Overlap syndrome

Overlap syndromes (OS) between primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC) and autoimmune hepatitis (AIH) represent rare forms of PBC, PSC and AIH, which are characterized by the presence of features of two diseases, typically PBC and AIH or PSC and AIH in the same patient. The diagnosis of OS is based on the presence or sequential development of biochemical, serological, histologic and cholangiographic features of the two diseases. Paris criteria are the recommended criteria for the diagnosis of PBC-AIH OS, whereas no strict diagnostic criteria have yet been established for the diagnosis of PSC-AIH OS. Liver biopsy is mandatory when an OS is suspected and interface hepatitis is a fundamental component for the diagnosis of OS. Patients with OS may present with one or more associated extrahepatic autoimmune disease. Treatment of OS is empiric and includes ursodeoxycholic acid (UDCA) for the cholestatic component and immunosuppressive agents for the hepatitic component, either simultaneously or sequentially. Immunosuppressive treatment in addition to UDCA is recommended in patients with severe interface hepatitis and deserves consideration in those with moderate interface hepatitis. The dominant clinical feature should be treated first and therapy adjusted according to the response. Relapse after IS agent’s withdrawal is elevated in patients with OS. Graft and patients’ survival after liver transplantation in patients with OS are comparable to that observed in patients transplanted for single autoimmune liver diseases.