1 Department of Hematology, Juntendo University School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan. komatsun@juntendo.ac.jp.
2 Department of Hematology and Oncology, University of Yamanashi, Yamanashi, 409-3898, Japan.
3 Department of Gastroenterology and Hematology, University of Miyazaki, Miyazaki, 889-1692, Japan.
4 Department of Hematology, Kobe City Medical Center General Hospital, Kobe, 650-0047, Japan.