Departments of *Pediatrics and Adolescent Medicine
†Clinical Immunology, University Hospital Rigshospitalet
§Institute of Gynaecology, Obstetrics and Paediatrics, The Faculty of Medicine University of Copenhagen Copenhagen, Denmark
‡Department of Pediatrics University Hospital Lund Lund, Sweden
Supported by The Danish Childhood Cancer Foundation and The Danish Cancer Society (Grant no. R52-A2819).
The authors declare no conflict of interest.