[Expression of Fas and Fas-ligand in epithelium of ulcerative colitis].

Ulcerative colitis (UC) is characterized by the loss of epithelium and inflammation of lamina propria. In normal colon, epithelial cells are eliminated by apoptosis at the luminal surface. The apoptotic cells recognized by their typical morphology and the presence of DNA breaks are also accompanied by Fas and Fas-ligand. It is thought when Fas-ligand bound the Fas, the cells bearing Fas will enter a path of apoptosis. On the other hand, in inflamed areas of UC and adjacent un-inflamed areas, the apoptosis of epithelial cells are recognized anywhere along crypts. These findings suggest that unscheduled apoptosis in the UC crypts takes place and the apoptosis is mediated by a auto- or paracrine Fas/Fas-ligand interaction.