1 Department of Internal Medicine, Leuven University, Leuven, Belgium.
2 Department of Haematology, AZ Sint-Jan Brugge AV, Bruges, Belgium.
3 Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta; and Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
4 Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
5 Department of Rheumatology and Clinical Immunology, University Medical Center Utrecht, Utrecht, the Netherlands.
6 Department of Rheumatology, AZ Sint-Jan Brugge AV, Bruges, and Department of Rheumatology, and Department of Internal Medicine, Ghent University, Ghent, Belgium. [email protected].