1. the Department of Otolaryngology-Head and Neck Surgery, Cathay General Hospital, Taipei
2. the Department of Pathology, Cathay General Hospital, Taipei
3. the School of Medicine, Fu Jen Catholic University, Taipei
4. the School of Public Health, China Medical University, Taichung
5. the Section of Infectious Diseases, Department of Medicine, Cathay General Hospital, Taipei, Taiwan.