Relationship between pretreatment viremia level and response to interferon-alpha therapy in chronic hepatitis C differs in viral type 1 and 2 infections.

To determine the contribution of virus-related factors to long-term remission of chronic hepatitis C infection, we analyzed viral type and viremia level in 185 patients who had undergone a six-month course of interferon-alpha therapy. These virus-related factors were measured by an enzyme-linked immunosorbent assay with use of viral type-specific antigens and the branched DNA (bDNA) signal amplification assay, respectively. Sustained and long-term sustained responses were achieved in 55% and 50% of the patients, respectively. Transient or no responses were observed in 30% and 15% of the patients, respectively. Thirty-five percent of viral type 1 patients and 82% of viral type 2 patients had long-term sustained responses. Forty-two percent of bDNA-positive and 71% of bDNA-negative patients experienced long-term sustained responses. On multivariate analysis, viral type, Knodell's intralobular score, and viremia level were strong independent predictors of long-term sustained response (P < 0.0001, = 0.0060, and 0.037, respectively). Viremia level, however, was a significant predictor only in viral type 1, not type 2, patients. The relation between pretreatment viremia level and response to interferon-alpha therapy in chronic hepatitis C differs in viral type 1 and 2 infections.