THE CLINICAL CHARACTERISTICS OF PEANUT ALLERGY AND THE DIAGNOSTIC ACCURACY OF THE SPECIFIC IgE TO Ara h 2

Abstract

This study aimed to evaluate the clinical accuracy of specific IgE (sIgE) to Ara h 2 in the diagnosis of peanut allergy (PA). We also investigated the prevalence of complications with other nut allergies in PA patients. The Ara h 2-sIgE titer was examined in patients with positive results for sIgE to peanut from April 2014 to March 2015. The presence or absence of PA was diagnosed based on an oral food challenge or a convincing clinical history. The characteristics of 217 patients (including 90 PA patients) were retrospectively evaluated. At ≥0.35UA/mL, Ara h 2 showed 85.6% sensitivity in the diagnosis of PA. At the clinically-designated positive cut-off value (≥4.0UA/mL), the positive predictive value was 93.1% and the specificity was 96.9%. However, the Ara h 2-sIgE levels were not correlated with the threshold dose or the severity of the symptoms that were provoked in the peanut challenge (n=42). Nine (10%) of the PA patients also had allergies to other tree nuts. The re-evaluation of the clinically-designated positive Ara h 2-sIgE cut-off value revealed that the cut-off value was appropriate. The differential diagnosis of tree nut allergies was suggested to be important in PA patients.