Autoimmune hepatitis and viral infection.

In summary, type 1 autoimmune hepatitis is infrequently associated with serologic markers of viral infection, and there is no direct evidence that viruses are important causes of this disease. Patients seropositive for anti-LKM1 are commonly infected with HCV, but these patients have predominant features of chronic viral hepatitis and frequently lack antibodies to P450IID6. Such patients respond to therapy with interferon and should be distinguished from patients with type 2 autoimmune hepatitis who have anti-P450IID6, seronegativity for anti-HCV, and responsiveness to corticosteroids. In patients with ANA and/or SMA seropositivity and anti-HCV, a false-positive reaction for anti-HCV must be excluded by recombinant immunoblot assay. Patients with false anti-HCV seropositivity should be treated with corticosteroids. In contrast, patients with a true viral infection and low-titer autoantibodies should be treated with interferon. In patients with true viral infection and high titers of auto-antibodies, the treatment decision must balance the autoimmune and viral manifestations. An empiric trial of corticosteroids is justified if autoimmune features predominate.