1. Department of Internal Medicine, Konkuk University School of Medicine, Seoul, Korea.
2. Division of Infectious Diseases, Department of Internal Medicine, Kyung Hee University Medical Center, Seoul, Korea.
3. Division of Infectious Diseases, Department of Internal Medicine, Chung-Ang University Hospital, Seoul, Korea.
4. Department of Laboratory Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
5. Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.