Factors affecting insulin antibody binding in children with insulin-dependent diabetes mellitus.

We measured insulin antibody binding in 2 groups of patients: Study 1, 32 children with newly diagnosed IDDM before onset of insulin therapy, and, in 20 of these, 10 days, 1, 3, and 6 months after beginning therapy; and Study 2, 35 children with long-standing IDDM, 20 of whom had free insulin concentrations measured before, and for 2 hours following subcutaneous injection of 0.25 U/kg regular insulin. Almost 35% of new onset subjects had insulin antibody binding above control levels. In those studied prospectively, binding increased significantly with time. Pre-treatment binding did not correlate with later insulin antibody binding nor metabolic control. In Study 1 we have confirmed previous studies showing abnormally high insulin antibody binding in children with IDDM pre-treatment. We have been unable to demonstrate a relationship between this binding and that found 6 months after initiation of therapy. In Study 2, we have shown that insulin antibody binding is not related to either the level of metabolic control or the rate of rise of free insulin levels in children with IDDM.