Definition:
An antibody is a type of protein in the immune system that attacks a specific foreign substance. When your body begins producing antibodies that attack its own tissues, they're called "autoantibodies."
Research suggests that people with chronic fatigue syndrome may have autoantibodies in their blood, but evidence isn't yet strong enough to classify it as an autoimmune disease. Some researchers theorize that chronic fatigue syndrome is caused by an abnormal and possibly chronic immune response.
