Torque Teno Virus (TTV) Infection

TTV has been recently identified as a causative agent of non-A to non-G hepatitis. However, the exact role of this virus in the pathogenesis of chronic liver disease (CLD) and the development of hepatocellular carcinoma (HCC) remain controversial. To clarify these issues, the prevalence of this virus and its impact on the severity of liver disease and development of HCC among Egyptian patients were assessed. The study was conducted on 84 patients with CLD and 22 with HCC. They were diagnosed by clinical, biochemical, ultrasonographic and histopathologic findings. Chronic liver disease patients were classified into: chronic hepatitis (CH=48), compensated cirrhosis (CC=12) and decompensated cirrhosis (DC=24). Serum samples were collected from all patients and from 80 healthy volunteers as controls. All samples were serologically tested for markers of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection. HBV DNA, HCV RNA and TTV DNA were detected either by nested or RTPCR assays. HCV serotyping was performed for 60 out of 85 HCV positive samples using an enzyme immunoassay. Among CLD and HCC patients, 85 had chronic HCV, 5 had chronic HBV and 10 had dual HCV and HBV infections. Coinfection with TTV was detected in 27%, 0% and 20% of patients respectively. TTV DNA was detected in 23.8%, 31.8% and 25.0% of CLD, HCC patients and healthy volunteers respectively. The prevalence of TTV infection in CLD and HCC patients did not significantly differ from that of healthy volunteers, however TTV infection was significantly higher among patients with CC (41.7%) compared to those with DC (16.7%) (P<0.05). No significant differences were detected among TTV infected and non-infected patients concerning demographic, clinical and virologic data. Moreover, TTV viraemia was not significantly higher in HCC-positive than in HCCnegative patients. In conclusion, TTV viraemia is a common finding among adult Egyptian patients with CLD, HCC as well as in healthy volunteers. Infection with TTV does not contribute to the severity of liver disease nor to causation of HCC. [Nature and Science. 2006;4(2):38-45].