1. Department of Pediatric Hematology, University Medical Center Utrecht, Utrecht, The Netherlands;
2. Department of Pediatrics, Flevo Hospital, Almere, The Netherlands;
3. Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands;
4. Department of Immunohematology Diagnostics, Sanquin Diagnostic Services, Amsterdam, The Netherlands;
5. Department of Pediatric Hematology and Oncology, University Medical Center Groningen, Groningen, The Netherlands;
6. Department of Pediatric Hematology, University Medical Center Leiden, Leiden, The Netherlands;
7. Department of Pediatrics, Meander Medical Center, Amersfoort, The Netherlands;
8. Department of Pediatrics, Rijnstate Hospital, Arnhem, The Netherlands;
9. Department of Experimental Immunohematology, Sanquin Research, and
10. Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands;
11. Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, The Netherlands; and
12. Princess Maxima Center for Pediatric Oncology, Utrecht, The Netherlands