1. Department of Pulmonary and Critical Care Medicine, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Korea.
2. Department of Rheumatology, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Korea.
3. Department of Radiology, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Korea.
4. Department of Pathology, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Korea.
5. Department of Laboratory Medicine and Pathology, Mayo Clinic, Scottsdale, AZ, USA.