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

The sera of 38 patients with nonalcoholic fatty liver disease (NAFLD) inclu ding nonalcoholic steatohepatitis (NASH), were tested for TT virus (TTV) DN A by polymerase chain reaction (PCR) using three different primer pairs (UT R PCR, N22 PCR and genotype-l PCR), and various histological features of th e liver biopsy specimens were compared among those who were positive or neg ative for TTV infection. By UTR PCR which detects all TTV genotypes, TTV DN A was detected in 37 (97%) of the 38 patients. In contrast, N22 PCR which d etects primarily TTV genotypes 1-4, detected TTV DNA in 18 patients (47%). In the liver biopsy specimens, moderate to many acidophilic bodies, moderat e to marked focal/ spotty necrosis of hepatocytes and marked stellate, peri cellular or perivenular fibrosis were observed significantly more frequentl y among those who were positive for TTV DNA by N22 PCR, than among those wh o were negative by N22 PCR. Twelve patients (32%) were positive for TTV gen otype 1. Moderate to marked vacuolation of nuclei, moderate to many acidoph ilic bodies, and moderate to marked focal/spotty necrosis as well as marked stellate, pericellular or perivenular fibrosis were found significantly mo re frequently in the TTV genotype 1-positive group than in the TTV genotype 1-negative group. These results suggest that certain TTV genotypes includi ng genotype 1 influence the necrosis and inflammation of hepatocytes and li ver fibrosis in NAFLD patients. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.