1. Department of Hematology, Graduate School of Comprehensive Human Sciences University of Tsukuba Tsukuba Japan
2. Department of Hematology, Faculty of Medicine University of Tsukuba Tsukuba Japan
3. Department of Hematology University of Tsukuba Hospital Tsukuba Japan
4. Department of Pathology, Faculty of Medicine University of Tsukuba Tsukuba Japan
5. Department of Pathology Jichi Medical University Shimotsuke Japan