Autoantibodies, including antibasement membrane antibody, in patients with selective IgA deficiency

Laboratory data are presented on 48 patients with selective IgA deficiency. Sixty percent of the patients had autoimmune diseases or related disorders. We found antibasement membrane antibody (ABMA) in the sera of four IgA deficient patients and the incidence of ABMA seemed to be related to clinical symptoms. The incidence of various other antibodies was found to be increased in selective IgA deficiency. This phenomenon might be derived from the lack of local immune system. Inadequate IgA barrier might permit the exessive gastrointestinal absorption of food antigens or autoimmunogens in metabolic products which are excreted into the gut lumen.