[1] Karolinska Univ Hosp, Dept Womens & Childrens Hlth, Childhood Canc Res Unit, Stockholm, Sweden
[2] Karolinska Inst, Stockholm, Sweden
[3] Aalborg Univ Hosp, Dept Paediat, Aalborg, Denmark
[4] Univ Helsinki, Cent Hosp, Childrens Hosp, Helsinki, Finland
[5] Univ Helsinki, Cent Hosp, Ctr Canc, Dept Haematol, Helsinki, Finland
[6] Aarhus Univ Hosp, Dept Paediat, DK-8000 Aarhus, Denmark
[7] Lund Univ, Dept Paediat, Univ Hosp, Malmo, Sweden
[8] Lund Univ, Dept Coagulat Disorders, Univ Hosp, Malmo, Sweden
[9] Skane Univ Hosp, Dept Paediat Haematol & Oncol, Malmo, Sweden
[10] Skane Univ Hosp, Dept Paediat Haematol & Oncol, Lund, Sweden
[11] Landspitali Univ Hosp, Childrens Hosp, Reykjavik, Iceland
[12] Tallinn Childrens Hosp, Dept Haematol Oncol, Tallinn, Estonia
[13] Haukeland Hosp, Dept Paediat, N-5021 Bergen, Norway
[14] Vilnius Univ Hosp, Santariskiu Klin, Childrens Hosp, Ctr Paediat Oncol & Haematol, Vilnius, Lithuania
[15] Rigshosp, Copenhagen Univ Hosp, Dept Paediat & Adolescent Med, DK-2100 Copenhagen, Denmark
[16] Rigshosp, Oslo Univ Hosp, Dept Paediat Med, DK-2100 Copenhagen, Denmark