1. Department of Internal Medicine III, and
2. Department of Medical Informatics, Biometry, and Epidemiology, University of Munich, Munich, Germany;
3. Institute of Pathology, Lymph Node Registry, University of Kiel, Kiel, Germany;
4. Department of Hematology, Hôpital Saint Louis, Paris, France;
5. Department of Hematology, Akademisch Ziekenhuis St-Jan, Bruges, Belgium;
6. Department of Hematology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands;
7. Department of Internal Medicine I, Saarland University Medical School, Homburg, Germany;
8. Department of Internal Medicine I, University of Cologne, Cologne, Germany;
9. Department of Oncology and Hematology, Klinikum Oldenburg, Oldenburg, Germany;
10. Department of Internal Medicine II, University Hospital of Würzburg, Würzburg, Germany;
11. Department of Hematology/Oncology, Carl-Thiem Hospital, Cottbus, Germany;
12. Department of Hematology and Oncology, University of Göttingen, Göttingen, Germany;
13. Städtisches Klinikum Braunschweig, Braunschweig, Germany;
14. Department of Hematology and Oncology, Helios Klinikum Berlin-Buch, Berlin, Germany;
15. Department of Hematology, University Hospital Essen, Essen, Germany;
16. Department of Hematology and Oncology, Katholisches Krankenhaus Hagen, Hagen, Germany; and
17. Medical Department 5, Klinikum Nürmberg Nord, Nuremberg, Germany