DEPOSITION OF C3, THE TERMINAL COMPLEMENT COMPLEX AND VITRONECTIN IN PRIMARY BILIARY-CIRRHOSIS AND PRIMARY SCLEROSING CHOLANGITIS

Characteristics of primary biliary cirrhosis (PBC) and primary scleros ing cholangitis (PSC) are bile duct destruction and portal inflammatio n. Increased levels of circulating complement activation products are also present. This raises the possibility of involvement of complement -dependent cytotoxic mechanisms in the pathogenesis. Therefore, we inv estigated liver biopsy specimens from 21 patients with PBC, six patien ts with PSC and six controls for complement deposits by immunohistoche mistry using polyclonal and monoclonal antibodies against C3d, the ter minal complement complex (TCC) and vitronectin (S-protein). We found C 3d, TCC and vitronectin deposits only in the portal tracts. C3d and TC C were present in the walls of the hepatic arteries and in the connect ive tissue stroma but never around the bile ducts. We found vitronecti n deposits throughout the connective tissue, often independent of the TCC deposits. When vitronectin and TCC were co-localized, the staining patterns were inverse: that is, intense staining for TCC accompanied weak staining for vitronectin and vice versa. Occasionally complete di ssociation between TCC and vitronectin staining was observed. Deposits of TCC and vitronectin showed a focal distribution leaving many porta l tracts free of TCC. Our results question whether complement-dependen t cytotoxic mechanisms take part in the bile duct destruction in PBC a nd PSC.