Autoimmune hepatitis

Autoimmune hepatitis (AIH) is a cause of hepatitis which presents acutely but becomes chronic, possibly progressing to cirrhosis.

AIH mostly affects females. It can present at any age but mostly begins in the teens or in elderly. As with most autoimmune diseases, there is associated with other autoimmune diseases.

It has a good response to therapy and a good prognosis, but a 40% mortality rate if untreated. 70% of patients relapse at some point after having reached remission.

Etiology

The development of AIH often involves an environmental trigger (viral infection, drug, etc.) in a genetically susceptible person. The following alleles are associated with AIH:

• HLA-B8
• HLA-DR3
• HLA-DR4

Clinical features

AIH may present asymptomatically (only abnormal laboratory parameters), as acute hepatitis, or with cirrhosis.

Some extrahepatic manifestations of AIH include:

• Vitiligo
• Acne
• Vasculitis
• Erythema nodosum
• Rheumatological disease

Diagnosis and evaluation

As with any hepatitis, liver enzymes (AST, ALT, GGT, ALP) are elevated. AST and ALT may be significantly elevated, often >10x the upper limit of normal. However, the following findings are typical for AIH:

• Autoantibodies
  • Anti-nuclear antibody (ANA)
  • Anti-smooth muscle antibody (SMA)
• Hypergammaglobulinaemia

Biopsy and histology are obligatory to confirm the diagnosis, to determine the activity and stage, and to exclude other diseases. Typical for AIH is lymphocytic infiltration in the portal tract.

Treatment

Immunosuppressive therapy to induce and maintain remission is indicated, in all but very mild cases. Remission is induced with corticosteroids ± azathioprine and maintained with azathioprine or other immunosuppressants. Once remission has been maintained for a long time (>18 months), drug withdrawal may be attempted as many don’t require long-term immunosuppressive therapy to prevent relapse.

In very severe cases, liver transplantation is an option.