Overlap Syndrome with Autoimmune Hepatitis and Primary Sclerosing Cholangitis

Abstract

Patients with autoimmune liver disease frequently fit diagnostic criteria for more than one condition. Up to 12.5% of autoimmune hepatitis (AIH) and primary sclerosing cholangitis (PSC) cohorts have a label of AIH/PSC overlap. There can be an interval of many years between the diagnoses of the two conditions, and the sequence in which they are made is unpredictable. Issues exist with the use of diagnostic criteria validated for AIH in patients with AIH/PSC overlap. There are no agreed criteria for the diagnosis of AIH/PSC overlap, it is based on a combination of biochemistry, autoantibody profile, cholangiogram, and liver histology. A positive diagnosis of AIH/PSC overlap impacts therapeutic options and prognosis. There is a beneficial role for immunosuppression, albeit with a higher relapse rate and evidence of progressive liver disease despite immunosuppression in some cases. Liver related outcomes sit somewhere between the constituent diseases, with better outcomes than PSC but poorer outcomes than AIH. There is an increasing body of data for patients with AIH/PSC overlap undergoing liver transplantation for end-stage disease. Nearly half of patients with autoantibody positive liver disease in childhood have autoimmune sclerosing cholangitis (ASC). ASC patients are differentiated from those with AIH by having abnormal cholangiograms. Histological analysis shows chronic hepatitis in <50% of ASC cases. The biochemical response to immunosuppression in ASC patients is less than that seen in AIH patients, and cholangiograms commonly show progressive disease. Transplant-free survival of the ASC population is poorer than in AIH.