1. Division of Rheumatology, Department of Medicine, University of Alberta, Edmonton, AB T6G 2R7, Canada
2. Division of Vascular Medicine, Department of Internal Medicine, University Medical Centre Groningen, University of Groningen, 9700 RB Groningen, The Netherlands
3. Division of Dermatology, Department of Medicine, University of Alberta, Edmonton, AB T6G 2R3, Canada