B-Lymphocyte Immunotherapy in Islet Transplantation

胰岛移植中的 B 淋巴细胞免疫治疗

• 批准号: 7124606
• 负责人: Ali Naji
• 金额: $ 223.56万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-30 至 2009-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7124606
• 关键词: B lymphocyte; antibody formation; autoantibody; clinical research; clinical trials; cooperative study; diabetes mellitus therapy; enzyme linked immunosorbent assay; human subject; human therapy evaluation; immune tolerance /unresponsiveness; immunotherapy; insulin dependent diabetes mellitus; isoantibody; monoclonal antibody; pancreatic islet transplantation; patient oriented research; sirolimus; transplantation immunology

DESCRIPTION (provided by applicant): The Diabetes Control and Complications Trial (DCCT) established that the microvascular complications of diabetes can be prevented by maintaining near normal glycemic control in patients with type 1 diabetes (T1D). This seminal outcome has provided a strong impetus for developing effective tolerogenic strategies for a cell replacement via pancreas or isolated islet transplantation in T1D patients. The recent success of the "Edmonton protocol" was a major advance in the field of islet transplantation. However, despite initial achievement of an insulin independent state, a progressive loss of beta cell function culminates in the recurrence of diabetes in a majority of these recipients. Thus, the Edmonton approach, which targets the T lymphocyte compartment alone, seems insufficient in preventing immunological rejection and recurrent anti-beta cell autoimmunity. Despite the critical role of T lymphocytes in these two processes, it is established that a concomitant and specific B lymphocyte response against beta-cell derived allo- and auto-antigenic epitopes also occurs. In rodent studies we demonstrated that interruption of B lymphocyte function curtails the T cell mediated destruction of islet allografts. Thus, we hypothesize that an induction immunotherapy regimen which targets both the B- and T lymphocyte compartments, will promote immunological tolerance to islet allografts. Our preclinical studies test this premise in non-human primates (NHPs) and indicate that the combined use of anti-B and T-lymphocyte antibodies (i.e., Rituximab and Thymoglobulin) results in long-term islet allograft survival without the need for maintenance therapy with a calcineurin inhibitor (CNI) agent. In the present application we propose to determine the efficacy of combined B- and T- lymphocyte directed immunotherapy for promoting immunological tolerance to islet allografts in T1D patients. We will initiate a clinical trial which will: 1) build upon our experience with the "Edmonton protocol", by incorporating the B lymphocyte specific monoclonal antibody, Rituximab, into its induction regimen and 2) assess the efficacy of a combined induction regimen including Thymoglobulin and Rituximab followed by CNI-free maintenance monotherapy with Rapamycin. Importantly, the latter protocol, which parallels that used in our preclinical NHP studies, will permit the inclusion of T1D patients with microalbuminuria into islet transplantation trials. A series of prospective in vivo metabolic studies will be undertaken to specifically evaluate beta cell function and secretory capacity following transplantation that 1) includes Rituximab and 2) eliminates CNI agents. Our mechanistic studies are designed to test the hypothesis that Rituximab immunotherapy provides a "tolerogenic window" for the reconstituting B lymphocyte repertoire, during which allo- and auto-reactive clones with a transitional phenotype are subject to negative selection. Following islet cell transplantation we will: 1) monitor the development of alloantibodies to HLA antigens and autoantibodies to islet antigens, 2) analyze the immunoglobulin repertoire for clonal persistence and heterogeneity using antibody CDR3 spectratyping, 3) survey the cytokine profiles of autoantigen-specfic T cells reactive to islet beta-cells by ELISpot, and 4) perform immunophenotyping and functional assays of circulating lymphocytes to assess global alterations in lymphocyte differentiation and energy. Overall, the proposed studies will determine whether a balanced immunotherapy regimen targeting the B- and T- lymphocyte compartments promotes a state of immunological tolerance to islet allografts, while obviating the need for chronic immunosuppression.

描述（由申请人提供）：糖尿病控制和并发症试验（DCCT）确定，可以通过维持1型糖尿病患者（T1D）的患者维持几乎正常的血糖控制来预防糖尿病的微血管并发症。这种开创性结果为T1D患者的胰腺或分离的胰岛移植提供了有效的耐受性策略，为开发有效的耐受性策略提供了强大的动力。 “埃德蒙顿协议”的最新成功是胰岛移植领域的重大进步。然而，尽管最初实现了胰岛素独立状态，但β细胞功能的进行性丧失在大多数受体中的糖尿病复发中均达到顶点。因此，仅针对T淋巴细胞室的Edmonton方法似乎不足以防止免疫排斥和反复发生的抗β细胞自身免疫性。尽管T淋巴细胞在这两个过程中的重要作用至关重要，但也确定对衍生出的同种和自身 - 抗原性表位的伴随和特定的B淋巴细胞反应也发生了。在啮齿动物的研究中，我们证明了B淋巴细胞功能的中断减少了T细胞介导的胰岛同种异体移植的破坏。因此，我们假设针对B-和T淋巴细胞室的诱导免疫疗法方案将促进对同种异体移植物的免疫学耐受性。我们的临床前研究在非人类灵长类动物（NHP）中测试了这一前提，并表明抗B和T-淋巴细胞抗体的总使用（即利妥昔单抗和胸腺胶质素）可导致长期同种异体移植物的生存，而无需维持钙尿素抑制剂（CNI）。在本应用中，我们建议确定B-和T-淋巴细胞联合定向免疫疗法的疗效，以促进T1D患者对胰岛同种异体移植的免疫学耐受性。我们将启动一项临床试验：1）通过将B淋巴细胞特异性单克隆抗体利妥昔单抗（利妥昔单抗）纳入其诱导方案和2）评估合并诱导方案的功效，包括胸腺素蛋白和RITUXIMAB，遵守CNIINICHINCN，将基于“ Edmonton方案”的经验，并将其纳入其诱导方案，并评估诱导方案的合并诱导方案的功效。重要的是，在我们的临床前NHP研究中使用的后一种方案将允许将微藻尿症的T1D患者纳入胰岛移植试验中。将进行一系列前瞻性体内代谢研究，以专门评估移植后的β细胞功能和分泌能力，即1）包括利妥昔单抗，2）消除CNI剂。我们的机械研究旨在检验以下假设：利妥昔单抗免疫疗法为重建B淋巴细胞库提供了一个“耐受性窗口”，在此期间，同种和自身反应性克隆具有过渡性表型是负选择的。以下胰岛细胞移植我们将：1）监测同抗向HLA抗原和自身抗体向胰岛抗原的开发，2）分析使用抗体CDR3频谱的抗体细胞对自动的抗体细胞的抗体CRONESTERS，分析子宫内持续性和异质性的免疫球蛋白曲率，以下ELISPOT和4）对循环淋巴细胞进行免疫表型和功能测定，以评估淋巴细胞分化和能量的全球变化。总体而言，拟议的研究将确定针对B-和T-淋巴细胞室的平衡免疫疗法方案是否促进了对胰岛同种异体移植的免疫耐受性的状态，同时避免了对慢性免疫抑制的需求。