1. Department of Pediatrics University of Ryukyus Hospital Nakagami‐gun Japan
2. Okinawa Prefectural Red Cross Blood Center Naha Japan
3. Department of Pathology and Oncology, Graduate School of Medicine University of Ryukyus Nakagami‐gun Japan
4. Department of Pediatrics, Graduate School of Medicine University of Nagoya Nagoya Japan
5. Department of Pediatrics, Graduate School of Medicine University of The Ryukyus Nakagami‐gun Japan