CELLULAR MECHANISMS OF PTLD IN TRANSPLANT RECIPIENTS

移植后淋巴增生性疾病(PTLD)是一种主要的并发症。 与实体器官和骨髓移植有关 严重的发病率和死亡率。PTLD的发病率为1-10% 取决于同种异体移植的类型和免疫抑制方案。 EB病毒(Epstein-Barr Virus，EBV)是PTLD的病原体， 范围从良性B细胞增生症到恶性淋巴瘤。这个 这项研究的目的是定义免疫改变， 有助于EB病毒相关B细胞淋巴瘤的自主生长。 有待研究的关键决定因素是细胞因子和免疫抑制 药物环孢素(CS)和FK506。完成目标外围设备 血液单个核细胞和一组EB病毒感染的自发性 从同种异体移植直接获得的淋巴母细胞系(SLCL) 患有PTLD的受助人将被利用。提出了三个具体目标。 第一，细胞因子作为SLCL自分泌生长因子的参与 将会被定义。中和抗体和可溶性受体将是 用于确定细胞因子在SLCL存活、增殖、 通过细胞增殖试验和细胞周期分析评价细胞死亡情况。 将特别关注细胞因子IL-6、IL-10和肿瘤坏死因子-α。 此外，IL-6和IL-10启动的信号转导通路 将通过Western blotting和电迁移率位移分析来确定。 这些实验将表征蛋白的激活和磷酸化。 JANUS蛋白酪氨酸激酶家族及其信号转导 EB病毒中的转导和转录激活因子(STAT)蛋白 转化的B细胞来自PTLD患者。第二，T细胞的作用 在对EB病毒感染的B细胞的生长调节方面，将进行检测。这个 辅助性T细胞的功能(细胞因子的产生和增殖) 对特定病毒多肽的应答以及同种异体激活的作用 T细胞对EBV感染的B细胞的生长情况将进行测定。第三, SLCL中的细胞生存蛋白将被鉴定和定量 Northern和Western印迹以及细胞内染色和流动 细胞学。IL-10及免疫抑制药物CS和 FK506，直接调控细胞存活蛋白和细胞的表达 生存能力，并保护B细胞淋巴瘤免受凋亡刺激，将是 已定义。了解导致PTLD的免疫机制 对于潜在的这种潜在的新疗法的开发是重要的 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.