IgE Sensitization and Identification of IgE Binding Components of the Corn Allergen in Adult Allergy Patients: Comparison between the Wild and the Genetically Modified Corn

Abstract

Background: Recently, genetically modified (GM) food consumption is increasing. Corn is one of the commonly exposed genetically modified foods in Korea. However, there have been no published data to observe the IgE- sensitization rate to GM foods in adult allergy patients in this country. Objective: The aim of this study was to evaluate IgE sensitization and to compare allergenicity of the wild and GM corns in adult allergy patients (>15 years) visited our University hospital. Methods: The 1,716 allergy patients and 40 healthy controls were enrolled. Skin prick tests were performed with the wild and GM corn extracts. Serum specific IgE level to the two kinds of corn extracts was measured by ELISA and their binding specificities were confirmed by ELISA inhibition test. IgE binding components within the two corn extracts were identified using SDS-PAGE followed by IgE-immunoblot. Results: Sixty-four patients (3.7%) showed positive responses (A/H>or=2+) on skin prick test to wild corn and sixty-five patients showed to GM corn. Serum specific IgE was detectable in 66~00% among the positive reactors on skin prick test. ELISA inhibition tests showed significant inhibitions with addition of each corn extracts with similar intensities. IgE-immunoblot analysis demonstrated 21 IgE binding components within the wild corn and 20 IgE binding components within the GM corn with similar binding patterns, in which the 5 major allergenic bands of the each extract were noted in wild (33, 58, 67, 97,104 kDa) and GM corn (33, 58, 83, 97, 104, kDa). Among them, 33, 58, 97 kDa were common and the most frequently bound one (70%) for both corn extracts. Conclusion: The sensitization rates to wild and GM corn extracts were 3.7% and 3.8% in adult allergy patients respectively, and three common major allergens (33, 58, 97 kDa) were identified. Corn can be considered as one of the causative food allergens in this country. Genetic manipulation of the corn could not increase allergenic risk in this country.