Influence of TT virus on the histopathological features of nonalcoholic fatty liver disease

The sera of 38 patients with nonalcoholic fatty liver disease (NAFLD) including nonalcoholic steatohepatitis (NASH), were tested for TT virus (TTV) DNA by polymerase chain reaction (PCR) using three different primer pairs (UTR PCR, N22 PCR and genotype-l PCR), and various histological features of the liver biopsy specimens were compared among those who were positive or negative for TTV infection. By UTR PCR which detects all TTV genotypes, TTV DNA was detected in 37 (97%) of the 38 patients. In contrast, N22 PCR which detects primarily TTV genotypes 1-4, detected TTV DNA in 18 patients (47%). In the liver biopsy specimens, moderate to many acidophilic bodies, moderate to marked focal/ spotty necrosis of hepatocytes and marked stellate, pericellular or perivenular fibrosis were observed significantly more frequently among those who were positive for TTV DNA by N22 PCR, than among those who were negative by N22 PCR. Twelve patients (32%) were positive for TTV genotype 1. Moderate to marked vacuolation of nuclei, moderate to many acidophilic bodies, and moderate to marked focal/spotty necrosis as well as marked stellate, pericellular or perivenular fibrosis were found significantly more frequently in the TTV genotype 1-positive group than in the TTV genotype 1-negative group. These results suggest that certain TTV genotypes including genotype 1 influence the necrosis and inflammation of hepatocytes and liver fibrosis in NAFLD patients. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.