[Titration and genotyping of hepatitis C virus RNA in chronic hepatitis C patients treated with interferon]

In order to evaluate the relation of the response to IFN therapy with viral factors, we quantified and typed HCV-RNA in sera and liver specimens from hepatitis C patients treated with IFN by using the single tube polymerase chain reaction. Sustained serum aminotransferase (sALT) normalization was resulted in 11 (19.6%) of the 51 patients. At 6 months after IFN therapy, serum HCV-RNA was negative in 13 of 44 patients. The pretreatment serum HCV-RNA titers tended to be higher in no responders than in complete responders and partial responders. HCV-RNA concentration in the liver correlated with serum HCV-RNA quantity. HCV infections with type I, II, III, IV, II + III, III + IV or II + III + IV were detected in 0, 24, 9, 2, 9, 2 or 3 patients, respectively. Mixed infection with more than 2 genotypes of HCV was found commonly than previously reported. IFN therapy induced complete response in 6 (66.7%) of the 9 patients with type III infection, and this response rate was apparently higher than that in the patients infected with type II or mixed type of HCV. Serum HCV-RNA titers were significantly higher in the patients with type III infection than in the patients with type II or mixed type infection. These findings implied that the determinations of pretreatment serum HCV-RNA titers and HCV-genotypes could be useful to predict sALT improvement and HCV eradication by IFN therapy.