Definition of Autoantibody

An autoantibody is an antibody that reacts against the patient's own body. Normally antibodies attack foreign invaders (antigens). There are several mechanisms that may lead to the making of autoantibodies. For example, antibodies made against certain streptococcal bacteria during infection may react with heart tissue. This causes rheumatic heart disease. Another mechanism is that normal body proteins may be changed to antigens by chemicals, infection, or drugs.


 

Further definition of autoantibody

One or more autoantibodies may be produced by a person’s immune system when it fails to distinguish between “self” and “non-self" proteins. Usually the immune system is able to discriminate by recognizing foreign substances (“non-self”) and ignoring the body’s own cells ("self"), yet not overreact to non-threatening substances such as foods, dust and pollen, or beneficial microorganisms. It creates antibodies only when it perceives what it has been exposed to as a threat ("non-self"). When the immune system ceases to recognize one or more of the body’s normal constituents as “self”, it may produce autoantibodies that attack its own cells, tissues, and/or organs, causing inflammation and damage. The causes of this inappropriate action are varied and are not well understood, often resulting in a chronic autoimmune disorder.