Autoimmune hepatitis is usually a chronic form of hepatitis that frequently leads to progressive liver damage. However, in about 10-20% of cases, it may present like acute hepatitis. For reasons that are not fully understood, the body's immune system targets and attacks the liver. It is more common in women than men; in fact, according to the American Liver Foundation, 70% of those affected are female, usually between the ages of 15 and 40.
There are two forms of autoimmune hepatitis. The more common form is type I, which most often affects young women and may be found in association with other autoimmune disorders, such as type 1 diabetes, ulcerative colitis, and Sjogren syndrome. Type II is much less common and has been found to affect mostly girls between the ages of 2 and 14; it is more common in Europe than in the U.S.
Signs and symptoms of autoimmune hepatitis correspond to those of hepatitis in general. See the section on Signs and Symptoms for detailed information.
Several tests for various autoantibodies may be ordered to help diagnose autoimmune hepatitis and to look for other associated autoimmune disorders. The most common of these include:
- Antinuclear antibodies (ANA)
- Anti-smooth muscle antibodies (ASMA) and anti-actin antibodies — the majority of smooth muscle antibodies produced with autoimmune hepatitis is specifically directed against a protein called actin or F-actin. Testing is available for specific actin autoantibodies, but it is not available in every laboratory.
- Antibodies to liver and kidney microsomes (anti-LKM1)
Typically, people who have type I autoimmune hepatitis have ANA, ASMA, or both, and people who have type II have anti-LKM1.
Treatment for autoimmune hepatitis usually involves drugs that suppress the immune system and block the body from producing autoantibodies, limiting the inflammation caused by autoimmune reactions. This includes medications such as prednisone and azathioprine, although these treatments may not be effective in all cases. People who do not respond to these drugs or who develop severe side effects from the medications may be prescribed other immunosuppressive drugs such as mycophenolate mofetil, cyclosporine, or tacrolimus.
Typically, autoimmune hepatitis can be controlled with these medications but cannot be cured. People with this disease must often take these medications for many years and, in some cases, for life. If medication is stopped, the disease may return. These medications do have some side effects associated with their use. People with mild forms of this disease may not be treated with these drugs.
In some people, autoimmune hepatitis progresses to cirrhosis and end-stage liver failure, and a liver transplant may be necessary.