The immunogenicity of insulin preparations

Patients who had never received insulin were administered porcine or bovine Lente insulins prepared from either conventional USP-grade insulin, "single-peak" insulin (SPI), or "single-component" insulin (SCI) in an attempt to determine if insulin immunogenecity was related to the purity of various insulin preparations. Serum insulin antibody titers were monitored by a sensitive I125-insulin binding procedure. All six groups of patients had some degree of antibody formation after six months of continuous insulin administration. Based upon the percent of I125-insulin bound by the serum, the least immunogenic insulin preparation was the porcine SCI. The most immunogenic insulins were the bovine preparations, all three of which gave comparable antibody responses. The patients who received porcine USP insulin and porcine SPI had similar antibody titers, both of which were significantly higher than the titers from the patients on porcine SCI, but significantly lower than the antibody titers from the patients treated with any of the bovine preparations. The immunogenicity of bovine SCI was significantly reduced by administering multiple daily doses of the neutral regular form instead of one or two daily injections of the Lente form, Although these purer insulin preparations (SPI and SCI) are still associated with various degrees of immunogenecity, they are significant improvements for the treatment of insulin lipoatrophy and insulin allergy.