1. Department of Hematology/Oncology Wakayama Medical University Wakayama Japan
2. Department of Virology and Parasitology Hamamatsu University School of Medicine Shizuoka Japan
3. Department of Virology II National Institute of Infectious Disease Tokyo Japan
4. Department of Hematology Sakai City Medical Center Osaka Japan
5. Center for Surveillance, Immunization, and Epidemiologic Research National Institute of Infectious Disease Tokyo Japan
6. Department of Hematology Japanese Red Cross Kyoto Daiichi Hospital Kyoto Japan
7. Department of General Medicine National Hospital Organization Kumamotominami National Hospital Kumamoto Japan