1 Department of Allergy and Clinical Immunology, Airway Sensation and Cough Research Laboratory, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
2 Department of Allergology, Institution of Internal Medicine, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.
3 Respiratory Research Group, University of Hull, Hull York Medical School, Castle Hill Hospital, Cottingham, East Yorkshire, United Kingdom.