autoantibody /ô′tō·an″tibod′ē/ [Gk, autos + anti, against; AS, bodig, body] , an immunoglobulin produced by a person that recognizes an antigen on that person’s own tissues. Several mechanisms may trigger the production of autoantibodies: an antigen, formed during fetal development and then sequestered, may be released as a result of infection, chemical exposure, or trauma, as occurs in autoimmune thyroiditis, sympathetic uveitis, and aspermia; there may be disorders of immune regulatory or surveillance function; antibodies produced against certain streptococcal antigens during infection may cross-react with myocardial tissue, causing rheumatic heart disease, or with glomerular basement membrane, causing glomerulonephritis; and normal body proteins may be converted to autoantigens by chemicals, infectious organisms, or therapeutic drugs. Some examples of autoantibodies are those found against gastric parietal cells in pernicious anemia, against platelets in autoimmune thrombocytopenia, and against antigens on the surface of erythrocytes in autoimmune hemolytic anemia. There is growing evidence that genetic factors increase the incidence and severity of autoimmune diseases.
