1. Division of TransfusionOkayama University Hospital Okayama Japan
2. Department of Hematology and OncologyOkayama University Hospital Okayama Japan
3. Japanese Red Cross Chugoku‐Shikoku Block Blood Center Hiroshima Japan
4. Japanese Red Cross Okayama Blood Center Okayama Japan
5. Department of General MedicineOkayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Okayama Japan