1. Division of Gastroenterology and Hepatology, Department of Internal Medicine, Kawasaki Municipal Tama Hospital
2. Tama Medical Practice Center, Kawasaki Municipal Tama Hospital
3. Division of General Internal Medicine, Department of Internal Medicine, Kawasaki Municipal Tama Hospital
4. Division of Gastroenterology and Hepatology, Department of Internal Medicine, St. Marianna University School of Medicine
5. Digestive Disease Center, Yokohama General Hospital
6. Department of Virology II, National Institute of Infectious Diseases
7. Division of Infectious Diseases, Advanced Clinical Research Center, The Institute of Medical Science, The University of Tokyo