1. National Clinical Research Center for Hematologic DiseaseBeijing Key Laboratory of Hematopoietic Stem Cell TransplantationPeking University People's HospitalPeking University Institute of Hematology Beijing 100044 P. R. China
2. Department of HematologyXinqiao HospitalArmy Military Medical University Chongqing 400037 P. R. China
3. Department of PediatricsNanfang HospitalSouthern Medical University Guangzhou Guangdong 510515 P. R. China
4. Peking-Tsinghua Center for Life Sciences Beijing 100871 P. R. China