Overlap Syndromes of Autoimmune Liver Disease

Abstract

Autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) are chronic liver diseases of presumed autoimmune origin. Conditions exhibiting features of two different autoimmune liver diseases are commonly designated overlap syndromes, although there is no current agreement on what constitutes an overlap syndrome or specific diagnostic criteria. Identification of patients with features of overlap syndrome is relevant for management as outcomes may differ from outcomes of patients with diagnosis of classic autoimmune liver diseases and treatment may need to be adjusted. Due to their rarity, no large therapeutic trials are available and treatment of overlap conditions is empirical and based upon extrapolation of data from the primary autoimmune liver diseases. AIH-PBC overlap is the most frequently described overlap syndrome and may be associated with a poor prognosis. This may represent an important and unrecognized cause of resistance to ursodeoxycholic acid (UDCA) in patients with PBC. AIH-PSC overlap is less commonly reported. Prognosis may be better than in patients with PSC alone, however worse than in patients with AIH alone. Further studies are needed for determining diagnosis, natural history and optimal therapeutic strategies of overlap syndromes of autoimmune liver diseases.