1. Department of Haematology; Radboud University Nijmegen Medical Centre; Nijmegen; the Netherlands
2. Department of Haematology; Erasmus University Medical Centre; Rotterdam; the Netherlands
3. Department of Pathology; Erasmus University Medical Centre; Rotterdam; the Netherlands
4. Department of Tumour Immunology; Radboud University Nijmegen Medical Centre; Nijmegen; the Netherlands