A form of liver inflammation in which the body's immune system attacks liver cells.
Autoimmunity causes the body's defense mechanisms to turn against itself. Many of the tissues in the body can be the target of such an attack. While one tissue type predominates, others may be involved in a general misdirection of immune activity, perhaps because the specific target antigen is present in differing quantities in each of the affected tissues. There seem to be hereditary causes for autoimmunity, since these diseases tend to run in families and have genetic markers. Among the more common diseases believed to fall within this category are rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, and psoriasis.
The process of autoimmune disease is very similar to infectious disease and allergy, so that great caution is observed in placing a disorder in this class. Germs were found to cause several diseases originally thought to be autoimmune. Allergens cause others. Many more may be uncovered. Autoimmunity is often believed to originate with a virus infection. A chemical in the virus resembles a body chemical so closely that the immune system attacks both.
Autoimmune hepatitis is similiar to viral hepatitis, a disease of the liver. It can be an acute disease that kills over a third of its victims within six months, it can persist for years, or it can return periodically. Some patients develop cirrhosis of the liver which, over time, causes the liver to cease functioning.
Causes and symptoms
Symptoms of autoimmune hepatitis resemble those of other types of hepatitis. Patients who develop autoimmune hepatitis experience pain under the right ribs, fatigue and general discomfort, loss of appetite, nausea, sometimes vomiting and jaundice. In addition, other parts of the body may be involved and contribute their own symptoms.
Extensive laboratory testing may be required to differentiate this disease from viral hepatitis. The distinction may not even be made during the initial episode. There are certain markers of autoimmune disease in the blood that can lead to the correct diagnosis if they are sought. In advanced or chronic cases a liver biopsy may be necessary.
Autoimmune hepatitis is among the few types of hepatitis that can be treated effectively. Since treatment itself introduces problems in at least 20% of patients, it is reserved for the more severe cases. Up to 80% of patients improve with cortisone treatment, although a cure is unlikely. Another drug—azathioprine—is sometimes used concurrently. Treatment continues for over a year and may be restarted during a relapse. At least half the patients relapse at some point, and most will still continue to have progressive liver scarring.
If the liver fails, transplant is the only recourse.
In spite of treatment autoimmune hepatitis can re-erupt at any time, and may continue to damage and scar the liver. The rate of progression varies considerably from patient to patient.
American Liver Foundation. 1425 Pompton Ave., Cedar Grove, NJ 07009. (800) 223-0179. 〈http://www.liverfoundation.org〉.
Allergen— Any chemical that causes an immune reaction only in people sensitive to it.
Antigen— Any chemical that can be the target of an immune response.
Biopsy— Surgical removal of a piece of tissue for examination.
Jaundice— A yellow color to the skin from bile that backs up into the circulation.