Juvenile autoimmune hepatitis: A comprehensive review

Autoimmune hepatitis (AIH) is a rare, chronic disease that affects both adults and children, including infants. The disease is probably triggered by environmental factors in genetically predisposed individuals. The clinical presentation ranges from asymptomatic patients or patients with non-specific symptoms, such as fatigue, to fulminant liver failure, many children presenting with symptoms indistinguishable from those of acute hepatitis. Raised transaminase and immunoglobulin G (IgG) levels, in association with circulating autoantibodies, guide towards the diagnosis. The histological hallmark is interface hepatitis, which however is non-specific and may be absent. There are no bile duct changes on cholangiography. Presence of anti-nuclear antibody (ANA) and/or anti-smooth muscle antibody (SMA) is characteristic for type 1 AIH, whereas presence of anti-liver kidney microsomal type 1 (LKM1) antibody and/or anti-liver cytosol type 1 (LC1) antibody defines type 2 AIH. The latter accounts for about one third of the juvenile AIH cases, presents more acutely than type 1 AIH and is very rare in adults. Immunosuppressive therapy, based on steroids and azathioprine, is required, and in the vast majority of patients leads to clinical and biochemical remission, defined as absence of symptoms, normal transaminase and IgG levels, and negative or low-titer autoantibodies. In patients intolerant or non-responder to standard therapy, a number of second line drugs have been employed with variable results. For the rare cases who progress to end stage liver disease, liver transplantation is life-saving, but recurrence of the disease is possible. A better understanding of the underlying pathogenic mechanisms will help to develop new, more effective and less toxic therapies, and to tailor treatment regimens to the individual patient.