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，通过维持1型糖尿病（T1 D）患者接近正常的血糖控制，可以预防糖尿病的微血管并发症。这一开创性的结果为开发T1 D患者中通过胰腺或分离的胰岛移植进行细胞置换的有效致耐受性策略提供了强大的动力。最近“埃德蒙顿方案”的成功是胰岛移植领域的一个重大进展。然而，尽管最初达到了胰岛素非依赖性状态，但在大多数这些接受者中，β细胞功能的进行性丧失最终导致糖尿病复发。因此，单独靶向T淋巴细胞区室的埃德蒙顿方法似乎不足以预防免疫排斥和复发性抗β细胞自身免疫。尽管T淋巴细胞在这两个过程中起关键作用，但已确定也发生针对β细胞衍生的同种异体和自身抗原表位的伴随和特异性B淋巴细胞应答。在啮齿类动物研究中，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物的破坏。因此，我们假设一种以B-和T淋巴细胞为靶点的诱导免疫治疗方案将促进对胰岛同种异体移植物的免疫耐受。我们的临床前研究在非人灵长类动物（NHP）中测试了这一前提，并表明联合使用抗B和T淋巴细胞抗体（即，利妥昔单抗和Thymoglobulin）可实现长期胰岛移植物存活，而无需钙调神经磷酸酶抑制剂（CNI）药物维持治疗。在本申请中，我们提出确定组合的B-和T-淋巴细胞定向免疫疗法在T1 D患者中促进对胰岛同种异体移植物的免疫耐受的功效。我们将启动一项临床试验，该试验将：1）基于我们在“埃德蒙顿方案”方面的经验，通过将B淋巴细胞特异性单克隆抗体利妥昔单抗纳入其诱导方案中，2）评估包括Thymoglobulin和利妥昔单抗的联合诱导方案的疗效，随后使用雷帕霉素进行无CNI维持单药治疗。重要的是，后一种方案与我们临床前NHP研究中使用的方案相似，将允许将微量白蛋白尿的T1 D患者纳入胰岛移植试验。将进行一系列前瞻性体内代谢研究，以专门评价移植后的β细胞功能和分泌能力，1）包括利妥昔单抗和2）消除CNI药物。我们的机制研究的目的是测试的假设，利妥昔单抗免疫治疗提供了一个“致耐受性窗口”的重建B淋巴细胞库，在此期间，具有过渡表型的同种异体和自身反应性克隆进行负选择。胰岛细胞移植后，我们将：1）监测针对HLA抗原的同种抗体和针对胰岛抗原的自身抗体的发展，2）使用抗体CDR 3谱型分析免疫球蛋白库的克隆持续性和异质性，3）通过ELISpot调查与胰岛β细胞反应的自身抗原特异性T细胞的细胞因子谱，和4）进行循环淋巴细胞的免疫表型和功能测定，以评估淋巴细胞分化和能量的总体改变。总体而言，所提出的研究将确定靶向B-和T-淋巴细胞隔室的平衡免疫治疗方案是否促进对胰岛同种异体移植物的免疫耐受状态，同时避免对慢性免疫抑制的需要。