660 - Enhancing the Diagnostic Accuracy of the EXiLE Method for Walnut Allergy

Publication Number: 660.1808

Hikaru Sugita, Fujita Health University, Toyoake city, Aichi, Japan; Yuji Mori, Fujita Health University Bantane Hospital, Nagoya, Aichi, Japan; Yasuto Kondo, Department of Pediatrics, Fujita Health University, School of Medicine, NAGOYA, Aichi, Japan; Tetsushi Yoshikawa, Fujita Health University School of Medicine, Toyoake, Aichi, Japan

Background: Walnut (Juglans regia) frequently triggers nut allergies in the United Kingdom and the United States, with increasing cases in Japan. While oral food challenges are the definitive method for diagnosing these allergies, they pose the risk of symptom provocation, necessitating safer alternative tests.

Objective: We aimed to evaluate the diagnostic utility of IgE crosslinking-induced luciferase expression (EXiLE) for walnut allergy compared with the walnut-specific IgE (sIgE) test, Jug r 1-sIgE test, and skin prick test.

Design/Methods: This retrospective study analyzed 55 patients tested for walnut allergy at Fujita Health University Bantane Hospital from January 2021 to December 2023. Among them, 38 had allergic reactions to walnuts based on history or oral food challenges, and 17 did not. We evaluated the sensitivity, specificity, positive predictive value, negative predictive value, and the area under the curve (AUC) of the receiver operating characteristic curve.

Results: The EXiLE method (AUC = 0.938) exhibited superior diagnostic accuracy compared to walnut-sIgE, and comparable performance to Jug r 1-sIgE and skin prick test. The optimal cutoff value of 1.26-fold change demonstrated high sensitivity (0.92), specificity (0.88), positive predictive value (0.92), and negative predictive value (0.82). The EXiLE method yielded positive results in all three cases with negative Jug r 1-sIgE ( < 0.35 UA/mL).

Conclusion(s): The EXiLE method showed high sensitivity and specificity for diagnosing walnut allergy, indicating its potential clinical utility. Furthermore, the combination of Jug r 1-sIgE and EXiLE may improve the risk assessment of allergy symptom induction upon walnut ingestion, potentially providing a safer and more accurate diagnosis for patients. Future large-scale studies are warranted to confirm these findings and establish comprehensive diagnostic protocols.