Specific IgE Decision Point Cutoffs in Children with IgE-Mediated Wheat Allergy and a Review of the Literature

Abstract

<b><i>Background:</i></b> Wheat IgE-mediated food allergy in children is one of the most frequent food allergies in westernized countries, affecting between 0.4 and 1% of children. Although 95% predictive decision points have been determined for major allergens such as peanut, egg, and milk, the diagnostic performances of wheat-specific IgE (sIgE) and wheat component testing are not well established. <b><i>Objectives:</i></b> The aim of this study was to determine sIgE decision point cutoffs in children with IgE-mediated wheat allergy and provide a review of the literature. <b><i>Method:</i></b> A retrospective review of wheat oral food challenges was performed at the pediatric allergy unit of the University Hospitals of Geneva between 2004 and 2019. Performance characteristics for wheat and ω-5 gliadin sIgE were calculated and positive and negative OFC data were compared using the Mann-Whitney U test. <b><i>Results:</i></b> A wheat sIgE cutoff of 2.88 kU<sub>A</sub>/L had a sensitivity of 95% (negative decision point), whereas a cutoff of 78.1 kU<sub>A</sub>/L had a specificity of 95% (positive decision point). When giving equal weight to sensitivity and specificity, the optimal cutoff point for wheat sIgE was 12 kU<sub>A</sub>/L, which gave a specificity of 70% and a sensitivity of 66.67%. <b><i>Conclusions:</i></b> These findings suggest a high positive decision point for wheat sIgE (78.1 kU<sub>A</sub>/L). This reinforces the importance of considering OFC in children with IgE-mediated wheat allergy to confirm diagnosis even in patients with relatively high wheat sIgE values, as there is a risk of falsely mislabeling these patients as allergic.

Serum Allergen-Specific IgE among Pediatric Patients with Primary Immunodeficiency

“…According to some studies, the cut-off level of 0.35 kUa/L for allergen-specific IgE might be insufficient to predict clinical reactivity [18][19][20][21][22]. For example, in the study by Garcia-Ara et al, it was shown that different cut-off points for specific IgE levels for milk and casein, which indicated clinical reactivity, were found at different ages.…”

Specific IgE to Total IgE Ratio Does Not Improve Peanut Diagnostic Accuracy in Adults

“…The inclusion of an adult population (median age 26 years) represents a strength, since, to our knowledge, this is the first study to have looked at the benefit of sIgE to tIgE ratio for the diagnosis of peanut allergy in this population. This provides data for clinicians who often apply pediatric data to their adult population since most literature discussing food allergy diagnosis is conducted in young pediatric populations with median ages ranging from 13 months to 10 years [3,5,6,[8][9][10].…”

“…Specific IgE values can be influenced by multiple factors, including age and the presence of atopic dermatitis [2,3] and were also shown to correlate with total IgE levels [4], with a pediatric study demonstrating that the probability of having a positive OFC decreases when total IgE increases [5]. However, the benefit of sIgE to tIgE ratio in predicting OFC outcomes is inconsistent, with some pediatric studies supporting improved diagnostic accuracy [6,7] and others failing to show a benefit [8,9].…”

Systematic review and meta‐analyses on the accuracy of diagnostic tests for IgE‐mediated food allergy

“…We included 16 studies on accuracy of diagnostic tests for wheat allergy. For meta-analyses, there were 5 studies of SPT to wheat , 36,82,104,114,136,154,156,178 10 of sIgE to whe at 32,36,55,56,77,104,114,128,130,136,150,154,158,178 and 6 of ω-5 gliadin-sIgE 32,56,77,128,130,136 with pooled sensitivities of 53%, 72% and 79% and specificities of 72%, 79% and 78%, respectively (Table 2 and…”