title: A case of insulin allergy: the crystalline human insulin may mask its antigenicity.
abstract: 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.
authors.affiliation: Third Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Takatsuki
authors.forename: H
authors.initials: H
authors.lastname: Ishii
authors.forename: T
authors.initials: T
authors.lastname: Yamauchi
authors.forename: N
authors.initials: N
authors.lastname: Nakashima
authors.forename: S
authors.initials: S
authors.lastname: Nagase
authors.forename: A
authors.initials: A
authors.lastname: Hisatomi
authors.forename: F
authors.initials: F
authors.lastname: Umeda
authors.forename: H
authors.initials: H
authors.lastname: Nawata
mesh_terms: 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
chemical_list: D007328:Insulin; D007073:Immunoglobulin E