Pathogenesis of primary biliary cirrhosis: CD95-induced apoptosis at last?

Apoptosis is a basic mechanism involved both in maintaining tissue homeostasis by elimination of senescent or potentially harmful cells and in the regulation of immune responses. If not properly regulated, however, it may lead to serious tissue damage. CD95(Fas/APO-1) is a surface receptor that mediates apoptosis upon oligomerization by its ligand, CD95L. The CD95/CD95L-system is one of the major effectors of cytotoxicity in inflammation with implications for both the prevention and the pathogenesis of autoimmune diseases. In primary biliary cirrhosis (PBC), an autoimmune disease, apoptosis has been repeatedly suspected to be the mechanism leading to progressive destruction of bile ducts. The role of apoptosis and its possible molecular inducers in PBC are discussed.