Prevalence of TT virus infection in blood donors with elevated ALT in the absence of known hepatitis markers

OBJECTIVE: Recently a novel DNA virus (TT virus) has been identified in Jap an and shown to be associated with elevated aminotransferase levels after b lood transfusion. The exact role of TTV in the pathogenesis of liver diseas e is yet to be established. Our aim was to determine the prevalence and rol e of TTV in the pathogenesis of elevated transaminases in healthy blood don ors in the absence of markers for viral hepatitis A-C. METHODS: Stored sera were collected from 99 healthy blood donors with eleva ted alanine amino transferase (ALT) values that were discovered at the time of blood donation. A total of 146 samples were obtained from healthy donor s with normal ALT values who were used as controls. None of the patients or controls had a history of blood transfusion or had clinical signs of acute or chronic hepatitis. Serological markers for hepatitis A, hepatitis B, an d hepatitis C viruses were negative. TTV DNA was amplified and detected usi ng polymerase chain reaction followed by gel electrophoresis. RESULTS: Five of 99 (5%) samples obtained from donors with elevated ALT had TTV DNA detected by PCR, as compared to one of 146 (0.7%) of those with no rmal ALT (p = 0.006). Among those with elevated ALT, mean ALT values in pat ients with TTV (296 +/- 305 U/L) were higher than in patients without TTV ( 95 +/- 37 U/L), but the difference was not statistically significant (p = 0 .08). The two samples with highest ALT values (both >450 U/L) were among th e five samples with detectable TTV DNA in serum. CONCLUSIONS: Although TTV is not likely to explain the majority of elevated ALT cases in otherwise healthy blood donors, TTV infection may potentially be associated with some cases. Based on these findings, we propose that th e role of TTV in the pathogenesis of acute and chronic Liver diseases merit s further investigation. (Am J Gastroenterol 2000;95.772-776. (C) 2000 by A m. Cell. of Gastroenterology).