Immune Response to Hepatitis C in Liver Transplantation

描述(申请人提供)：据估计，全球有3亿人感染丙型肝炎病毒(丙型肝炎病毒)，相当大比例的感染者会发展为肝硬化、肝功能衰竭和肝细胞癌(HCC)。这导致美国390万感染者中每年约有8-10,000人死亡。因此，在美国，丙型肝炎病毒感染已成为肝硬变的主要原因，对于与丙型肝炎病毒感染相关的既往肝硬变患者，5年内发生肝功能衰竭的风险约为18%，患肝细胞癌的风险约为7%。因此，丙型肝炎病毒相关性肝功能衰竭已成为原位肝移植最常见的适应证。因此，迫切需要更好地了解慢性丙型肝炎病毒感染的发病机制，尤其是免疫缺陷的丙型肝炎病毒感染的原位肝移植患者。这项建议的具体目标是：1)确定丙型肝炎病毒感染的原位肝移植受者中丙型肝炎病毒特异性的CD4+和CD8+T细胞免疫反应，以验证缺少丙型肝炎病毒相关的同种移植物损伤与抗丙型肝炎病毒的CD4+和CD8+T细胞反应的发展有关的假说。将通过颗粒酶B、干扰素-n和IL-5 ELISPOT分析评估外周循环和移植物浸润性细胞中的丙型肝炎病毒特异性CD4+和CD8+T细胞反应。2)确定检测同种异体反应性和抗-丙型肝炎病毒反应性的免疫功能分析能否区分丙型肝炎复发和急性细胞排斥反应，因为这是目前丙型肝炎病毒感染的原位肝移植患者治疗中存在的主要问题之一。为此，将通过颗粒酶B，干扰素-E]和IL-5 ELISPOT检测可疑排斥时外周血和移植物浸润性淋巴细胞中的CD4+和CD8+T细胞同种反应性和/或丙型肝炎病毒特异性反应性。3)明确丙型肝炎病毒相关性肝细胞癌患者的丙型肝炎病毒特异性CD8+T细胞免疫反应，以验证一种假设，即与丙型肝炎病毒感染的肝细胞癌患者相比，肝细胞癌阳性患者表现出不同的丙型肝炎病毒特异性CD8+T细胞反应。这些研究还将确定在肝癌细胞上表达的丙型肝炎病毒衍生多肽及其最常见的突变。这项建议的总体目标是更好地确定免疫低下的原位肝移植患者和肝细胞癌患者慢性丙型肝炎感染的免疫调节机制，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用于区分原位肝移植术后丙型肝炎复发和急性细胞排斥反应的体外方法，该方法将对感染丙型肝炎病毒的原位肝移植受者的管理产生立竿见影的效果。

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.