Effect of TT virus co-infection on interferon response in chronic hepatitis C patients

Aim: TT virus (TTV) is a single stranded DNA virus found in serum of patients with post-transfusion non-A to -G hepatitis. TTV-DNA has been investigated in sera of patients with various liver diseases. This study aimed at finding whether co-infection with TTV in HCV patients, may influence the effect of interferon (IFN) in complete elimination of HCV, and analysed the correlation between HCV and TTV by semi-quantification of both HCV RNAs and TTV DNA. Methods: In 28 chronic hepatitis C(CH-C) patients with TTV co-infection, the presence of TTV DNA was checked in sera six months before and after the end of IFN therapy. Result: Five out of 28 patients became negative for both HCV-RNA and TTV-DNA following IFN therapy. But 10 out of 28 patients persistently remained positive for both. Among the remaining 13 patients, 5 tested negative for HCV-RNA but positive for TTV-DNA. Post IFN therapy changes in serum alanine aminotransferase (ALT) levels did not appear to be influenced by the presence of TTV co-infection. HCV-RNA was found to be the most important predictor of IFN response in CH-C patients with TTV co-infection. TTV DNA level in sera had no correlation with IFN response. In addition, there was no relationship between HCV RNA and TTV DNA. Conclusion: Based on these results, it can be concluded that the effectiveness of IFN in eliminating HCV does not seem to be influenced by co-infection.