1. Department of Respiratory and Critical Care Medicine, Shenzhen Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Southern University of Science and Technology, The Second Medical College of Jinan University, Shenzhen People's Hospital, Shenzhen, Guangdong 518020, P.R. China
2. Department of Allergy and Clinical Immunology, Guangzhou Institute of Respiratory Health, State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, P.R. China
3. Department of Respiratory and Critical Care Medicine, Guangzhou Institute of Respiratory Health, State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, P.R. China
4. Department of Radiology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, P.R. China
5. Airway Disease Section, National Heart and Lung Institute, Imperial College London and Royal Brompton and Harefield NHS Foundation Trust, London SW3 6LY, UK