Negi Sarita, Rutman Alissa K, Saw Chee Loong, Paraskevas Steven, Tchervenkov Jean
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.
Front Transplant. 2024 Apr 8;3:1336563. doi: 10.3389/frtra.2024.1336563. eCollection 2024.
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.
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 TNF 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 γ, and, . On the other hand, stimulation with a combination of resiquimod (R848) and IL2 for the activation of memory B cells demonstrated higher expression of , α and , 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.
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.
移植前对供体人类白细胞抗原（HLA）分子致敏是延迟获得移植及影响长期预后的重要危险因素。记忆T细胞及其细胞因子在塑造免疫反应中起关键作用，从而增加了高敏患者同种异体移植排斥的风险。本研究旨在阐明不同CD4记忆T细胞亚群对高敏（HS）肾移植受者同种异体反应性的确切贡献。
用各种多克隆刺激剂刺激外周血单个核细胞（PBMC）以评估非特异性免疫反应，结果显示与非致敏（NS）患者相比，HS患者即使在肾移植前免疫反应性也较高。HS患者的PBMC在受到佛波酯/离子霉素刺激后，表达IFNγ、IL4、IL6、IL17A和TNF的CD4 T细胞频率更高，且分泌的IL-17A和IL-21水平相对较高。此外，用T细胞刺激剂植物血凝素（PHA）刺激HS患者的PBMC后，γ、 和 的表达水平升高。另一方面，通过定量实时PCR测定，用瑞喹莫德（R848）和IL-2联合刺激以激活记忆B细胞，结果显示 、α和 的表达更高。采用第三方供体抗原呈递细胞（APC）进行混合淋巴细胞反应（MLR）试验，以评估直接同种异体反应。HS患者中表达IL4、IL6和IL17A的CD4 T细胞频率显著更高。有趣的是，与缺乏记忆HLA抗原的APC相比，表达记忆HLA抗原的APC在致敏患者中引发更强的Th17反应。此外，与NS患者相比，供体APC在HS患者中诱导效应记忆T细胞的活化更高。
这些结果评估了高敏患者移植前的同种异体反应性T细胞亚群，并强调了Th17细胞在同种异体免疫反应中的重要性。这些发现为针对致敏肾移植受者的治疗策略的开发带来了希望，具有潜在的临床意义。
