Proinsulin and A-component antibodies in diabetics after long-term monocomponent insulin treatment.

In newly diagnosed diabetics treated with Monotard (porcine monocomponent (MC) Lente insulin) for five years, no antibodies against porcine or bovine proinsulin were observed, but 2 of 13 subjects developed a-component antibodies. In newly diagnosed diabetics, treatment for the same period with conventional Lente insulin induced both proinsulin and a-component antibodies (in 5 and 8 of 10 cases, respectively). In 31 patients transferred from conventional Lente to Monotard, proinsulin and a-component antibody levels were significantly lower than in 22 patients maintained on conventional Lente after the 5-year follow-up period. No significant differences were noted between bovine and procine proinsulin antibodies. Insulin antibody production was similar to that of proinsulin antibody.