Peripheral virus-specific T-cell interleukin-10 responses develop early in acute hepatitis C infection and become dominant in chronic hepatitis

Background/Aims: Interleukin-10 (IL-10) has been ascribed pro-viral but anti-fibrotic properties in chronic hepatitis C virus (HCV) infection. In this study, we examined the role of HCV-specific T-cell IL-10 response in patients with acute and chronic HCV infection. Methods: Peripheral HCV-specific T-cell IL-10 and IFN gamma responses were measured in cytokine Elispot assay using overlapping HCV-derived peptides in patients with chronic (n = 61), resolved (n = 15) and acute (n = 8) hepatitis C, looking for their onset, quantity, breadth and durability relative to clinical and virological outcomes. The source and effect of HCV-specific IL-10 response were determined in depletion and IL-10 neutralization experiments. Results: Both HCV-specific IL-10 and IFN gamma responses were detected early within 1-2 months of acute clinical hepatitis C. However, only HCV-specific IL-10 response correlated with elevated liver enzymes, increased viremia and suppressed HCV-specific CD4(+) T-cell proliferation in acute infection. While these associations were lost in established chronic infection, HCV-specific IL-10 responses were increased in patients without cirrhosis while IL-10 blockade enhanced antiviral effector IFN gamma responses. Conclusions:HCV-specific IL-10 Tr1 responses may play a dual role in HCV infection, dampening effector T-cells to promote viral persistence in acute infection but also protecting against progressive fibrosis in chronic infection. (c) 2008 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.