An autoantibody is an immune protein that is directed against the body. Under normal conditions, antibodies are produced by the immune system as protection against something perceived as foreign to the self, such as an invading pathogen or an aberrant cell. These antibodies effectively recognize and destroy these foreign invaders to ensure health. In contrast to these normally functioning antibodies, an autoantibody perceives the body’s own proteins or tissues as foreign or as pathogens, and works to damage or destroy them.
Autoimmune diseases refer to a variety of conditions caused by the presence of an autoantibody. Some of these disorders can be very specific and targeted against a single gland or organ, such as Graves’ disease in which an autoantibody, or multiple autoantibodies, are produced against the thyroid gland. Other autoimmune diseases may be more widespread, such as lupus erythematosus, in which the immune system attacks multiple parts of the body, including the kidneys, blood, and heart. Rheumatoid arthritis is another disease caused by autoantibodies, resulting in inflammation of the joints.
It is still not known why some people produce these autoantibodies and develop autoimmune disorders. Although there appears to be a genetic link because some of these disorders tend to occur on a multiple basis within families, most doctors and researchers agree that a genetic basis does not entirely explain the incidence of these disorders. Instead, it is thought that there is an underlying genetic predisposition to autoimmune diseases, but there is usually some kind of triggering event in the environment, such as a viral infection or toxin exposure. In addition, most of these diseases are more common in women and are most likely to occur during childbearing years, so there is probably also a hormonal component.
One characteristic of many autoimmune diseases is that the symptoms tend to be cyclic, and in some cases they can disappear for years only to suddenly flare up again when least expected. This suggests that the body can turn the production of autoantibodies on and off, but how or why the body does this is not fully understood. An understanding of this process may result in effective treatments for disorders that result from autoantibody production. Until it is better understood how to shut off the body’s production of autoantibodies, however, autoimmune diseases can usually be treated best with drugs that suppress the immune system, or immunosuppressant drugs.