Immunohistochemical Study of Fas in Liver Tissues of Chronic Viral Hepatitis

Nam, Soon Woo; Cho, Sang Wook; Choi, Hwang; Kim, Byung Wook; Kim, Sung Soo; Yang, Jin Mo; Han, Nam Ik; Lee, Chang Don; Cha, Sang Bok; Chung, Kyu Won; Sun, Hee Sik

Abstract

BACKGROUND/AIMS: Fas was proposed as a protein that triggers or mediates apoptosis combining with Fas ligand on cytotoxic T lymphocytes. The mechanism of hepatic injury in chronic viral hepatitis may also include Fas-mediated apoptosis. We evaluated the expression patterns of Fas in liver tissues of patients with chronic viral hepatitis.
METHODS
Eighty-six liver biopsy samples from patients with chronic viral hepatitis (64 HBsAg positive, 22 anti-HCV positive) were immunohistochemically stained for Fas. Histological findings were evaluated according to the Knodell's Histologic Activity Index (HAI).
RESULTS
Incidence of Fas-positive hepatocytes in chronic viral hepatitis was 75.5% (75% in type B and 77.2% in type C). Hepatocellular localization of Fas expression in hepatitis B was the membrane in 89.5% of the patients and the cytoplasm in 87.5% of them. In hepatitis C, it was the membrane in all cases and the cytoplasm in 76.4%. Fas positive hepatocytes were the most frequently detected in periportal area. The prevalence of Fas expression was 100% in chronic active hepatitis of both type B and type C, while in chronic persistent hapatitis, it was 68.8% in type B and 73.3% in type C. There was a positive relationship between the grade of Fas expression and HAI score.
CONCLUSIONS
Hepatocytic apoptosis associated with Fas expression may play a role in the pathological mechanism of the hepatic injury in chronic viral hepatitis.