NORMALIZATION OF COMPLEMENT ACTIVATION AND CONSUMPTION IN DIABETIC CHILDREN AND ADOLESCENTS AFTER SWITCH-OVER FROM PORCINE TO SEMISYNTHETIC HUMAN INSULIN

  • 1 July 1988
    • journal article
    • research article
    • Vol. 14  (4) , 415-421
Abstract
As the use of human insulin could possibly modify the immunogenicity of insulin, the present prospective study compares complement evaluation (CH50, C3, C3d/C3, C4) as well as other immunological factors (insulin antibodies, autoantibodies,...), metabolic control (HbA1, lipids,...) and clinical data (insulin dose/kg, number of hypoglycaemic episodes,...), before and after a switch-over from monocomponent porcine insulins (Actrapid MC, Monotard MC) to human semisynthetic insulins (Actrapid HM, Protaphane HM). Forty-six type I diabetic children and adolescents (mean age .+-. SD: 14.3 .+-. 3.8 years) participated in the trial. The duration of diabetes ranged from 1.0 to 16.9 years (mean .+-. SD: 7.3 .+-. 3.7). The study protocol consisted of a 9 month period during which, at monthly intervals, the subjects were assessed clinically and blood samples taken for measurement of biological data. After 3 months, porcine insulins were switched to human insulins. The main results were as follows: 1) The insulin dose/kg was increased after the switch-over (porcine insulin: 0.90 .+-. 0.03 U/kg; human insulin: 0.98 .+-. 0.03 U/kg; p < 0.001). This can perhaps be explained by the different bioavailabilities of Monotard MC and Protaphane HM. 2) The objective degree of metabolic control (HbA1), as well as the HDL-cholesterol level and the apo A1/B ratio, were not statistically different before and after the switch-over 3) IgG insulin antibody binding was not statistically different on transfer from porcine insulin to semisynthetic insulin. 4) Mean level of total IgE and IgE specific insulin antibodies, determined before and after the switch-over, were not different. 5) Autoantibodies and antinuclear factor were unchanged. 6) The prevalence of immune complexes was decreased by half (p < 0.05) after six months on human insulin. 7) The patients treated by porcine insulins had an increased complement activity (CH50) (p < 0.001) and an increased C3 activation (p < 0.001) as compared to controls while mean C4 remained unchanged. Moreover, there was an increased mean value of C3 breakdown product C3d and of the catabolic index C3d/C3 (p < 0.001). After the switch-over to human insulins, CH50, C3 and C3d/C3 ratio decreased to the values observed in the healthy controls. In conclusion, the main feature of this prospective study is the demonstration of an abnormal in vivo complement metabolism in diabetic children and adolescents treated with porcine insulins Actrapid MC and Monotard MC and its correction through the use of semisynthetic human monocomponent insulins Actrapid HM and Protaphane HM.