Autoimmune hepatitis in children.

Autoimmune hepatitis (AIH) remains an enigmatic condition that affects children of all ages. Although much knowledge has emerged over the past four decades regarding autoimmune diseases, the lack of a spontaneous animal model has hindered a more complete understanding of the pathophysiology of AIH. Serum autoimmune markers, combined with biochemical and histologic evidence of hepatocellular injury and absent other diagnostic considerations, are necessary to diagnose AIH. The clinical spectrum ranges from asymptomatic elevation of aminotransferase levels to acute liver failure. Patients with AIH type 1 are more likely to be older and have cirrhosis at the time of diagnosis, whereas those with AIH type 2 may have a more fulminant course and require life-long immunosuppressant medications. Overlap syndromes occur in children but are rare. Treatment with prednisone and azathioprine, alone or in combination, reverses the clinical course and improves biochemical abnormalities. Should liver transplantation be necessary, autoimmune injury may recur in the allograft.