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.