Influence of transfusion-transmitted virus infection on the clinical features and response to interferon therapy in Japanese patients with chronic hepatitis C

Recently, the genome of a novel DNA virus, transfusion-transmitted virus (T TV), was cloned from the plasma of a blood donor who had an elevated aminot ransferase level but no serological markers of known hepatitis viruses. In this study, we investigated the influence of TTV infection on the clinical features and response to interferon (IFN) therapy in patients with chronic hepatitis C. We studied 247 patients who had received a 16- or a 24-week co urse of IFN-alpha therapy. The serum of these patients was analysed for TTV DNA using a hemi-nested polymerase chain reaction and TTV was detected in 114 patients (46%). No significant differences were found with respect to c linical features (gender, age, liver-related biochemical tests, hepatitis C virus (HCV) genotype and serum HCV RNA levels) between the patients who we re positive for TTV DNA and those who were negative for TTV DNA. The fibros is score was higher in TTV-positive patients (2.1 +/- 1.1) than in TTV-nega tive patients (1.7 +/- 1.1, P = 0.023). The biochemical sustained-response rate was 25% in TTV-positive patients and 25% in TTV-negative patients (not significant). A sustained HCV clearance rate was achieved in 26% of TTV-po sitive patients and in 22% of TTV-negative patients (not significant). TTV DNA clearance after IFN therapy was observed in 36 of 69 patients (52%) for whom stored serum samples were available. The disappearance of TTV DNA had no effect on the biochemical response to IFN therapy. In conclusion, TTV c o-infection is frequently observed in Japanese patients with chronic hepati tis C. In chronic hepatitis C, TTV does not modify the clinical features or the response to IFN.