1. Department of Rheumatology, Dr Daniel den Hoed Clinic
2. Institute of Hematology, Erasmus University of Rotterdam, Rotterdam
3. Department of Internal Medicine, St Joseph Hospital, Veldhoven
4. Department of Nuclear Medicine
5. Department of Pathology, Dr Daniel den Hoed Clinic, Rotterdam
6. Department of Rheumatology, University Hospital Leiden, Leiden, The Netherlands