Lymphocyte subset characterization associated with persistent hepatitis C virus infection and subsequent progression of liver fibrosis

This study aims to deepen the understanding of lymphocyte phenotypes related to the course of hepatitis C virus (HCV) infection and progression of liver fibrosis in a cohort of atomic bomb survivors. The study subjects comprise 3 groups: 162 HCV persistently infected, 145 spontaneously cleared, and 3,511 uninfected individuals. We observed increased percentages of peripheral blood TH1 and total CD8 T cells and decreased percentages of natural killer (NK) cells in the HCV persistence group compared with the other 2 groups after adjustment for age, gender, and radiation exposure dose. Subsequently, we determined that increased TH1 cell percentages in the HCV persistence group were significantly associated with an accelerated time-course reduction in platelet counts—accelerated progression of liver fibrosis—whereas TC1 and NK cell percentages were inversely associated with progression. This study suggests that TH1 immunity is enhanced by persistent HCV infection and that percentages of peripheral TH1, TC1, and NK cells may help predict progression of liver fibrosis.