Autoimmune hepatitis

Abstract

Autoantibodies are detectable in a number of chronic and transient liver dieseases, which include viral hepatitis C and D, drug-induced hepatitis, the autoimmune polyglandular syndrome type 1 (APS-1), as well as genuine autoimmune diseases of the liver (autoimmune hepatitis, primary biliary cirrhosis, primary sclerosing cholangitis). However, autoantibodies alone do not establish the diagnosis of autoimmune hepatitis (AIH), which is reached by the consequent exclusion of other causes of chronic hepatitis. AIH is a chronic inflammatory liver disease affecting women in 80-90% of cases, with an immunological loss of tolerance towards hepatocytes, leading to tissue destruction, liver cirrhosis and liver failure. Autoantibodies and hypergammaglobulinemia are important diagnostic clues. Serology is heterogeneous and includes antibodies against cell nuclei (ANA), smooth muscle actin (SMA), microsomes (LKM) and soluble liver antigen (SLA/LP). The natural history of active AIH is characterized by rapid progression of fibrosis. Under immunosuppressive therapy remission rates are as high as 90% leading to survival rates of 90% in 10 years which makes AIH one of the best treatable chronic liver diseases. In Europe only 4% of all patients with cirrhosis are therefore transplanted with the diagnosis AIH, which becomes necessary when uncontrollable recurrence or primary treatment failures are present. Acute AIH is rare but does occur primarily in children. AIH is frequently associated with clinical signs of extrahepatic immune mediated syndromes which include arthropathy, autoimmune thyroid disease, ulcerative colitis but also amenorrhea and acne, which can precede the development of hepatitis. AIH accounts for up to 20% of cases with chronic hepatitis and is believed to have an incidence of 50-200 cases per million. It is therefore an important differential diagnosis with a favorable prognosis under therapy. © 2006 Dustri-Verlag Dr. Karl Feistle.