1. Department of Otorhinolaryngology-Head and Neck Surgery; University Hospitals Leuven; Leuven; Belgium
2. Department of Otorhinolaryngology; Academic Medical Center; Amsterdam; The Netherlands
3. Swiss Intitute of Allergy; Davos; Switzerland
4. Department of Otorhinolaryngology-Head and Neck Surgery; Univeristy of Ghent; Ghent; Belgium
5. Department of Otorhinolaryngology-Head and Neck Surgery; Osmangazi University; Eskilehir; Turkey
6. University Department of ENT; Head and Neck Surgery; Sestre Milosrdnice University Hospital Center; Zagreb; Croatia
7. Royal National Throat, Nose and Ear Hospital; University College; London; UK
8. Rhinology Unit and Smell Clinic; Department of Otorhinolaryngology; Hospital Clinic; Athens; Greece
9. Department of Allergy; 2nd Pediatric Clinic; University of Athens; Athens; Greece
10. Allergy and Respiratory Diseases; Department of Internal Medicine; University of Genoa; Genoa; Italy
11. IDIBAPS; CIBERES; Barcelona; Catalonia; Spain
12. Center for Applied Genomics; Children's Hospital Philadelphia; Philadelphia; PA; USA
13. Department of Respiratory Disease; University Hospital Arnaud de Villeneuve; Montpellier; France