Interpretation

Elevated levels of IgA can occur with mucosal inflammation (pneumonia, colitis, gastritis), autoimmune or liver disease. This particular class of antibody is often associated with the phenomenon of beta-gamma bridging sometimes seen on serum protein electrophoresis. IgA deficiency is the most common immunoglobulin to be deficient. Estimates of the incidence of IgA deficiency range from 1 in 700 to 1 in 500 people. Decreased levels of IgA is associated with chronic respiratory infections, allergies, autoimmune phenomena, and an increased risk for neoplasm. Deficient and rarely absent serum IgA globulin occurs in some clinically asymptomatic individuals. In addition, IgA deficiency can be associated with complex immunodeficiency syndromes (chronic mucocutaneous candidiasis, ataxia telangiectasia, Nezelof syndrome) as well as IgG subclass deficiencies. Some children with IgA deficiency become normal over a period of several years. Transfusion reactions of the anaphylactoid type are disturbingly common with IgA deficiency. This can be a significant problem since many IgA deficient individuals are asymptomatic. See Additional Information below.