1. Department of Clinical and Experimental Haematology; Institute of Clinical Medicine; University of Tsukuba; Tsukuba Japan
2. Ibaraki Clinical Education and Training Centre; University of Tsukuba Hospital; Tsukuba Ibaraki Japan
3. Department of Haematology; Ibaraki Prefectural Central Hospital; Tsukuba Ibaraki Japan
4. School of Medicine; University of Tsukuba; Tsukuba Japan
5. Division for Health Service Promotion; The University of Tokyo; Bunkyo-ku, Tokyo Japan
6. Department of Pathology; Institute of Clinical Medicine; University of Tsukuba; Tsukuba Japan
7. Department of Neurosurgery; Institute of Clinical Medicine; University of Tsukuba; Tsukuba Japan