Autoimmune hepatitis (AIH) has been found to be heterogenous with respect to clinical features and type of antibodies produced. Three different variants of AIH have been described. The classic form is type I. All types do share many clinical features such as a female preponderance, hypergammaglobulinemia, positive autoantibodies, and their response to corticosteroids. The cause of AIH is not exactly known; however, an abnormal immune response is thought to play a major role.  Type I AIH, which has also been known as lupoid hepatitis, can occur at any age.

The usual presentation is with jaundice, fatigue, and hepatosplenomegaly. As the disease progresses, there is a marked increase noted in the AST and ALT often with concomitant encephalopathy and coagulopathy (usually a prolonged prothrombin time). There are other additional extrahepatic manifestations of AIH. Diabetes type I, arthritis, thyroiditis, vitiligo, cushingoid appearance, abdominal striae, sicca syndrome, and menstrual abnormalities have all been described with type I AIH. Other manifestations can include glomerulonephritis, pulmonary fibrosis, pulmonary hypertension, renal tubular acidosis, autoimmune hemolytic anemia, and idiopathic thrombocytopenic purpura.

Common laboratory findings are hypergammaglobulinemia, and an elevated erythrocyte sedimentation rate. Additional markers include antinuclear antibodies (ANA) found in 50 to 70%, positive antimitochondrial antibodies (AMA) found in 20%, and positive anti-smooth muscle antibodies (SMA) found in 60 to 70% of AIH patients. Type 1 disease is associated with anti-soluble liver antigen/liver-pancreas antibody (found in 10-30% of type 1 disease), whereas type 2 disease is identified by the presence of anti-liver-kidney microsomal-1 antibodies and/or anti-liver cytosol-1 antibodies. Type 2 disease often presents in childhood with a strong predilection for female patients (95% percent of patients). In patients with AIH 10 to 20% will have positive LE cells. These are considered markers of disease activity and do not suggest an alternate diagnosis.

Treatment with corticosteroids with and without the concomitant use of azathioprine has induced clinical and histopathologic remission and has reduced mortality. Relapses are common after discontinuation of therapy.  Orthotopic liver transplantation is necessary in refractory cases.