Clinical application of the different cross-reactivities of anti-insulin antibodies to insulin lispro to evaluate endogenous insulin secretion.

Abstract Background Insulin analogs are often used to treat patients with diabetes. We evaluated the cross-reactivities of anti-insulin antibodies in two insulin immunoassay kits (Architect and ECLusys) against recombinant human insulin and insulin analogs, and measured insulin concentrations in the serum of the diabetic patients treated with only insulin lispro. Methods Ten-fold dilutions of recombinant human insulins and insulin analogs were measured using Architect and ECLusys kits. The serum samples of 4 type 2 diabetic patients at fasting, and several time points after breakfast (25 kcal/kg) following subcutaneous injection of insulin lispro were measured by Architect, ECLusys and LISPro RIA kit. Results The ECLusys kit could detect human insulin but not insulin analogs. The Architect kit detected human insulin and insulin analogs with similar recovery ratios. The difference in serum insulin concentrations measured by Architect and ECLusys assays reflected the concentration measured by LISPro insulin kit in the patients. The differences in the AUC between Architect and ECLusys assays were significantly correlated with the AUC for LISPro assay (p  Conclusions By exploiting the different cross-reactivities of anti-insulin antibodies to insulin analogs, it may be possible to measure the endogenous and exogenous insulin concentrations in diabetic patients treated with insulin analogs.