Primary sclerosing cholangitis: Etiology and immunology

Primary sclerosing cholangitis (PSC) is a chronic progressive cholestatic liver disease, the etiology of which remains poorly defined. We have reviewed known abnormalities in both the humoral and cell-mediated immunologic systems and describe the abberant expression of class II HLA antigens on biliary epithelial cells. Further work is needed to unite the known findings into a cogent hypothesis, to explain the association of PSC with ulcerative colitis in some patients, and to guide us in developing effective therapy for this, as yet, untreatable disease.