Autoimmune hepatitis.

Autoimmune hepatitis is characterized by inflammatory liver histology, circulating nonorgan-specific autoantibodies, and increased levels of immunoglobulin G, in the absence of a known etiology. Two types of juvenile autoimmune hepatitis (AIH) are recognized according to seropositivity for smooth muscle and/or anti-nuclear antibody (AIH type 1) or liver kidney microsomal antibody (AIH type 2). There is a female predominance in both. AIH type 2 presents more acutely, at a younger age and commonly with immunoglobulin A deficiency, whereas duration of symptoms before diagnosis, clinical signs, family history of autoimmunity, presence of associated autoimmune disorders, response to treatment, and long-term prognosis are similar in the 2 groups. Immunosuppressive treatment with steroids and azathioprine, which should be instituted promptly to avoid progression to cirrhosis, induces remission in 80% of cases. Relapses are common, often due to nonadherence. Drugs effective in refractory cases include cyclosporine and mycophenolate mofetil. Long-term treatment is usually required, with only some 20% of AIH type 1 patients able to discontinue therapy successfully. In childhood, sclerosing cholangitis with strong autoimmune features, including interface hepatitis and serological features identical to AIH type 1, is as prevalent as AIH, but it affects boys and girls equally. Differential diagnosis relies on cholangiographic studies. In autoimmune sclerosing cholangitis liver parenchymal damage responds satisfactorily to immunosuppressive treatment, whereas bile duct disease tends to progress. In this article we review the state of the art of diagnosis, monitoring, and treatment for children with AIH.