Magnitude of activity in chronic hepatitis C is influenced by apoptosis of T cells responsible for hepatitis C virus

BACKGROUND: The mechanisms of hepatitis C virus (HCV) persistence are unknown, but down-regulation of immune response in a host is likely to play a major role in it. METHODS: To investigate whether T cell apoptosis contributes to such down-regulation, we compared peripheral T cell apoptosis in patients with chronic hepatitis C (CHC) with the serum titre of HCV-RNA, serum alanine aminotransferase (sALT) levels and its change, or peripheral T cell proliferation to the recombinant core antigen of HCV, JCC-1. RESULTS: The percentage of apoptosis in T cells was 0.30 +/- 0.31% (mean +/- SD) in 44 patients with CHC and 0.10 +/- 0.05% in 10 normal volunteers (P < 0.05). In patients with CHC there was no statistical correlation between apoptosis in T cells and sALT levels, titre of HCV-RNA or T cell proliferation to JCC-1 antigen. But, in patients showing relatively more apoptosis in T cells (more than mean + 2SD of apoptosis in T cells from normal volunteers), sALT levels decreased. CONCLUSIONS: Thus, T cell apoptosis in patients with CHC is considered to cause a reduction in sALT, contributing to HCV persistence in patients with CHC.