Montserrat Fernandez-Rivas, Simona Belohlavkova, Serge A. Versteeg, Stefan Vieths, Justin T. Marsh, Thuy-My Le, Alison Lovegrove, Karin Hoffmann-Sommergruber, Laurian Zuidmeer-Jongejan, Barbara Ballmer-Weber, Clare Mills, I. Reig, Ruta Dubakiene, Gerald Reese, Náyade del Prado, Suranjith L. Seneviratne, L. Barreales, David Gislason, Aeilko H. Zwinderman, Jonas Lidholm, Riccardo Asero, Ronald van Ree, Ashok Purohit, Monika Jedrzejczak-Czechowicz, André C. Knulst, P. Bures, Nikolaos G. Papadopoulos, Mareen R. Datema, Frédéric de Blay, Todor A. Popov, Athanasios Sinaniotis, Marek L. Kowalski, Michael Clausen, Tanya Kralimarkova, AII - Amsterdam institute for Infection and Immunity, APH - Amsterdam Public Health, Graduate School, Experimental Immunology, Epidemiology and Data Science, 1Department of Experimental Immunology, Academic Medical Center, Amsterdam, The Netherlands. 2Ambulatorio di Allergologia, Clinica San Carlo, Paderno Dugnano, Italy. 3Clinical Epidemiology Unit, Preventive Medicine Department, Hospital Clinico San Carlos, IdISSC, Madrid, Spain. 4Pediatric Department, Faculty Hospital Bulovka, Prague, Czech Republic. 5Allergy Division, Chest Disease Department, University Hospital of Strasbourg, Strasbourg, France. 6Allergy Unit, Department of Dermatology, University Hospital Zürich, Zürich, Switzerland. 7Faculty of Medicine, University of Iceland, Landspitali University Hospital, Reykjavik, Iceland. 8Medical Faculty, Vilnius University, Vilnius, Lithuania. 9Department of Immunology, Rheumatology and Allergy, Faculty of Medicine, Medical University of Lodz, Lodz, Poland. 10Department of Dermatology and Allergology, University Medical Center Utrecht, Utrecht, The Netherlands. 11Clinic of Allergy and Asthma, Medical University of Sofia, Sofia, Bulgaria. 12Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, United Kingdom. 13Institute of Inflammation and Repair, Manchester Institute of Biotechnology, University of Manchester, Manchester, United Kingdom. 14Allergy Department, 2nd Pediatric Clinic, University of Athens, Athens, Greece, Centre for Paediatrics and Child Health, Institute of Human Development, University of Manchester, Manchester, United Kingdom. 15Division of Allergology, Paul-Ehrlich-Insitut, Federal Institute for Vaccines and Biomedicines, Langen, Germany. 16Allergy Department, Hospital Clinico San Carlos, IdISSC, Madrid, Spain. 17Department of Clinical Immunology, St Mary's Hospital, and Imperial College London, London, United Kingdom. 18Allergy Department, 2nd Pediatric Clinic, University of Athens, Athens, Greece. 19Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Centre, Amsterdam, The Netherlands. 20Phadia AB, Uppsala, Sweden. 21Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria. 22Department of Experimental Immunology, Academic Medical Center, Amsterdam, The Netherlands, and Department of Otorhinolaryngology, Academic Medical Center, Amsterdam
Background Hazelnut allergy is birch pollen–driven in Northern/Western Europe and lipid transfer protein–driven in Spain and Italy. Little is known about other regions and other allergens. Objective Establishing a molecular map of hazelnut allergy across Europe. Methods In 12 European cities, subjects reporting reactions to hazelnut (n = 731) were evaluated and sensitization to 24 foods, 12 respiratory allergen sources, and latex was tested by using skin prick test and ImmunoCAP. A subset (124 of 731) underwent a double-blind placebo-controlled food challenge to hazelnut. Sera of 423 of 731 subjects were analyzed for IgE against 7 hazelnut allergens and cross-reactive carbohydrate determinants by ImmunoCAP. Results Hazelnut allergy was confirmed in 70% of those undergoing double-blind placebo-controlled food challenges. Birch pollen–driven hazelnut sensitization (Cor a 1) dominated in most cities, except in Reykjavik, Sofia, Athens, and Madrid, where reporting of hazelnut allergy was less frequent anyhow. In Athens, IgE against Cor a 8 dominated and strongly correlated with IgE against walnut, peach, and apple and against Chenopodium , plane tree, and mugwort pollen. Sensitization to seed storage proteins was observed in less than 10%, mainly in children, and correlated with IgE to nuts, seeds, and legumes. IgE to Cor a 12, observed in all cities (10% to 25%), correlated with IgE to nuts, seeds, and pollen. Conclusions In adulthood, the importance of hazelnut sensitization to storage proteins, oleosin (Cor a 12), and Cor a 8 is diluted by the increased role of birch pollen cross-reactivity with Cor a 1. Cor a 8 sensitization in the Mediterranean is probably driven by diet in combination with pollen exposure. Hazelnut oleosin sensitization is prevalent across Europe; however, the clinical relevance remains to be established.