Memory Phenotype of CD8+ T Cells in Chronic Hepatitis C Virus Infection

Abstract

About 170 million people are infected with hepatitis C virus (HCV), which may cause severe liver disease and liver cancer. 71 million individuals are chronically infected with important variations according to the geographical area. There is markedly high prevalence in the Middle East about 14.7% in Egypt. After acute infection, approximately 20% of infections are spontaneously cleared before the establishment of chronicity while a majority of healthy adults will develop persistent viremia. HCV-specific cytotoxic T lymphocytes play an important role in HCV control during acute infection. After the resolution of infection, a population of the virus-specific memory CD8+ T cells protects the host against reinfection. These subsets of memory cells differ with respect to their half-lives, their anatomical localization, their proliferative potential, their immediate effector function, their requirements for maintenance, their phenotype and their protective potential.

The aim of the present study is to identify the role of CD127, CCR7, CD45RA and CD45RO expressed on the CD8+ T cells in the clearance of HCV infection through studying the chronic HCV patients versus seronegative high-risk individuals. Our study included 60 individuals divided into 2 main groups: chronic HCV group (20 chronic HCV patients) and seronegative high risk group (40 healthcare workers “HCWs”). Both groups were subjected to flow cytometric analysis of PBMCs to determine the percentage of expression of CD3, CD8 and CD127 markers on CD8+ T cells. PBMCs from both groups were subjected to CFSE proliferation assay in response to HCV specific peptides(core, NS3\NS4, NS5) and the second group was divided into 2 subgroups according to proliferation index(cut-off<2) into: positive proliferation index high risk group (+PIHRG) (20 HCWs) and negative proliferation index high risk group (-PIHRG) (20 HCWs). Flow cytometric analysis