1. Department of Hematology, Fukushima Medical University Aizu Medical Center, Aizuwakamatsu, Fukushima, Japan,
2. Department of Hematology, Fukushima Medical University, Hikarigaoka, Fukushima, Japan,
3. Department of Hematology, Juntendo University Shizuoka Hospital, Izunokuni, Shizuoka, Japan