Children with wheat anaphylaxis and with low wheat specific IgE have a different IgE immunoblot pattern than those with high wheat specific IgE

Abstract

Background: Children with wheat anaphylaxis can present with a wide range of wheat-specific IgE (sIgE). Objective: To identify differences in clinical features and predominant wheat allergens sensitized by these patients. Methods: Children with history of wheat anaphylaxis were recruited. Skin prick test (SPT) to wheat, sIgE to wheat, omega-5 gliadin (ω5G), lipid transfer protein (LTP) were investigated. Profiles of IgE-bound wheat allergens were studied to identify predominant wheat allergens. Results: Twenty-nine children (17 males) aged 1-18 years were enrolled. Sixteen patients (55.2%) had wheat-sIgE > 100 kUA/L (WA<inf>hi</inf>) and 13 patients (44.8%) had wheat-sIgE < 34 kUA/L (WA<inf>lo</inf>). The median of peak wheat-sIgE in WA<inf>hi</inf> and WA<inf>lo</inf> were 340.5 kUA/L (IQR 184.3, 564.5) and 12.2 kUA/L (IQR 1.4, 41.3), respectively. Oral food challenge test (OFC) was carried out in 12 of 13 patients in the WA<inf>lo</inf> group, all of which had positive results. Eight of these 12 patients developed anaphylaxis during OFC despite having wheat-sIgE less than 10 kUA/L. There were no differences in clinical characteristics and atopic history between WA<inf>hi</inf> vs. WA<inf>lo</inf> . Medium to low molecular weight gliadin (< 40 kDa) and glutenin (< 60 kDa) were commonly recognized by patients with WA<inf>hi</inf>. IgE immunoblot pattern among the WA<inf>lo</inf> group was more widely dispersed than those with WA<inf>hi</inf>. Conclusion: Wheat anaphylaxis can occur in patients with low wheat-sIgE. Predominant wheat allergens recognized by patients with WA<inf>lo</inf> were different than those with WA<inf>hi</inf> . Such difference could be responsible for anaphylaxis at even low levels of wheat-sIgE.