1. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
2. Department of Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
3. Division of Nephrology, Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
4. Transplantation Research Institute, Seoul National University College of Medicine, Seoul, Korea.