1. Department of Otolaryngology/Head and Neck Surgery, Haukeland University Hospital, 5009 Bergen, Norway
2. Department of Surgery, Haraldsplass Deaconal Hospital, 5009 Bergen, Norway
3. Department of Clinical Medicine, Faculty of Medicine, University of Bergen, 5007 Bergen, Norway
4. Section for Haematology, Department of Medicine, Haukeland University Hospital, 5009 Bergen, Norway
5. Department of Haematology, Oslo University Hospital, Rikshospitalet, 0372 Oslo, Norway