Relation between reactivity to the NS-4 region peptides of hepatitis C virus (HCV) and clinical features among patients infected with HCV genotype 1b.

Nearly all patients infected with hepatitis C virus (HCV) genotype 1b have reactivity to the core (c22-3) or non-structural (NS)-3 region (c33c) protein in a second-generation recombinant immunoblot assay (RIBA-2). However, reactivities to the NS-4 region antigens (5-1-1, c100-3) vary among patients. To clarify whether differences in serological reactivities to the NS-4 antigens are associated with the clinical features or response to interferon (IFN) therapy of patients infected with hepatitis C virus (HCV) genotype 1b, we clinically investigated 115 such patients. Positive reactions to 5-1-1 and c100-3 were seen in 75.7 and 79.1%, respectively, of the patients. There were no differences between the patients with and those without antibodies to NS-4 region antigens (5-1-1, c100-3) with regard to age, duration of HCV infection, severity of liver disease and virus load. Fifty-one of the patients were treated with recombinant IFN-alpha, and 17 of the 51 patients showed sustained response to the therapy. The sustained response was more frequently seen in the patients positive for antibodies to both 5-1-1 and c100-3 as compared with those negative for either or both antibodies (41.0% vs. 8.3%, P<0.05).