Low cell binding ability of HCV is closely related to interferon treatment especially in patients with HCV genotype 2a/2b: A large series prospective study on Japanese patients with chronic hepatitis C

Background/Aims: We have previously shown that the quantity of antibody-free virion in the pre-treatment sera of the patients with chronic hepatitis C is a good predictive factor for the efficacy of interferon treatment. However, the biological significance of the free virion should be verified by a prospective study. Methods: We prospectively evaluated 152 consecutive patients with chronic hepatitis C who received a standardized interferon treatment, and analyzed the free virion and the binding titers, the ability of hepatitis C virus (HCV) to bind to the human lymphocytic cell line. Results: Sixty-five patients achieved a long-term sustained remission, 76 patients did not respond to the interferon therapy, and 11 patients dropped out. The sera from the patients with genotype 2a/2b had significanfly lower free virion and cell binding titers than those with genotype 1b. A multivariate analysis showed three independent variables associated with the interferon response; cell binding titer <10^0.5/ml, viral load <10^4.5 copies/50 μl, and genotype 2a/2b with odds ratios of 14.6, 11.8, and 9.8, respectively. Conclusions: The low level of in vitro cell binding ability of HCV helped to clarify the good responsiveness to interferon observed in patients especially with a high viral load of genotype 2a/2b.