AIDS stands for "acquired immunodeficiency syndrome," but this disease is not an autoimmune illness. It is caused by a virus (HIV) that damages the person's immune system. Autoimmune diseases include systematic lupus erythematosus, rheumatoid arthritis, psoriasis, type 1 diabetes, Crohn's disease, and multiple sclerosis.

Antibodies attack the body's tissues, organs, or cells.

Researchers don't know why this is so, but one theory suggests that the hormone estrogen may play a role.

Autoimmune disease can affect any organ in the body. But some diseases attack specific organs. In Crohn's disease, for instance, the area affected is the gut. In multiple sclerosis, the areas affected are the brain and spinal cord.

Lupus is more common among African-American women. Hispanic women also are more likely to develop lupus.

Autoimmune diseases have a variety of causes, although healthcare providers don't yet know them all. Some, such as rheumatic fever, develop after a streptococcal infection. People taking methyldopa for high blood pressure can develop lupus. Stopping the medicine usually stops lupus. Some autoimmune diseases run in families, which suggests that genes play a role.

For many autoimmune diseases, the vague early symptoms and lack of specific diagnostic tests make them difficult to diagnose.

There are currently no cures for these diseases. But some, such as multiple sclerosis and rheumatoid arthritis can go into remission even without treatment. For the most part, though, autoimmune illnesses are chronic, needing lifelong monitoring and care. Medicine can help reduce or stop the damage caused by some of the diseases. Medicine can also help suppress the immune system's response, helping to ease symptoms caused by the disease.