Influence of TT virus co-infection on IFN-beta therapy in patients with chronic hepatitis C

Although results of IFN alpha therapy in chronic hepatitis C (C-CH) patients co-infected with TT virus (TTV) have been reported, no results of IFN beta therapy or IFN beta and alpha combination therapy have been reported. In this study, we retrospectively investigated whether co-infection with TTV affects the results of IFN therapy by using stored sera from 60 C-CH patients co-infected with TTV who underwent IFN beta therapy or IFN beta and alpha combination therapy. The stored sera were from 29 complete responders, 10 incomplete responders, and 21 non-responders, and they were used for qualitative and quantitative analysis of HCV RNA, HCV genotype analysis, and qualitative and quantitative analyses of TTV DNA. TTV DNA was detected in 23 (38.3%) of the 60 C-CH sera. The TTV DNA-positive rate was 17.2% among the complete responders to IFN therapy, versus 58.1% in the incomplete responders and non-responders, and the difference was significant (p < 0.01). While the complete response prediction rate based on two factors, HCV RNA level and HCV genotype, was 80.8% (21/26) in the C-CH patients, the prediction rate based on three factors, these two factors plus TTV DNA, was higher, 90.0% (18/20). It was concluded that determination of HCV RNA concentration, HCV genotype, and TTV DNA, before IFN beta therapy or IFN beta and alpha combination therapy is useful for predicting the results of treatment of C-CH patients.