Immunogenicity of highly purified bovine insulin: a comparison with conventional bovine and highly purified human insulins.
Twenty-six Type 1 diabetic patients previously treated for 10-20 months with twice daily conventional bovine isophane insulin (containing at least 1000 ppm proinsulin) were changed to highly purified (less than 1 ppm proinsulin) bovine isophane for 6 months (Switch group). Insulin antibody levels fell significantly from a geometric mean of 14.9 to 9.1 micrograms/l. Thirty-two patients with newly diagnosed Type 1 diabetes were treated with the same highly purified bovine isophane insulin twice daily for 6 months (Starter group). Their insulin antibody levels rose from a geometric mean of 1.9 to 8.2 micrograms/l in contrast to values of 1.4 rising to 16.3 micrograms/l in an age and sex matched historical control group treated from diagnosis only with twice daily conventional bovine isophane insulin. Lipoatrophy at injection sites developed in three (9%) in the Starter group treated with highly purified bovine isophane compared to 7 (22%) of those on conventional bovine isophane. Insulin dose and diabetic control did not differ between the groups. Starter and Switch groups were subsequently treated with semi-synthetic human isophane insulin for 6 months during which insulin antibody levels fell significantly from a geometric mean of 8.5 to 4.4 micrograms/l (p less than 0.001). We conclude that bovine insulin purified to less than 1 ppm proinsulin is significantly less immunogenic than its conventional proinsulin contaminated counterpart but even at this level of purity is still more immunogenic than human insulin of equivalent purity.
D000818:Animals; D000936:Antigen-Antibody Complex; D002417:Cattle; D003922:Diabetes Mellitus, Type 1 / Q000188:drug therapy / Q000276:immunology*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007074:Immunoglobulin G; D007328:Insulin / Q000008:administration & dosage / Q000627:therapeutic use*; D007330:Insulin Antibodies / Q000032:analysis*; D011384:Proinsulin / Q000008:administration & dosage / Q000276:immunology
D000936:Antigen-Antibody Complex; D007074:Immunoglobulin G; D007328:Insulin; D007330:Insulin Antibodies; D011384:Proinsulin