Insulin antibody response to bovine insulin therapy: functional significance among insulin requiring young diabetics in India

Abstract

The majority of young diabetics in India prefer to use low-cost bovine insulin for economic reasons. Therefore, the question of insulin antibody response to bovine insulin and its functional significance is still relevant in the Indian context. We assessed insulin antibody response in 52 young diabetics (type 1, n=25, malnutrition modulated form of diabetes, n=19 and fibrocalculous pancreatopathy (FCP) n=8) on bovine insulin therapy (mean duration 3.0± 2.1 years) using an internationally standardised in-house radioligand assay. The functional significance of insulin antibody was assessed by calculating their affinity constant, maximum binding capacity and total insulin binding power by Scatchard analysis (type 1, n=14, malnutrition modulated form of diabetes, n=11). All the patients treated with bovine insulin showed high titers of insulin antibodies with S.D. score ranging from 5.1 to 42.0. No significant difference was observed in the mean S.D. score of insulin antibodies in the three diabetic groups. The mean daily insulin dose, maximum insulin binding capacity and total insulin binding power were significantly higher in type 1 when compared to the malnutrition modulated form of diabetes (36± 8 vs. 26± 11 IU/day, P< 0.05; 9.7± 7.8 vs. 4.0±3.9 nmol/l, P=0.03 and 59± 29 vs. 29± 43, P=0.01, respectively). Insulin antibodies S.D. score and its affinity did not show significant relationship with daily insulin dose and glycemic control (HbAl) at admission. Only 24± 7% variations in daily insulin requirement were accounted for by total insulin binding power. There was a significant inverse relationship between insulin antibody S.D. score and duration of insulin therapy (r=-0.4172, P< 0.0004). To conclude, insulin antibody response following bovine insulin therapy is not different among type 1, malnutrition modulated form of diabetes and FCP diabetes. The insulin antibody response to bovine insulin therapy does not contribute significantly to increase in daily insulin requirement in bovine insulin treated insulin requiring young diabetics.