title: Clinical significance of TT virus in chronic hepatitis C.
abstract: OBJECTIVE
  Much is still unknown about the clinical significance of TT virus (TTV), which has been reported as a candidate for non A-G hepatitis 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 underwent 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 neighbor-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 differences 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 with the ORF1 primer, and in 19.1% of patients with the 5' UTR primer at 6 months 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) concentrations were significantly correlated with changes in HCV-RNA in CHC patients with TTV. Moreover, there was no correlation between the changes in TTV DNA and the course of ALT.
  
  
  CONCLUSIONS
  Hepatocellular injury in patients with chronic hepatitis who are coinfected with HCV and TTV appears to primarily be caused by HCV and is less attributable to TTV.
authors.affiliation: First Department of Internal Medicine, Akita University School of Medicine, Akita City, Japan.
authors.forename: X W
authors.initials: XW
authors.lastname: Meng
authors.forename: M
authors.initials: M
authors.lastname: Komatsu
authors.forename: T
authors.initials: T
authors.lastname: Goto
authors.forename: K
authors.initials: K
authors.lastname: Nakane
authors.forename: S
authors.initials: S
authors.lastname: Ohshima
authors.forename: K
authors.initials: K
authors.lastname: Yoneyama
authors.forename: J G
authors.initials: JG
authors.lastname: Lin
authors.forename: S
authors.initials: S
authors.lastname: Watanabe
mesh_terms: D000328:Adult; D000410:Alanine Transaminase / Q000032:analysis; D004266:DNA Virus Infections / Q000188:drug therapy*; D005260:Female; D005500:Follow-Up Studies; D019698:Hepatitis C, Chronic / Q000188:drug therapy* / Q000821:virology*; D006801:Humans; D007372:Interferons / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D022783:Torque teno virus / Q000187:drug effects*
chemical_list: D007372:Interferons; D000410:Alanine Transaminase