THE IMMUNOGENIC PROPERTIES OF HIGHLY PURIFIED INSULIN PREPARATIONS. THE CLINICAL IMPORTANCE OF INSULIN-BINDING ANTIBODIES

ABSTRACT Twenty-four diabetic patients were treated with porcine protamine-insulin (NPH-insulin) containing 7–13 mmol proinsulin per mol insulin and 27 diabetic patients were treated with porcine protamine-insulin (HP-insulin) containing 0.36 mmol proinsulin per mol insulin. 75 % of the patients treated with NPH-insulin and 15 % of the patients treated with HP-insulin formed detectable insulin-binding antibodies. The difference in the antibody titre in the two groups was significant. As a group, patients treated with HP-insulin did not have a significant rise in the plasma insulin-binding capacity when compared to pre-treatment values. When comparing patients with antibodies and patients without detectable antibodies no difference in the degree of regulation could be demonstrated between the two groups. Young patients with antibodies had a higher insulin requirement per kg per day than patients without detectable antibodies. Among patients in remission those without detectable antibodies had a longer remission period than those with antibodies. Apart from the difference in antibody formation and hence a different distribution in the groups compared, the patients treated with NPH-insulin and HP-insulin did not differ with regard to the degree of regulation, the insulin requirement or the duration of the remission period.

INSULIN ANTIBODY FORMATION

ABSTRACT Sixty-three patients with diabetes mellitus were treated with a porcine or a bovine insulin preparation, either in solution or in a crystal suspension of protamine-insulin. The amounts of circulating insulin-binding antibodies were periodically determined for up to 3 years. Forty-nine patients developed antibodies during the first 6 to 9 months of treatment. Taking into account the length of insulin treatment and the age of the patients, the amounts of antibodies developed were compared for groups treated with the different insulin preparations. Of the patients treated with insulin in a neutral solution, those who had received bovine insulin developed significantly more antibodies than those treated with porcine insulin. Patients treated with porcine insulin in a neutral solution developed only traces of antibodies. The mean titre was significantly less than for patients treated with porcine insulin in an acid solution or as protamine-insulin. Treatment with porcine protamine-insulin resulted in significantly less antibody formation, provided the patients had received porcine insulin in a neutral solution before the treatment with protamineinsulin. It was shown that as a rule, patients developed antibodies with the same avidity for porcine and bovine insulin, although a few patients treated with porcine or bovine insulin developed antibodies with greatest avidity for bovine insulin.