Abstract
There is increasing evidence to suggest that insulin-dependent diabetes mellitus is connected with autoimmunity. Antibodies to pancreatic islet cells were detected by indirect immunofluorescence in highest prevalence in insulin-dependent diabetics. That this antibody was complement fixing and of the IgG class has been reported by Bottazzo and Lendrum. The 125I-C1q binding test for detecting soluble immune complexes in native unheated human serum has been modified by Zubler. This radiolabeled C1q binding test has high sensitivity and reproducibility among the various methods proposed for detecting immune complexes.
The method was applied to the study of sera from 52 child patients (3-15 yr old) with insulin-dependent diabetes mellitus.
The 125I-C1q binding activity (C1q BA) for the 52 sera, 9.47±2.58%, was significantly higher than the value of 6.94±2.57% for normal controls (p<0.005). Slightly higher values were seen in 3 patients with positive anti-DNA-antibodies.
125I-C1q binding was not significantly increased in patients with positive antithyroid antibodies and insulin antibodies.
