Factors predictive of response to interferon-α therapy in hepatitis C virus type 1b infection

Interferon-α (IFN-α) has been used to treat hepatitis C Virus (HCV)-induced infection but has been effective in only about half of all patients. It is suggested that the different responses to IFN-α treatment in HCV infection may be influenced by HCV genotypes, HCV RNA titer at the beginning of IFN-α therapy, and the sequences of the interferon sensitivity determining region (ISDR). However, there have also been reports showing that these have no relation to an IFN-α effect. In a previous study, it was found that the nucleotide sequence variation in the hypervariable region (HVR) 1 of the HCV could predict the effect of IFN-α. In the present investigation, an attempt was made to determine the predictive factors of IFN-α therapy. Twenty-six patients with HCV infection were treated with IFN-α. Among these, 13 patients recovered after 3 to 6 months of IFN-α treatment, although the other 13 patients showed no response after 6 months of treatment with IFN-α. In order to determine the predictive factors of IFN-α therapy, the ALT levels, HCV genotypes, HCV serum titer, and the quasispecies of HVR 1 were compared between responders and non-responders. It is suggested that the variation in the HVR 1 and HCV serum titer can be used to predict the effect of IFN-α.