TT virus infection in hemodialysis patients

Recently, TT virus (TTV), associated with posttransfusion hepatitis, was discovered. Prevalence of TTV infection in maintenance hemodialysis (HD) units and its pathogenicity to liver was investigated.

A total of 115 patients on HD were assessed for presence of serum TTV. DNA was purified from sera, and nested polymerase chain reaction was done for the detection of TTV DNA.

TTV was detected in 59 patients on HD (51.3%), as compared with healthy blood donors (15 of 91 [16.5%], p < 0.0001). Serum HCV RNA and HBs antigen were positive in 16 and three patients, respectively. The prevalence rate of TTV was already 58.3% in the patients on HD for only 1 yr, and did not change according to the duration of HD until 15 yr on HD. TTV was positive in 51.2% (43 of 84) of the patients with history of blood transfusion, and in 51.6% (16 of 31) of those without it. In HCV-negative patients, alanine aminotransferase (ALT) levels of TTV-positive patients were similar to those of TTV-negative patients. Contrarily, in HCV-positive patients, ALT levels were more frequently > or =15 IU/L in TTV-positive patients (14 of 18) than in TTV-negative patients (five of 15) (p < 0.05).

TTV infection is remarkably prevalent in patients on HD and in healthy blood donors. It is suggested that TTV generally does not cause liver disease by itself, but there remains the possibility that TTV may aggravate liver disease caused by HCV.