Sensitisation to Cor a 14 and Cor a 9 is a risk marker for severe hazelnut allergy in children

摘要

BackgroundHazelnut-allergic children express variable clinical phenotypes.Tests for the diagnosis of hazelnut allergy areusually conducted on children presenting clinical symptomsfollowing hazelnut ingestion, but also as screeningtests after the discovery of a food allergy, mainly to treenut or peanut. It is important to determine if molecularallergens could be markers of severity in hazelnut allergy.ObjectivesTo evaluate the usefulness of hazelnut molecular allergensin children with suspected hazelnut allergy. To studywhether these allergens might predict the severity of hazelnutallergy.Method41 hazelnut-sensitized children (69% males, mean age: 8.1years) were divided into 2 groups: - 29 patients with severeallergy i.e. angioedema, urticaria, emesis or hoarseness afteringestion of crude or roasted hazelnut, or children withpositive prick-tests to roasted hazelnut. - 12 patients withmild allergy i.e. an oral allergy syndrome after ingestion ofcrude hazelnut, or children under hazelnut free diet due toa strongly positive prick-test to crude hazelnut performedafter an allergic reaction to another tree nut or peanut.Specific IgE against 4 hazelnut allergens (rCor a 1, rCor a8, rCor a 9, rCor a 14) were determined for each patient,using the ImmunoCap? 250 system (Thermo Fisher).ResultsOn the whole population, IgE positivity to Cor a 14 (73%),Cor a 9 (56%) and Cor a 1 (37%) are the most frequent.Conversely, only 2 children had positive IgE against Cor a8. Children with severe allergy were all positive for Cor a14 (93%) or Cor a 9 (76%), and 69% were positive for both.Only 10% of them had IgE against Cor a 1. Children withmild allergy were all IgE positive for Cor a 1. 67% werepositive only for Cor a 1. 25% were also positive for Cor a14 and 8% for Cor a 9. None of them were positive forboth Cor a 9 and Cor a 14. Most of these children werepollinic (75%).Conclusion2 clinical phenotypes of hazelnut allergy can be clearly distinguishedusing molecular allergens: - Sensitization toseed storage proteins (Cor a 9 or Cor a 14) is a strongmarker of severe allergy, even more specific when bothmolecular allergens are positive. - Sensitization to Cor a 1defines a PR-10 profile specific for children with a mildallergy which is often associated with pollen allergy. Thus,testing Cor a 9, Cor a 14 and Cor a 1 specific IgE is ofgreat help in identifying children at risk for severe allergicreactions to hazelnut.