1. Department I of Internal Medicine and German CLL Study Group, Center for Integrated Oncology Aachen Bonn Cologne Duesseldorf (CIO ABCD) University of Cologne, Faculty of Medicine and University Hospital Cologne Cologne Germany
2. Department of Hematology and Stem Cell Transplantation, West German Cancer Center University of Duisburg‐Essen Essen Germany
3. Department of Hematology, Cancer Center Amsterdam Amsterdam University Medical Centers, University of Amsterdam Amsterdam Netherlands
4. Department of Internal Medicine Rijnstate Hospital Arnhem Netherlands
5. Department of Hematology Rigshospitalet Copenhagen Denmark
6. Department of Internal Medicine III, Division of CLL University Hospital Ulm Ulm Germany