Complement-fixing antibodies to sympathetic and parasympathetic tissues in IDDM. Autonomic brake index and heart-rate variation.
 We describe herein complement-fixing anti-adrenal medullary (CF-ADM) and anti-sympathetic ganglia (CF-SG) antibodies in insulin-dependent diabetes mellitus (IDDM).
 This study describes complement-fixing anti-vagus (CF-V) nerve antibodies and their relationship to the cardiovascular autonomic brake index (a measure of transient decrease in heart rate during the 1st min after a tilt), and R-R interval variation with deep breathing.
 CF-V was detectable in 7 of 83 (8.4%) subjects with IDDM aged 1.5-65.5 yr (mean +/- SE 28.7 +/- 1.8 yr) and duration of diabetes 0-47 yr (11.8 +/- 1.4 yr).
 Seventy-six nondiabetic subjects (aged 10-65 yr) all had negative CF-V scores.
 CF-V scores correlated with CF-ADM (0-16 yr of IDDM, r = 0.61, P less than 0.0001) and CF-SG (r = 0.39, P less than 0.05).
 Seventy IDDM subjects (aged 28 +/- 5 yr, duration of diabetes 17 +/- 3 yr) without proteinuria or proliferative retinopathy were screened for CF-ADM, CF-SG, and CF-V antibodies.
 Five of 70 (7.1%) had CF-SG only (negative for CF-ADM and CF-V).
 Brake indices ranged from 14.7 to 51.3 (37.3 +/- 6.9).
 Three of 70 (4.2%) had CF-ADM only, with brake indices from 26.9 to 45.1 (32.9 +/- 6.1).
 Four of 70 (5.7%) had CF-V antibodies only, with brake indices of 12.7-17.3 (15.1 +/- 1.1).
 Subjects with CF-SG or CF-ADM (anti-sympathetic) had higher brake indices than subjects with CF-V (anti-parasympathetic) antibodies (P less than 0.03).
