Abstract
A-component in the crystalline insulin was one of impure substances of higher molecular weight contaminating the conventional insulin solution sold before June, 1975. The blood samples used in this study had been collected before May, 1975.
The presence of specific anti-a-component antibodies was examined in sera of 14 patients who had circulating anti-insulin antibodies possibly produced by autoimmunity, six of them showed insulin autoimmune syndrome with spontaneous hypoglycemia and the remaining 8 patients had only the autoimmune antibodies without hypoglycemic attacks. Sera of 14 diabetics treated with conventional insulin for more than one year were also examined.
Percentages of 125I-a-component bound with sera of all the patients of both groups were higher than normal. However, after preincubation of the sera with cold Monocomponent Insulin, the percentages of 125I-a-component bound with sera of all the patients with insulin autoimmunity entered in the normal range with one exceptional case.
On the contrary, the percentages in patients treated with insulin were still higher than normal.
The serum of one diabetic patient who had been treated with Monocomponent Insulin and developed anti-insulin antibody showed the same pattern of binding with 125I-a-component as the sera of the autoimmune group.
In conclusion, the specific antibody to a-component was found only in sera of the patients treated with conventional insulin. And the detection of anti-a-component antibodies might be one of important methods to differenciate the insulin autoimmune syndrome from factitious hypoglycemia appeared before June, 1975.
