Hung-Chih Yang1,2,3, Jia-Horng Kao4,5,6. 1. Department of Microbiology, National Taiwan University College of Medicine, Taipei, Taiwan. 2. Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine, Taipei, Taiwan. 3. Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan. 4. Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine, Taipei, Taiwan. kaojh@ntu.edu.tw. 5. Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan. kaojh@ntu.edu.tw. 6. Hepatitis Research Center, National Taiwan University Hospital, Taipei, Taiwan. kaojh@ntu.edu.tw.