1. Department of Gastroenterology and Hepatology, Yokosuka Kyosai Hospital, Japan
2. Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University, Japan
3. Department for Liver Disease Control, Tokyo Medical and Dental University, Japan
4. Department of Virology II, National Institute of Infectious Diseases, Japan
5. Department of Pathology, Yokosuka Kyosai Hospital, Japan