Measurement Specific IgE against Recombinant 16-kD and 19-kD Buckwheat Allergens for the Diagnosis of Buckwheat Allergy

Abstract

Background: Buckwheat (BW, Fagopyrum esculentum)-specific IgE (sIgE) measurement is crucial to diagnose BW allergy. However, clinical application is difficult due to a high false-positive rate. Previously we identified 16-kD 2S storage albumin and 19-kD vicilin-like protein as BW major allergens. Objective: To investigate clinical usefulness of sIgE measurements against recombinant 16- and 19-kD BW allergens compared to the skin prick test and measurement of specific IgE against whole buckwheat (WBW) extract. Method: Eleven BW allergic patients, 11 asymptomatic sensitizers to BW and 16 non-atopic subjects were enrolled. We performed the skin prick test, sIgE measurement against recombinant 16- and 19-kD BW allergens and WBW extract using a CAP system. Result: In BW allergic patients, sIgE against WBW extract, r16- and r19-kD BW allergens were detected in 10, 5 and 9 patients, respectively. In asymptomatic sensitizers, sIgE against WBW extract, r16- and r19-kD BW allergens were detected in 9, 1 and 2 patients respectively. In ROC analysis, the AUC value of sIgE level was higher in r19-kD allergen than in r16-kD or WBW extract. Conclusion: We suggest that CAP sIgE against r19-kD and r16-kD BW allergens can be a diagnostic marker to discriminate BW allergic patients from asymptomatic sensitizers in a clinical setting.