TT virus infection in chronic liver disease

BACKGROUND/AIMS: The exact role of the novel hepatotropic TT virus regardin g the etiology of viral hepatitis, as well as the progression towards chron ic liver disease has as yet not been defined. Moreover, the contribution of TTV infection to the course of chronic hepatitis B or C virus infections a lso still awaits clarification. Hence, the aim of our study was to investig ate the impact of TTV infection on clinical severity and histology of chron ic liver disease originating from HBV and/or HCV infections in Thai patient s concomitant with the determination of TTV's association with non-B, non-C chronic liver disease and compared to its prevalence among voluntary blood donors. METHODOLOGY: DNA was extracted from the sera collected from 115 hepatitis B patients, 41 hepatitis C, and 48 negative for either viral marker, who had all been diagnosed with chronic liver disease ranging from chronic hepatit is over cirrhosis to hepatocellular carcinoma. The sera obtained from 200 v oluntary blood donors served as controls. TTV DNA was amplified by seminest ed polymerase chain reaction (PCR) employing primers derived from the genom e's most conserved region. The PCR products were analyzed by gel electropho resis. Liver function tests were performed by means of a chemical analyzer. RESULTS: TTV DNA was detected in 20% of the HBV-positive and 19.5% of the H CV-positive chronic liver disease patients. Within the group of patients se ronegative for both viral markers, TTV was detected in 8.3%. Furthermore, i ts DNA was-identified in 6.8% of the HCC patients and finally, in 7% of the blood donors. Yet, no significant differences between TTV infected and non -infected patients were found as to demographic data, assumed source of inf ection, biochemical abnormalities, or severity of liver histology. CONCLUSIONS: TTV appears to be highly prevalent on a worldwide scale but re garding etiology of and progression towards serious liver disease, its cont ribution seems to be minor if not altogether nonexistent. Hence, regarding clarification of its clinical significance, further studies are certainly r equired.