Changes in antigenicity after new administration of semisynthetic human insulin or shifts from conventional insulin

ABSTRACT

The present study was carried out on 44 insulin-dependent diabetic [IDD] patients divided into three groups Group 1 comprised 15 uncontrolled IDD patients transferred from conventional insulin therapy to semisynthetic human insulin [SHI], group 2 comprised 14 IDD patients transferred from porcine monocomponent insulin therapy [PMCI] to SHI and group 3 comprised 15 recently diagnosed IDD patients who were given insulin for the first time in the form of SHI. All patients were followed up after one, three, six and twelve months. The daily insulin dose was not allowed to be increased during the study period, but was decreased whenever needed. Group 1 showed significant decrease in serum insulin antibodies throughout the study. There was also significant reduction in oral glucose tolerance sum, denoting better glycemic control, with a subsequent gradual decrease in insulin daily dose. As regards group 2, there was insignificant change in serum insulin antibody levels as well as glycemic levels throughout the study period. In group 3, there was a gradual increase in serum insulin antibody levels during the study period. This increase, although insignificant in the first month, was significant in the third and sixth months of the study, then became insignificant once more by the end of the 12th month. This suggested the presence of autoantibodies which are formed before the onset of SHI therapy and even before the onset of diabetes. This group showed also significant decrease in glucose tolerance sum [GTSo-2 h] values throughout the study. This was simply attributed to the administration of insulin. These results showed the SHI and highly purified porcine insulin do not differ in respect to immunogenicity as well as efficacy in controlling blood glucose concentration