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

Nuntanut Rutrakool,¹ Surapon Piboonpocanun,² Unchalee Wangthan,¹ Witchaya Srisuwatchari,¹ Torpong Thongngarm,³ Orathai Jirapongsananuruk,¹ Nualanong Visitsunthorn,¹ Pakit Vichyanond,⁴ Punchama Pacharn¹

Affiliations:
¹ Division of Allergy and Immunology, Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
² Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakhon Pathom, Thailand
³ Division of Allergy and Immunology, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
⁴ Samitivej Allergy Institute, Samitivej Thonburi Hospital, Bangkok, Thailand

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_hi) and 13 patients (44.8%) had wheat-sIgE < 34 kUA/L (WA_lo). The median of peak wheat-sIgE in WA_hi and WA_lo 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_lo 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_hi vs. WA_lo. Medium to low molecular weight gliadin (< 40 kDa) and glutenin (< 60 kDa) were commonly recognized by patients with WA_hi. IgE immunoblot pattern among the WA_lo group was more widely dispersed than those with WA_hi.
Conclusion: Wheat anaphylaxis can occur in patients with low wheat-sIgE. Predominant wheat allergens recognized by patients with WA_lo were different than those with WA_hi. Such difference could be responsible for anaphylaxis at even low levels of wheat-sIgE.
Key words: wheat hypersensitivity, food hypersensitivity, anaphylaxis, immunoblotting, gliadin