Age-related sensitization profiles for hazelnut (**Corylus avellana**) in a birch-endemic region
Faculty of Medicine and Health Sciences
Pediatric allergy and immunology. - Copenhagen
, p. e139-e149
University of Antwerp
Background: Symptoms of hazelnut allergy seem related to geographic and possibly agevariations in allergen recognition. Objective: To investigate sensitization profiles of hazelnut allergy in different age-groups in a birch-endemic region using component resolved diagnosis by microarray. Methods: Sixty-five hazelnut allergic patients, 27 healthy control individuals tolerant to hazelnut and 34 birch pollen allergic but hazelnut tolerant individuals were included. All blood samples were analysed using ISAC microarray. Results: Twenty-nine hazelnut allergic patients suffered from a systemic reaction (17 preschool children with a median age of 2 years, 6 school children and 6 adults) whereas 36 patients reported an oral allergy syndrome (OAS; 3 preschool- and 9 school children and 24 adults). In the hazelnut allergic preschool children with systemic reactions, 65% were sensitized to Cor a 9, 12% to Cor a 8, 18% to Cor a 1.04, 6% to Cor a 1.0101 and 29% to Bet v 1. Of the school aged systemic reactors, 50% were sensitized to Cor a 9, 17% to Cor a 8, 50% to Cor a 1.04 and Cor a 1.0101 and 67% to Bet v 1. In adults with hazelnut allergy, 3.3% was sensitized to Cor a 9, 6.7% to Cor a 8, 90% to Cor a 1.04 and Bet v 1 and 87% to Cor a 1.0101. In regard to systemic reactors in this group, 17% was sensitized to Cor a 9, 33% to Cor a 8 and Cor a 1.0101 and 50% to Cor a 1.04 and Bet v 1. In the OAS patients, irrespective the age group, all were sensitized to Bet v 1 and over 97% to Cor a 1.04 and Cor a 1.0101. No Page 2 of 32 Scholarone, Inc. Support (434) 964 4100 Pediatric Allergy and Immunology For Peer Review sensitization to Cor a 9 or Cor a 8 was found in patients with only an OAS. Of the birch pollen allergic patients, tolerant to hazelnut, none were sensitized to Cor a 9 or Cor a 8, 56% to Cor a 1.0101, 82% were sensitized to Cor a 1.04 and 92% to Bet v 1. In healthy controls, no sensitization to components of hazelnut, hazel- or birch pollen was demonstrable. Conclusion: Hazelnut allergy in a birch-endemic region exhibits age-related sensitization profiles with distinct clinical outcomes that can be identified using component resolved diagnosis. The majority of hazelnut allergic preschool- and school children in a birch-endemic region show systemic reactions on consumption of processed hazelnut, mostly being sensitized to the hazelnut legumin-like allergen Cor a 9 but unrelated to birch pollen allergy. In contrast, adults generally suffer from an OAS apparently as a result of cross-reactivity between Cor a 1.04 from hazelnut and Bet v 1 from birch pollen.