A case of insulin allergy: the crystalline human insulin may mask its antigenicity.
We report an unusual case of insulin allergy. A 48-year-old man with non-insulin-dependent diabetes mellitus receiving biosynthetic isophane human insulin (Humulin N) developed itchy wheal-and-flare reactions at the sites of injection. When Humulin N was changed to a semi-synthetic crystalline human insulin zinc (Novolin U), the allergic reactions completely disappeared. Evaluation of his serum showed a high level of insulin-specific IgE. Skin testing with all commercially available insulins showed immediate local reactions to all agents tested except for Novolin U. In addition, decrystallized Novolin U prepared by lowering the pH with acetic acid also induced a positive reaction. These observations suggest that the crystallized structure of human insulin may mask its antigenicity for allergic reactions.
Takatsuki
H
H
Third Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Ishii
H
H
Yamauchi
T
T
Nakashima
N
N
Nagase
S
S
Hisatomi
A
A
Umeda
F
F
Nawata
H
H
D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D004342:Drug Hypersensitivity; D006801:Humans; D007073:Immunoglobulin E / Q000032:analysis; D007328:Insulin / Q000009:adverse effects* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D012882:Skin Tests
D007328:Insulin; D007073:Immunoglobulin E