1. Department of Hematology, VU University Medical Center, Amsterdam, The Netherlands;
2. Department of Hematology, University Hospital, Zurich, Switzerland;
3. Department of Hematology, Gasthuisberg, Leuven, Belgium;
4. HOVON Data Center, Erasmus Medical Center, Rotterdam, The Netherlands;
5. Department of Hematology, Academic Medical Center, Amsterdam, The Netherlands;
6. Department of Hematology, Hospital Network Antwerp-Stuivenberg-Middelheim, Antwerp, Belgium;
7. Department of Hematology, St Luc, Brussels, Belgium;
8. Department of Hematology, MT Godinne, Yvoir, Belgium;
9. Department of Hematology, Erasmus Medical Center, Rotterdam, The Netherlands;
10. Department of Hematology, Leiden University Medical Center, Leiden, The Netherlands;
11. Department of Internal Medicine, Medical Center, Leeuwarden, The Netherlands;
12. Department of Internal Medicine, Albert Schweitzer Hospital, Dordrecht, The Netherlands;
13. Department of Internal Medicine, Sophia Hospital, Zwolle, The Netherlands;
14. Department of Hematology, Inselspital, Bern, Switzerland;
15. Department of Hematology, University Hospital, Maastricht, The Netherlands,
16. Department of Hematology, University Medical Center, Groningen, The Netherlands;
17. Department of Internal Medicine, Antonius Hospital, Nieuwegein, The Netherlands;
18. Department of Hematology, Leyenburg, Den Haag, The Netherlands; and
19. Department of Hematology, University Hospital, Basel, Switzerland