Pegylated interferon α therapy in acute hepatitis C: Relation to hepatitis C virus-specific T cell response kinetics

Pegylated interferon α (PEG IFN-α) improves sustained virological response rates in chronic hepatitis C, but neither its role in acute hepatitis C nor the biologic basis for its action has been defined. This prospective study assessed the efficacy of PEG IFN-α treatment in acute hepatitis C in relation to the kinetics of hepatitis C virus (HCV)-specific CD4⁺ T cell responses during therapy and follow-up. Forty subjects with proven acute hepatitis C who received either PEG IFN-α plus ribavirin (n = 20) or PEG IFN-α monotherapy (n = 20) for 24 weeks in addition to 14 untreated subjects with acute hepatitis C were prospectively followed. Serum HCV RNA, HCV-specific CD4⁺ T cell responses, and cytokine production were measured before and during therapy and at follow-up and correlated to the outcome. The sustained virological response rate was 85% with PEG IFN-α/ribavirin combination and 80% with PEG IFN-α monotherapy. Five untreated subjects had spontaneous recovery. The frequency, magnitude, and breadth of HCV-specific CD4⁺ T helper 1 responses were significantly higher in treated subjects compared with untreated subjects with self-limited disease or subjects with chronic evolution. The CD4 ⁺ T cell responses were maintained in subjects with sustained virological responses and self-limited disease but fluctuated in those who developed chronic infection. In conclusion, PEG IFN-α therapy in acute hepatitis induces high rates of sustained virological response and prevents choronicity, probably through efficient early stimulation of multispecific HCV-specific CD4⁺ T helper 1 responses.