1. Department of Microbiology, Graduate School of Medicine, Gachon University of Medicine and Science, Incheon 406-799, Korea.
2. Department of Biochemistry, Graduate School of Medicine, Gachon University of Medicine and Science, Incheon 406-799, Korea.
3. Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul 110-746, Korea.