[Serum levels of HCV-RNA determined by branched DNA (bDNA) probe assay in chronic hepatitis C: method and clinical significance on interferon (IFN) therapy].

Recently serum levels of HCV RNA (s-HCV RNA) in chronic hepatitis C has been regarded as one of an important indicator for the activity of disease and outcome of IFN therapy. Quantitative analysis by competitive RT-PCR, however, requires special skills and is too expensive for clinical use. We attempted to determine serial sample of s-HCV RNA and genotypes in 117 cases treated with IFN using bDNA probe assay which has lately been developed by Chiron corporation. Cases with complete response to IFN therapy showed 62% (49/79) in lower than 10(6) levels, 27% (8/30) in 10(6)-10(7) and only 5% (2/41) in higher than 10(7). Genotype III, IV had higher response than type II on the same level of s-HCV RNA. These data indicates that determination of s-HCV levels by bDNA assay may be useful for prediction of the outcome of IFN therapy and making adequate schedule of the therapy in each cases.