1. Division for Stem Cell Transplantation, Immunology and Intensive Care Medicine, Department for Children and Adolescents Goethe University Frankfurt/Main Germany
2. German Red Cross Blood Service Baden‐Württemberg‐Hessen Institute Frankfurt/Main Frankfurt/Main Germany
3. Institute for Transfusion Medicine and Immunohematology Goethe University Frankfurt/Main Germany
4. Division of Hematology, Department of Medicine University of Washington Seattle Washington USA