Immune Deregulation and Chronic Humoral Rejection of Kidney Allografts in Humans

描述（由申请人提供）：美国每年进行的肾移植数量正在增加。虽然早期移植物存活率在过去十年中有所改善，但长期存活率在同一时期没有显著变化，仍然不令人满意。越来越多的证据表明，慢性体液性排斥反应是造成晚期肾移植失败的主要原因。看起来，传统的免疫抑制疗法对甲流的反应并不好。更好地了解这种并发症的病理生理学将导致新的治疗方法的发展，并降低排斥反应的发生率。我们提出的研究的长期目标是了解导致CHR的免疫机制。CHR的特点是供体特异性抗体的发展。这些抗体可能是由针对同种异体移植物的CD 4 + T细胞依赖性B细胞应答产生的。然而，这种机制的直接证据很少。另一方面，调节性T细胞的缺陷导致人类异常的B细胞活化和自身抗体产生。自身抗体在移植受者中普遍存在。还已知用于预防排斥反应的免疫抑制药物直接损害Treg功能。我们认为，Treg缺陷导致外周B细胞失调，并伴随着同种抗体和自身抗体的产生，从而导致了CD 4 + T细胞减少。在一项综合分析中，我们的研究将确定Treg缺陷以及同种异体抗体和自身抗体的共同发展是否与肾移植受者的肾移植相关。我们还将研究Treg缺陷诱导CHR患者B细胞失调的可能机制。实验验证我们提出的模型将在3个具体目标中进行：Aim-1。检查是否与自身抗体滴度增加相关。利用蛋白质组学阵列的方法，我们将确定自身抗原的抗体反应在CHR的目标。然后，我们将评估这些目标的自身抗体的共同发展，以及与CHR的发生相关的同种抗体。目的-2。为了确定CD 4+细胞是否与Treg缺陷相关，患者样品中Treg群体的表型和分子评估将确定CD 4+细胞是否与这些细胞的数量和频率减少相关。还将使用基于体外细胞的测定来评估Treg抑制活性是否与Treg抑制活性降低相关。目标三为了确定B细胞失调的机制，B细胞亚群的表型和功能评估将确定是否失调在AML患者是由于缺陷的B细胞发育或外周B细胞活化加剧。基于体外细胞的测定将研究Treg控制B细胞活化的细胞机制。最后，我们将研究B细胞在CHR患者移植物中直接分化的可能性。

DESCRIPTION (provided by applicant): The number of kidney transplants performed every year in the US is increasing. While early graft survival has improved over the past decade, long-term survival has not significantly changed during the same time and remains unsatisfactory. Accumulating evidence suggests that chronic humoral rejection (CHR) is responsible for a large proportion of late kidney graft losses. Seemingly, CHR does not respond well to conventional immunosuppressive therapies. A better understanding of the pathophysiology of this complication will lead to the development of new treatments and reduce the rate of rejection. The long-term goal of our proposed research is to understand the immune mechanisms leading to CHR. CHR is characterized by the development of donor specific antibodies. These antibodies presumably result from a CD4+ T cell dependent B cell response directed to the allograft. Yet, direct evidence of this mechanism is scarce. On the other hand, deficiency in regulatory T cells leads to aberrant B cell activation and autoantibody production in humans. Autoantibodies are prevalent in transplant recipients. It is also known that immunosuppressive drugs used to prevent rejection, directly impair Treg function. We propose that CHR results from Treg deficiency leading to the deregulation of peripheral B cells and concomitant development of allo- and autoantibodies. In a comprehensive analysis, our studies will determine whether Treg deficiency and the co-development of allo- and autoantibodies correlate with CHR in kidney transplant recipients. We will also examine possible mechanisms whereby Treg deficiency induces B cells deregulation in patients with CHR. Experiments to verify our proposed model will be carried out in 3 specific aims: Aim-1. To examine whether CHR is associated with increased autoantibody titers. Utilizing a proteomics array approach, we will identify autoantigenic targets of antibody responses in CHR. We will then assess the co development of autoantibodies to these targets as well as alloantibodies in correlation with the occurrence of CHR. Aim-2. To determine whether CHR correlates with Treg deficiency Phenotypic and molecular assessment of Treg populations in patient samples will determine whether CHR correlates with reduced numbers and frequencies of these cells. In vitro cell based assays will also be used to assess whether CHR correlates with reduced Treg suppressive activity. Aim-3. To define mechanisms of B cell deregulation in CHR Phenotypic and functional assessment of B cell subsets will determine whether deregulation in CHR patients is due to defective B cell development or exacerbated B cell activation in the periphery. In vitro cell based assays will investigate the cellular mechanisms whereby Treg control B cell activation. Lastly, we will examine the possibility that B cells differentiate directly in the graft in patients with CHR.