1. Division of Hematology, Jichi Medical University Hospital
2. Present address: Central Blood Institute, Japanese Red Cross Society
3. Division of Hematology, Saitama Medical Center, Jichi Medical University
4. Center for Community Medicine, Jichi Medical University Hospital
5. Research Hospital, The Institute of Medical Science, The University of Tokyo
6. Division of Cell Transplantation and Transfusion, Jichi Medical University Hospital