1. Department of Pediatrics, Nara Medical University, Kashihara, Japan;
2. Department of Hematology, Ogikubo Hospital, Tokyo, Japan;
3. Department of Pediatrics, St Marianna University School of Medicine, Kawasaki, Japan;
4. Department of Transfusion Medicine, Nagoya University, Nagoya, Japan;
5. Department of Pediatrics, University of Occupational and Environmental Health, Kitakyushu, Japan;
6. Department of Laboratory Medicine, Tokyo Medical University, Tokyo, Japan; and
7. Chugai Pharmaceutical Co., Ltd, Tokyo, Japan