aUpper Airways Research Laboratory, Faculty of Medicine, Ghent University, Ghent, Belgium

bDivision of ENT Diseases, CLINTEC, Karolinska Institute, Stockholm, Sweden

cFirst Affiliated Hospital, Sun Yat-Sen University, International Airway Research Center, Guangzhou, China

Correspondence to Claus Bachert, MD, PhD, Upper Airways Research Laboratory, Department Head & Skin, Ghent University, UZ Ghent, C. Heymanslaan 10, 9000 Ghent, Belgium. Tel: +32 9 332 2363; e-mail: [email protected]