Immune Response to Hepatitis C in Liver Transplantation

描述（由申请人提供）：全球估计有3亿人感染丙型肝炎病毒（HCV），相当大比例的感染者发展为肝硬化、肝衰竭和肝细胞癌（HCC）。这导致美国390万感染者中每年约8- 10，000人死亡。因此，在美国，HCV感染已成为肝硬化的主要原因，并且对于与HCV感染相关的已确定肝硬化的患者，肝衰竭的5年风险约为18%，HCC的5年风险约为7%。因此，HCV相关的肝功能衰竭已成为原位肝移植（奥尔特）最常见的适应症。因此，迫切需要更好地了解慢性HCV感染的发病机制，特别是在免疫功能低下的HCV感染的奥尔特受者的免疫介导的机制。本研究的具体目标是：1）明确HCV感染奥尔特受者的HCV特异性CD 4+和CD 8 + T细胞免疫应答，以验证缺乏HCV相关的同种异体移植物损伤与抗HCV CD 4+和CD 8 + T细胞应答的发展相关的假设。通过颗粒酶B、IFN-γ和IL-5 ELISPOT分析，在外周循环和移植物浸润细胞中评估HCV特异性CD 4+和CD 8 + T细胞应答。2)确定用于检测同种异体反应性和抗HCV反应性的免疫功能测定是否可以区分HCV复发和急性细胞排斥，因为这是当今HCV感染的奥尔特受体管理中存在的主要问题之一。为此，在怀疑排斥时，通过颗粒酶B、IFN-E]和IL-5 ELISPOT测定法在外周血以及移植物浸润淋巴细胞中测定CD 4+和CD 8 + T细胞同种异体反应性和/或HCV特异性反应性。3)明确HCV相关HCC患者的HCV特异性CD 8 + T细胞免疫应答，以检验HCC阳性患者与HCV感染的HCC阴性患者相比，HCV特异性CD 8 + T细胞反应性不同的假设。这些研究还将鉴定HCC细胞上表达的HCV衍生肽及其最常见的突变。该提案的总体目标是更好地定义免疫功能低下的奥尔特受者和HCC患者慢性HCV感染发病机制的免疫介导机制，这将有助于设计治疗这些疾病的新策略。此外，该项目旨在开发一种体外方法，用于区分HCV复发和奥尔特后的急性细胞排斥反应，这将对HCV感染的奥尔特接受者的管理产生直接的益处。

DESCRIPTION (provided by applicant): An estimated 300 million people worldwide are infected with hepatitis C virus (HCV) and a significant percentage of infected individuals develop cirrhosis, hepatic failure and hepatocellular carcinoma (HCC). This results in approximately 8-10,000 deaths annually among the 3.9 million infected individuals in the United States. HCV infection, thus, has emerged as the leading cause of cirrhosis in the United States and for patients with established cirrhosis related to HCV infection, the 5-year risk of liver failure is approximately 18% and that of HCC is approximately 7%. Therefore, HCV-related liver failure had become the most frequent indication for orthotopic liver transplantation (OLT). Therefore, a better understanding of the immune mediated mechanisms underlying the pathogenesis of chronic HCV infection, specifically in immunocompromised HCV-infected OLT recipients is urgently needed. The specific goals of this proposal are: 1) To define HCV-specific CD4+ and CD8+ T cell immune responses in HCV-infected OLT recipients in order to test the hypothesis that the lack of HCV-related allograft injury is associated with the development of anti-HCV CD4+ and CD8+ T cell responses. HCV specific CD4+ and CD8+ T cell responses will be assessed both in the peripheral circulation and in the graft infiltrating cells by means of granzyme B, IFN-n, and IL-5 ELISPOT analyses. 2) To determine whether immune functional assays for detection of alloreactivity and anti-HCV reactivity can differentiate between HCV recurrence and acute cellular rejection, since this is one of the main problems existing today in the management of the HCV-infected OLT recipient. Towards this, the CD4+ and CD8+ T cell alloreactivity and/or HCV-specific reactivity will be determined both in peripheral blood as well as in graft-infiltration lymphocytes at the time of suspected rejection by means of granzyme B, IFN-E], and IL-5 ELISPOT assays. 3) To define HCV-specific CD8+ T cell immune responses in patients with HCV-related HCC in order to test the hypothesis that HCC-positive patients will display a different profile of HCV-specific CD8+ T cell reactivity as compared to HCV-infected HCC-negative patients. These studies will also identify the HCV-derived peptides expressed on HCC cells and their most common mutations. The overall goal of this proposal is to better define the immune mediated mechanisms underlying the pathogenesis of chronic HCV infection in immunocompromised OLT recipients and HCC patients which will aid in designing new strategies for treatment of these diseases. Further, this project is intended to develop an in vitro method for differentiating HCV recurrence and acute cellular rejection following OLT that will have immediate benefit in the management of the HCV-infected OLT recipients.