CELLULAR MECHANISMS OF PTLD IN TRANSPLANT RECIPIENTS

移植后淋巴组织增生性疾病（PTLD）是一个主要的并发症 实体器官和骨髓移植， 严重的发病率和死亡率。 PTLD的发生率为1-10% 这取决于同种异体移植物的类型和免疫抑制方案。 Epstein-Barr病毒（EBV）是PTLD的病原体， 其范围从良性B细胞增生到恶性淋巴瘤。 的 这项研究的目的是确定免疫改变， 有助于EBV相关B细胞淋巴瘤的自主生长。 需要研究的关键决定因素是细胞因子和免疫抑制因子 环孢素（CS）和FK 506。 为了完成目标外围 血液单核细胞和一组EBV感染的自发性 直接从同种异体移植物产生的淋巴母细胞系（SLCL） 将使用PTLD患者。 提出了三个具体目标。 第一，细胞因子作为自分泌生长因子参与SLCL 将被定义。 中和抗体和可溶性受体将 用于确定细胞因子在SLCL活力，增殖， 以及通过增殖测定和细胞周期分析评估的细胞死亡。 将特别关注细胞因子IL-6、IL-10和TNF-α。 此外，由IL-6和IL-10启动的信号转导途径 将通过蛋白质印迹和电迁移率变动测定来确定。 这些实验将表征 蛋白酪氨酸激酶（Jak）的Janus家族和信号传导 转导和转录激活因子（STAT）蛋白在EBV- 转化的B细胞。 二、T细胞的作用 将检测其在调节EBV感染的B细胞生长中的作用。 的 T辅助细胞的功能（细胞因子的产生和增殖） 特异性病毒肽的应答，以及同种激活的 将测定T细胞对EBV感染的B细胞生长的影响。 第三、 SLCL中的细胞存活蛋白将通过以下方法鉴定和定量： 北方和Western印迹以及细胞内染色和流式细胞术 细胞仪 IL-10和免疫抑制剂CS、 FK 506直接调节细胞存活蛋白和细胞凋亡的表达。 生存力，并保护B细胞淋巴瘤免受凋亡刺激，将是 定义了 了解导致PTLD的免疫机制 在开发新的治疗方法方面很重要， 移植的致命并发症

Post-transplant lymphoproliferative disorder (PTLD) is a major complication of solid organ and bone marrow transplantation and is associated with significant morbidity and mortality. The incidence of PTLD is 1-10% depending upon the type of allograft and the immunosuppressive regimen. Epstein-Barr virus (EBV) is the etiologic agent in PTLD, the spectrum of which ranges from benign B cell hyperplasia to malignant lymphoma. The objective of this research is to define the immune alterations that contribute to the autonomous growth of EBV-associated B cell lymphomas. The key determinants to be studied are cytokines and the immunosuppressive drugs cyclosporine (CS) and FK506. To accomplish the objective peripheral blood mononuclear cells and a panel of EBV-infected spontaneous lymphoblastoid cell lines (SLCL) generated directly from allograft recipients with PTLD will be utilized. Three specific aims are proposed. First, the participation of cytokines as autocrine growth factors for SLCL will be defined. Neutralizing antibodies and soluble receptors will be used to determine the role of cytokines in SLCL viability, proliferation, and cell death as assessed by proliferation assays and cell cycle analysis. Particular focus will be given to the cytokines IL-6, IL-10, and TNF-alpha. In addition, the signal transduction pathways initiated by IL-6 and IL-10 will be determined by Western blotting and electromobility shift assays. These experiments will characterize the activation and phosphorylation of the Janus family of protein tyrosine kinases (Jak) and the signal transducers and activators of transcription (STAT) proteins in EBV- transformed B cells from patients with PTLD. Second, the role of T cells in regulation of the growth of EBV-infected B cells will be examined. The function of T helper cells (cytokine production and proliferation) in response to specific viral peptides, and the contribution of allo-activated T cells to the growth of EBV infected B cells will be determined. Third, cell survival proteins in SLCL will be identified and quantitated by Northern and Western blotting as well as by intracellular staining and flow cytometry. The ability of IL-10, and the immunosuppressive drugs CS and FK506, to directly modulate expression of cell survival proteins and cell viability, and to protect B cell lymphomas from apoptotic stimuli, will be defined. An understanding of the immune mechanisms that contribute to PTLD is important in the development of novel therapies for this potentially fatal complication of transplantation.