Systemic lupus erythematosus is an autoimmune disorder. In a normal immune system, the body releases proteins (antibodies) to fight viruses, toxins and other potentially harmful foreign substances (antigens). With lupus and other autoimmune diseases, the immune system does not work properly. It produces autoantibodies that mistakenly attack and destroy the body’s own healthy cells and tissue. These autoantibodies also trigger inflammation, which can lead to organ damage.
Autoantibodies called antinuclear antibodies (ANA) are detectable in most, although not all, patients with SLE. Tests for the presence of ANA are used as part of the diagnostic work-up for the condition. (For more information, see “ANA Tests” in Diagnosis section of this report.)
Scientists do not know exactly what causes the abnormal immune response associated with autoimmune disorders. It is most likely a combination of genetic and environmental factors. People who develop an autoimmune disease may have a genetic predisposition that is triggered by some environmental factor such as sunlight, stress hormones, or viruses. It does not appear that one gene alone is responsible for lupus. Researchers estimate that 20 - 100 different genetic factors make a person susceptible to SLE.
Review Date: 02/18/2011
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.