1. Department of Pediatrics, Willem‐Alexander Children's Hospital, Leiden University Medical Center Division of Stem Cell Transplantation Leiden The Netherlands
2. Department of Pediatrics, Willem‐Alexander Children's Hospital, Leiden University Medical Center Division of Psychosocial Care Leiden The Netherlands
3. Department of Internal Medicine Leiden University Medical Center Leiden The Netherlands
4. Department of Biomedical Data Sciences Leiden University Medical Center Leiden The Netherlands