1. Department of Immunology Genetics and Pathology Uppsala University Uppsala Sweden
2. Division of Clinical Epidemiology, Department of Medicine Karolinska Institutet Stockholm Sweden
3. Department of Women's and Children's Health Uppsala University Uppsala Sweden
4. Department of Epidemiology Research Statens Serum Institut Copenhagen Denmark
5. Department of Haematology Rigshospitalet Copenhagen Denmark
6. Danish Cancer Society Research Center University of Copenhagen Copenhagen Denmark
7. Department of Haematology Aarhus University Hospital Aarhus Denmark
8. Department of Paediatrics and Adolescent Medicine Rigshospitalet Copenhagen Denmark