AUTOANTIBODIES AGAINST SYMPATHETIC-GANGLIA AND EVIDENCE OF CARDIAC SYMPATHETIC DYSINNERVATION IN NEWLY-DIAGNOSED AND LONG-TERM IDDM PATIENTS

To investigate the presence of autoantibodies against sympathetic nerv ous tissue and their correlation with cardiac sympathetic dysinnervati on in insulin-dependent diabetes mellitus (IDDM), 20 newly diagnosed ( age 26 +/- 6 years) and 48 long-term IDDM patients (age 40 +/- 13 year s, duration of diabetes 22 +/- 12 years) without myocardial perfusion abnormalities (normal (TC)-T-99m-methoxyisobutylisonitrile uptake) wer e assessed for myocardial I-123-metaiodobenzylguanidine (I-123-MIBG) u ptake and complement-fixing sympathetic ganglia (CF-SG) autoantibodies . Both groups of patients were also studied for islet cell antibodies (ICA) and ECG-based cardiac autonomic neuropathy Eighty control subjec ts (age 18-49 years) were investigated for CF-SG autoantibodies. Eight newly diagnosed (40%) and 12 longterm (25%) IDDM patients exhibited C F-SG autoantibodies, compared to 4 control subjects (5%;p < 0.01, p < 0.05). In long-term diabetic patients, the reduction of global but not of regional myocardial I-123-MIBG up take correlated with CF-SG autoa ntibodies (r = 0.34, p = 0.02). Newly diagnosed diabetic patients did not show an association between CF-SG autoantibodies and global or reg ional myocardial I-123-MIBG uptake. ECG-based cardiac autonomic neurop athy (greater than or equal to two of five cardiac reflex tests abnorm al) was present in 22 and absent in 26 long-term IDDM patients, of who m 9 (41%) and 3 (12%), respectively were positive for CF-SG autoantibo dies (p = 0.02). Only 1 newly diagnosed IDDM patient demonstrated ECG- based cardiac autonomic neuropathy and was also positive for CF-SG aut oantibodies. Although they are somewhat suggestive, results concerning autoantibodies against sympathetic nervous tissue and cardiac sympath etic dysinnervation do not strongly support the view that autoimmune m echanisms play a major role in the pathogenesis of cardiac sympathetic neuropathy in IDDM.