Investigation of TTV by in situ hybridization in patients with chronic hepatitis

To clarify whether TT virus (TTV) was present in liver tissues, 12 liver ti ssue samples from patients with chronic hepatitis positive for TTV in their serum and 11 samples from serum-negative patients were obtained by needle biopsies and investigated using in situ hybridization. Positive staining wa s observed in nine (75%) of 12 cases positive for TTV (serum-positive group ) and three (27.3%) of 11 cases negative for TTV (serum-negative group) (P = 0.061). Three kinds of staining patterns were observed: nuclear, cytoplas mic and both. In 58.3% (7/12) of the patients positive for TTV staining, th e stained areas were found in both the nucleus and cytoplasm. Only cytoplas mic staining was observed in three cases from the serum-positive group. Onl y nuclear staining was observed in two cases from the serum-negative group. No significant differences were found in the clinical background between t he in situ hybridization-positive and -negative groups, and between the ser um-positive and -negative groups. The present study shows that TTV exists i n the liver tissue, especially in hepatocytes, of chronic hepatitis patient s and that the localization of TTV in the cell is different from case to ca se, although why this is sq remains to be clarified. (C) 2000 Elsevier Scie nce Ireland Ltd. All rights reserved.