Food and Drug Reactions and Anaphylaxis
Wheat ω-5 gliadin is a major allergen in children with immediate allergy to ingested wheat,☆☆

https://doi.org/10.1067/mai.2001.118602Get rights and content

Abstract

Background: Sensitization to wheat by ingestion can lead to food allergy symptoms and wheat-dependent, exercise-induced anaphylaxis. Sensitization by inhalation causes bakers' asthma and rhinitis. Wheat allergens have been characterized at the molecular level in bakers' asthma and in wheat-dependent, exercise-induced anaphylaxis, in which ω-5 gliadin (Tri a 19) is a major allergen. However, little information is available regarding allergens responsible for hypersensitivity reactions to ingested wheat in children. Objective: The aim of this study was to examine whether children with allergy to ingested wheat have IgE antibodies to ω-5 gliadin. Methods: Sera were obtained from 40 children (mean age, 2.5 years; range, 0.7-8.2 years) with suspected wheat allergy who presented with atopic dermatitis and/or gastrointestinal and/or respiratory symptoms. Wheat allergy was diagnosed with open or double-blinded, placebo-controlled oral wheat challenge. Wheat ω-5 gliadin was purified by reversed-phase chromatography, and serum IgE antibodies to ω-5 gliadin were measured by means of ELISA. In vivo reactivity was studied by skin prick testing. Control sera were obtained from 22 children with no evidence of food allergies. Results: In oral wheat challenge, 19 children (48%) reacted with immediate and 8 children (20%) with delayed hypersensitivity symptoms. Sixteen (84%) of the children with immediate symptoms had IgE antibodies to purified ω-5 gliadin in ELISA. In contrast, IgE antibodies to ω-5 gliadin were not detected in any of the children with delayed or negative challenge test results or in the control children. The diagnostic specificity and positive predictive value of ω-5 gliadin ELISA were each 100% for immediate challenge reactions. Skin prick testing with ω-5 gliadin was positive in 6 of 7 children with immediate challenge symptoms and negative in 2 children with delayed challenge symptoms. Conclusion: The results of this study show that ω-5 gliadin is a significant allergen in young children with immediate allergic reactions to ingested wheat. IgE testing with ω-5 gliadin could be used to reduce the need for oral wheat challenges in children. (J Allergy Clin Immunol 2001;108:634-8.)

Section snippets

Patients

Serum samples were collected from 40 children (mean age, 2.5 years; range, 0.7-8.2 years) who had been referred to the Helsinki University Hospital for Skin and Allergic Diseases (n = 29) or to the Tampere University Hospital (n = 11) for evaluation of suspected food allergy. The clinical histories of all 40 children were suggestive of wheat allergy, and at initial examination 23 of them had a positive skin prick test (SPT) result to wheat (1:10 w/v 0.9% NaCl, prepared as previously described8)

Oral wheat challenge

Nineteen children (48%) reacted with immediate hypersensitivity symptoms, including urticaria, erythema, and upper and lower respiratory and abdominal symptoms (Table I). One child experienced an anaphylactic reaction requiring emergency treatment. Eight children (20%) reacted with delayed symptoms, showing flare-up AD and/or diarrhea (Table I). Thirteen children (32%) remained challenge-negative.

IgE antibodies to ω-5 gliadin in ELISA

Sixteen children (84%) with immediate challenge symptoms had IgE antibodies to ω-5 gliadin in ELISA

Discussion

The results of this study show that the presence of IgE antibodies to ω-5 gliadin, a major allergen in wheat-dependent, exercise-induced anaphylaxis, associates strongly with immediate symptoms on oral wheat challenge in young children with food allergy symptoms. On the contrary, IgE antibodies to ω-5 gliadin were not detected in children with delayed or no symptoms in oral wheat challenge. This suggests that ω-5 gliadin is a potent sensitizer not only in adults with exercise-induced anaphylaxis

Acknowledgements

We thank Mrs Leena Petman for expert skin prick testing and Mrs Sari Tillander for technical assistance. We are grateful to Laura Linkosalo, MD, for the control sera.

References (32)

  • SH Sicherer et al.

    Food hypersensitivity and atopic dermatitis: pathophysiology, epidemiology, diagnosis, and management

    J Allergy Clin Immunol

    (1999)
  • SH Sicherer

    Determinants of systemic manifestations of food allergy

    J Allergy Clin Immunol

    (2000)
  • X Baur et al.

    Characterized allergens causing bakers' asthma

    Allergy

    (1998)
  • E Varjonen et al.

    Life-threatening, recurrent anaphylaxis caused by allergy to gliadin and exercise

    Clin Exp Allergy

    (1997)
  • K Palosuo et al.

    Rye γ-70 and γ-35 secalins and barley γ-3 hordein cross-react with ω-5 gliadin, a major allergen in wheat-dependent, exercise-induced anaphylaxis

    Clin Exp Allergy

    (2001)
  • J Fränken et al.

    Identification of α-amylase inhibitor as a major allergen of wheat flour

    Int Arch Allergy Immunol

    (1994)
  • Cited by (0)

    Supported by grants from the Finnish Allergy Research Foundation, the Finnish Medical Society, and the Finnish Society of Allergology and Immunology.

    ☆☆

    Reprint requests: Kati Palosuo, MD, Laboratory of Immunotoxicology, Finnish Institute of Occupational Health, Topeliuksenkatu 41 b, 00250 Helsinki, Finland.

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