Evaluation of the basophil activation test and skin prick testing for the diagnosis of sesame food allergy

Abstract

Background: The prevalence of sesame food allergy (SFA) has increased over recent years, with the potential of anaphylactic reactions upon exposure. Oral food challenge (OFC) remains the diagnostic standard, yet its implementation may be risky. Commercial skin prick tests (SPT) have a low sensitivity. Investigation of alternate diagnostic methods is warranted. Objective: To evaluate the utility of SPT and the basophil activation test (BAT) for SFA diagnosis. Methods: Eighty-two patients with suspected SFA completed an open OFC to sesame or reported a recent confirmed reaction. Patients were administered skin prick tests (SPT) with commercial sesame seed extract (CSSE) and a high protein concentration sesame extract (HPSE) (100 mg/mL protein). Whole blood from 80 patients was stimulated with sesame seed extract (40-10 000 ng/mL protein) for BAT), assessing CD63 and CD203c as activation markers. Results: Sixty patients (73%) had IgE-mediated reactions to sesame, and 22 (27%) did not react. Receiver operating characteristic (ROC) curve analysis demonstrated an area under the curve (AUC) of 0.87 for HPSE-SPT and 0.66 for CSSE-SPT. At 1000 ng/mL of sesame protein, induction of CD63 and CD203c was weakly but significantly associated with OFC eliciting dose by rank (Spearman's rho = −.42 (P