1. 1st Department of Internal Medicine and Centre for Integrated Oncology CIO Köln/Bonn, University Hospital of Cologne, Cologne, Germany German CLL Study Group (GCLLSG), Cologne, Germany
2. German CLL Study Group (GCLLSG), Cologne, Germany
3. Department of Geriatric Medicine, St Marien Hospital, Cologne, Germany
4. Klinik I für Innere Medizin, Kerpener Straße 62, 50937 Köln, Germany