Limitations and alternatives in SOT Patients
Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
1. Treatment of resistant and refractory cases of EBV+ PTLD cases
2. May be used for the treatment of acute rejection through infusing Treg cells
3. Treatment of resistant cases of CMV, BK nephropathy
I like your reflections and summary. I wish you could type references to support your arguments.
IV.Is It Feasible to Use CMV-Specific T-Cell Adoptive Transfer as Treatment Against Infection in SOT Recipients?
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Please summarise this article.
Introduction
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Use OF Adoptive Transfer OF CMV- Specific T-cells IN The Contex OF Solid Organ Transplantion
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Cellular Therapies Available
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T-Cell Expansion
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Direct Selection Using Specific Peptide–MHC (pMHC)
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Direct Selection Using Cytokine Capture Using Cytokine Capture System (CCS)
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T-Cell Generation Using Activation Marker and Engineered T-Cells (CAR, TCR)
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Cell Therapy Limitations and Alternatives in SOT
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Future Direction AND Perspectives
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Please address the role of Adoptive immunotherapy in managing different conditions related to transplantation.
Adoptive Immunotherapy:-
Adoptive Immunotherapy:-
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Conclusion
I like your reflections and summary. I wish you could type references after the heading ‘conclusions’.
Many thanks Prof.Sharma
Introduction
Methodologies to generate CMV specific T-cells
A.T-cell expansion:
B.Direct selection using specific peptide – MHC (pMHC):
C.Direct selection using cytokine capture (CCS):
D.T cell generation using activation marker and engineered T-cells (CAR, TCR):
Limitation of the cellular therapy & alternatives in SOT:
Limitations;
Alternative solutions;
Future directives & perspectives;
Conclusion:
How promising this approach of adoptive transfer is?
Thank you prof,
Very good input in relation to my question
Thank you prof
Many thanks Prof.Sharma
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Reference
Very good input in relation to my question
Thanks alot Prof.Sharma
Results of several trials show that although there is still space for improvement, use of CMV specific T cell adoptive transferase is promising in treatment of refractory CMV infection( with limited available option of treatment).