Abstract

IgG antibodies (AB) to insulin have been reported to influence insulin requirements and control in patients who have taken insulin for prolonged periods of time. Nineteen pregnant type I diabetic patients (C-peptide < 0.03 pmol/ml) were studied in their fifth week of gestation after the establishment of normoglycemia. Mean age was 27.5 yr and duration of diabetes, 14.2 yr (range: 1–23 yr). IgG AB to beef and pork insulin were measured. IgG AB to insulin were encountered in all diabetic patients (range: 103–6736 μU/ml). None of the nondiabetic pregnant controls in their fifth week of gestation (N = 17) had detectable (>50 μU/ml) AB levels. The antibody titer did not affect the insulin requirement (P > 0.2, NS) or ability to achieve normoglycemia. AB levels were correlated with years of treatment with conventional insulin preparations (r = 0.73; P < 0.001). At 5 wk postmenstruation the mean AB level in the patients with less than 10 yr duration of diabetes (N = 7) was 727 μU/ml and mean insulin requirement was 0.7 U/kg/24 h. In the group of patients with greater than 10 yr duration of diabetes (N = 12) the mean antibody titer was 3716 μU/ml and the insulin requirement was also 0.7 U/kg/24 h. IgG AB to insulin increase with increasing duration of treatment with beef/pork insulin. IgG AB do not affect the insulin requirement or the ability to achieve normoglycemia during early pregnancy.