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Basu S, Dudreuilh C, Shah S, Sanchez-Fueyo A, Lombardi G, Dorling A. Activation and Regulation of Indirect Alloresponses in Transplanted Patients With Donor Specific Antibodies and Chronic Rejection. Transpl Int 2024; 37:13196. [PMID: 39228658 PMCID: PMC11368725 DOI: 10.3389/ti.2024.13196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2024] [Accepted: 08/06/2024] [Indexed: 09/05/2024]
Abstract
Following transplantation, human CD4+T cells can respond to alloantigen using three distinct pathways. Direct and semi-direct responses are considered potent, but brief, so contribute mostly to acute rejection. Indirect responses are persistent and prolonged, involve B cells as critical antigen presenting cells, and are an absolute requirement for development of donor specific antibody, so more often mediate chronic rejection. Novel in vitro techniques have furthered our understanding by mimicking in vivo germinal centre processes, including B cell antigen presentation to CD4+ T cells and effector cytokine responses following challenge with donor specific peptides. In this review we outline recent data detailing the contribution of CD4+ T follicular helper cells and antigen presenting B cells to donor specific antibody formation and antibody mediated rejection. Furthermore, multi-parametric flow cytometry analyses have revealed specific endogenous regulatory T and B subsets each capable of suppressing distinct aspects of the indirect response, including CD4+ T cell cytokine production, B cell maturation into plasmablasts and antibody production, and germinal centre maturation. These data underpin novel opportunities to control these aberrant processes either by targeting molecules critical to indirect alloresponses or potentiating suppression via exogenous regulatory cell therapy.
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Affiliation(s)
- Sumoyee Basu
- Centre for Nephrology, Urology and Transplantation, King’s College London, London, United Kingdom
- Department of Inflammation Biology, King’s College London, London, United Kingdom
| | - Caroline Dudreuilh
- Centre for Nephrology, Urology and Transplantation, King’s College London, London, United Kingdom
- Transplantation, Renal and Urology Directorate, Guy’s and St Thomas’ NHS Foundation Trust, Guy’s Hospital, London, United Kingdom
| | - Sapna Shah
- Centre for Nephrology, Urology and Transplantation, King’s College London, London, United Kingdom
- Renal Unit, King’s College Hospital NHS Foundation Trust, London, United Kingdom
| | - Alberto Sanchez-Fueyo
- Department of Inflammation Biology, King’s College London, London, United Kingdom
- Liver Sciences, King’s College London, London, United Kingdom
| | - Giovanna Lombardi
- Centre for Nephrology, Urology and Transplantation, King’s College London, London, United Kingdom
- Department of Inflammation Biology, King’s College London, London, United Kingdom
| | - Anthony Dorling
- Centre for Nephrology, Urology and Transplantation, King’s College London, London, United Kingdom
- Department of Inflammation Biology, King’s College London, London, United Kingdom
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Negi S, Rutman AK, Saw CL, Paraskevas S, Tchervenkov J. Pretransplant, Th17 dominant alloreactivity in highly sensitized kidney transplant candidates. FRONTIERS IN TRANSPLANTATION 2024; 3:1336563. [PMID: 38993777 PMCID: PMC11235243 DOI: 10.3389/frtra.2024.1336563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 03/21/2024] [Indexed: 07/13/2024]
Abstract
Introduction Sensitization to donor human leukocyte antigen (HLA) molecules prior to transplantation is a significant risk factor for delayed access to transplantation and to long-term outcomes. Memory T cells and their cytokines play a pivotal role in shaping immune responses, thereby increasing the risk of allograft rejection among highly sensitized patients. This study aims to elucidate the precise contribution of different CD4+ memory T cell subsets to alloreactivity in highly sensitized (HS) kidney transplant recipients. Methods and results Stimulation of peripheral blood mononuclear cells (PBMC) with various polyclonal stimulating agents to assess non-specific immune responses revealed that HS patients exhibit elevated immune reactivity even before kidney transplantation, compared to non-sensitized (NS) patients. HS patients' PBMC displayed higher frequencies of CD4+ T cells expressing IFNγ, IL4, IL6, IL17A, and TNFα and secreted relatively higher levels of IL17A and IL21 upon stimulation with PMA/ionomycin. Additionally, PBMC from HS patients stimulated with T cell stimulating agent phytohemagglutinin (PHA) exhibited elevated expression levels of IFNγ, IL4 and, IL21. On the other hand, stimulation with a combination of resiquimod (R848) and IL2 for the activation of memory B cells demonstrated higher expression of IL17A, TNFα and IL21, as determined by quantitative real-time PCR. A mixed leukocyte reaction (MLR) assay, employing third-party donor antigen presenting cells (APCs), was implemented to evaluate the direct alloreactive response. HS patients demonstrated notably higher frequencies of CD4+ T cells expressing IL4, IL6 and IL17A. Interestingly, APCs expressing recall HLA antigens triggered a stronger Th17 response compared to APCs lacking recall HLA antigens in sensitized patients. Furthermore, donor APCs induced higher activation of effector memory T cells in HS patients as compared to NS patients. Conclusion These results provide an assessment of pretransplant alloreactive T cell subsets in highly sensitized patients and emphasize the significance of Th17 cells in alloimmune responses. These findings hold promise for the development of treatment strategies tailored to sensitized kidney transplant recipients, with potential clinical implications.
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Affiliation(s)
- Sarita Negi
- Infectious Diseases and Immunity in Global Health Program, Research Institute of the McGill University Health Centre, Montréal, QC, Canada
- Human Islet Transplantation Laboratory, McGill University Health Centre, Montréal, QC, Canada
| | | | - Chee Loong Saw
- HLA Laboratory, Division of Hematology, McGill University Health Centre, Montréal, QC, Canada
| | - Steven Paraskevas
- Infectious Diseases and Immunity in Global Health Program, Research Institute of the McGill University Health Centre, Montréal, QC, Canada
- Human Islet Transplantation Laboratory, McGill University Health Centre, Montréal, QC, Canada
- Department of Surgery, McGill University, Montréal, QC, Canada
- Division of General Surgery and Multi-Organ Transplant Program, Department of Surgery, McGill University Health Centre, Montréal, QC, Canada
| | - Jean Tchervenkov
- Infectious Diseases and Immunity in Global Health Program, Research Institute of the McGill University Health Centre, Montréal, QC, Canada
- Department of Surgery, McGill University, Montréal, QC, Canada
- Division of General Surgery and Multi-Organ Transplant Program, Department of Surgery, McGill University Health Centre, Montréal, QC, Canada
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