1. Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, Beijing, China;
2. National Clinical Research Center for Respiratory Diseases, Beijing, China;
3. The Graduate School of Peking Union Medical College, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China;
4. Capital Medical University, Beijing, China;
5. Peking University Health Science Center, Beijing, China