1. Division of Haematology-Oncology and Stem Cell Transplantation, Children's Hospital, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland
2. Unit for Coagulation Disorders, Department of Haematology, Comprehensive Care Center and Cancer Center, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland
3. Astrid Lindgren Children's Hospital, Karolinska University Hospital, Karolinska Institute, Stockholm, Sweden