Prevalence and disease association of TT virus infection in Japanese patients with viral hepatitis

Abstract Prevalence and disease association of the TT virus (TTV) were studied in Japanese patients with various types of viral hepatitis. A total of 317 patients with viral hepatitis were analyzed, and the results were compared to those of 100 apparently healthy controls. TTV DNA in serum was measured by semi-nested polymerase chain reaction. Prevalence of TTV DNA was significantly higher in patients with hepatitis A (36%, 5/14), hepatitis B (35%, 35/101), hepatitis C (61%, 90/148), and non-A-E hepatitis (41%, 22/54) than in healthy controls (12%, 12/100), respectively. In each type of hepatitis, the prevalence did not differ between acute and chronic liver diseases, and did not increase with the complication of hepatocellular carcinoma. The clinical backgrounds did not differ between TTV DNA positive and negative patients, in patients with acute hepatitis or in those with chronic liver diseases. Similarly, no liver function test showed a significantly higher level of in TTV DNA positive patients than in negative ones. In conclusion, TTV infection was highly prevalent in patients with viral hepatitis, especially in those with hepatitis C. TTV was suggested to have a weak pathogenicity (or no pathogenicity), at least when co-infecting with an established hepatitis virus.