Overlap of autoimmune hepatitis and primary sclerosing cholangitis: an evaluation of a modified scoring system

Background/Aim: Recently, the scoring system for the diagnosis of autoimmune hepatitis (AIH) was modified by the International AIH Group. Our aim was to determine the prevalence of AIH in patients with cholangiographically proven primary sclerosing cholangitis (PSC) using this new scoring system. Methods: A total of 211 PSC patients were evaluated. Results: Three (1.4%) patients scored more than 15 points ('definite' AIH); 13 (6%) patients scored between 10 and 15 points ('probable' AIH); the remaining 195 (93%) patients had less than 10 points, allowing the exclusion of AIH. The separation of patients with PSC plus AIH from patients with PSC alone was based mostly on serum levels of total globulins (p=0.01), IgG (p=0.001), titers of autoantibodies (p<0.001) and histologic score (p<0.001). Using the older scoring system, four (2%) patients met the criteria for the diagnosis of PSC plus 'definite' AIH and 40 (19%) the diagnosis of PSC plus 'probable' AIH. Conclusions: Overlap of PSC and AIH occurs rarely. The new scoring system seems to more precisely define the potential overlap syndrome between PSC and AIH, although further modification of the new scoring system may provide even better discrimination among these conditions.