Clinical significance of TT virus in chronic hepatitis C

Background and Aims: Much is still unknown about the clinical significance of TT virus (TTV), which has been reported as a candidate for non A-G hepat itis virus. The aim of this study was to clarify the clinical significance of TTV in patients coinfected with TTV and hepatitis C virus (HCV). Methods: The 95 subjects studied had chronic hepatitis C (CHC), and underwe nt interferon (IFN) therapy. TT Virus DNA was detected by using polymerase chain reaction. The nucleotide sequences were determined by using a dideoxy chain termination method. A phylogenetic tree was drawn up by using the ne ighbor-joining method. Results: TT Virus DNA was detected in 37.9% of patients with the use of an open reading frame 1 (ORF1) primer, and in 88.4% of patients by using a 5' untranslated region (5' UTR) primer. Using both sets of primers, no differe nces were found between TTV-DNA-positive and -negative subjects with CHC in the clinical findings. Serum TTV DNA was eradicated in 30.6% of patients w ith the ORF1 primer, and in 19.1% of patients with the 5' UTR primer at 6 m onths after the cessation of IFN therapy. The levels of TTV DNA before IFN therapy were significantly lower in the viral eradication group than in non -eradication group. The changes in alanine aminotransferase (ALT) concentra tions were significantly correlated with changes in HCV-RNA in CHC patients with TTV. Moreover, there was no correlation between the changes in TTV DN A and the course of ALT. Conclusion: Hepatocellular injury in patients with chronic hepatitis who ar e coinfected with HCV and TTV appears to primarily be caused by HCV and is less attributable to TTV. (C) 2001 Blackwell Science Asia Pty Ltd.