Selective IgA deficiency and autoimmunity.

Laboratory and clinical data are presented in fifteen patients under the age of sixteen years with selective IgA deficiency, all of whom had normal serum IgG, IgM, IgD and IgE. Results indicate a high incidence of autoimmune disease, autoimmune phenomenon or unusual antibody formation. Three patients had thyroiditis, one cerebral vasculitis, one pulmonary haemosiderosis, one cystic fibrosis and nine had recurrent upper respiratory tract infections. Ten out of fifteen were positive for one or more `autoantibodies.' Selective IgA deficiency cannot always be considered a benign entity and individuals with this defect warrant complete investigation.