Diagnosis of sesame allergy: analysis of current practice and exploration of sesame component Ses i 1 (2S albumin)

Abstract Background Sesame is an allergen of increasing importance. Objective We sought to characterize the outcomes of oral food challenges (OFCs) to sesame and evaluate the diagnostic accuracy of skin prick testing (SPT), sesame and Ses i 1-specific IgE (sIgE). Methods We reviewed sesame OFCs performed at the Mount Sinai pediatric allergy clinic between January 2010 and April 2018. We assessed the accuracy of diagnostic tests by calculating the area under the curve (AUC) of the receiver operating characteristic (ROC) curves. Association between OFC outcome and sesame sensitization was analyzed using a logistic regression, which was then used to estimate the 95% positive predictive value (PPV) of these tests. Results We identified 341 patients (69% male, mean age 7.7 years) who underwent sesame OFC. Among 106 (31%) positive OFCs, the median cumulative eliciting dose was 500 mg sesame protein (½ teaspoon tahini). Sesame SPT wheal > 6 mm had sensitivity 54.1% and specificity 87.8%; AUC 0.756 [95% CI 0.699 to 0.814]. SPT wheal size > 14 mm had 95% PPV. Sesame-sIgE level did not correlate with OFC outcome. Ses i - sIgE levels were analyzed in 30 patients using ISAC microarray and were significantly associated with OFC outcome (AUC: 0.715 [95% CI 0.541 to 0.890]). Ses i 1-sIgE > 0.3 ISU had sensitivity 58.3% and specificity 83.3%. Conclusions This is the largest study of sesame allergy to date. Sesame SPT is a more accurate predictor of sesame allergy compared to sesame sIgE. Ses i 1-sIgE appears promising but requires further study regarding diagnostic accuracy.