AUTOANTIBODIES AGAINST ADRENAL-MEDULLA IN TYPE-1 AND TYPE-2 DIABETES-MELLITUS - NO EVIDENCE FOR AN ASSOCIATION WITH AUTONOMIC NEUROPATHY

Objective. To examine the role of autoimmunity in the development of a utonomic neuropathy in diabetes mellitus. Design. Retrospective cross- sectional study. Setting. The Department of Medicine, University Hospi tal, Uppsala, and the Department of Endocrinology, University of Lund, Malmo General Hospital, Malmo, Sweden. Subjects and main outcome meas ures. We examined 135 patients with type 1 (n = 96) or type 2 (n = 39) diabetes mellitus, Tests for cardiovascular autonomic functions were performed, and patient sera were analysed for the presence of autoanti bodies against the adrenal medulla by indirect immunofluorescence, Wes tern blot and immunoprecipitation techniques. Results. Sera from 13% ( 12/96) of the type 1 and 20% (8/39) of the type 2 patients showed a po sitive cytoplasmic immunofluorescence (IF) staining of the adrenal med ullary cells, as did 20% (30/151) of sera from healthy controls. Fifty -eight and 64% of type 1 and type 2 patients, respectively, had cardio vascular autonomic neuropathy, but no correlation between autonomic ne uropathy and positive IF against the adrenal medulla was observed, wit h the exception of significant drops in diastolic blood pressure 8 min after tilt (P < 0.005) in type 1 patients, The various IF-positive se ra reacted with several different proteins when analysed with Western blot technique using a total homogenate of the bovine adrenal medulla, These did not correspond to any of the proteins involved in the synth esis or storage of catecholamines which were considered as putative au toantigens. Conclusion. The finding of similar frequencies of immunogl obulins binding to adrenal medulla in both type 1 and 2 diabetic patie nts as well as in normal controls, argues against a role of anti-adren omedullary antibodies in the pathogenesis of autonomic diabetic neurop athy.