Antigen presenting cells in liver biopsies from patients with primary biliary cirrhosis.

Although Langerhans, interdigitating and follicular dendritic cells have been occasionally identified in pathological human liver by ultrastructural morphology, no data are available on their phenotypical their phenotypical identification using monoclonal antibodies. Frozen normal liver samples and biopsies from patients with primary biliary cirrhosis, primary sclerosing cholangitis and chronic active hepatitis were studied using a panel of 12 monoclonal antibodies (including anti class II antigens, follicular dendritic, macrophage and Langerhans cells). In normal liver, class II positive cells were represented by Kupffer and portal tract histiocytes with a macrophage phenotype. In pathological portal tracts non lymphocytic class II positive cells were represented by macrophages, clusters of follicular dendritic cells (which were detected in close association with B cell aggregates), and by sparse Langerhans cells (localized in areas of piecemeal necrosis and in a periductal position or infiltrating class II positive bile ducts). The present data suggest that both classical antigen presenting cells and class II positive bile duct cells may play some role in the induction of autoimmune reactions.