1. Asan Institute for Life Science and University of Ulsan College of Medicine, Seoul, Korea.
2. Institute of Convergence Medicine, Ewha Womans University Medical Center and Ewha Womans University School of Medicine, Seoul, Korea.
3. Department of Internal Medicine, Dankook University College of Medicine, Cheonan, Korea.
4. Department of Allergy and Clinical Immunology, Asan Medical Center, Seoul, Korea.
5. Department of Pulmonary and Critical Care Medicine, and Clinical Research Center for Chronic Obstructive Airway Disease, Asan Medical Center, Seoul, Korea.