[1] Rigshosp, Univ Hosp, Dept Pediat & Adolescent Med, DK-2100 Copenhagen, Denmark
[2] Univ Tampere, Div Hematol Oncol, Dept Pediat, FIN-33101 Tampere, Finland
[3] Univ Gothenburg, Dept Pediat, Inst Clin Sci, Sahlgrenska Acad, Gothenburg, Sweden
[4] Univ Oslo, Dept Pediat, Oslo Univ Hosp, Fac Med, Oslo, Norway
[5] Univ Copenhagen, Inst Gynecol Obstet & Pediat, Fac Med, Copenhagen, Denmark