1. Department of Rheumatology, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
2. Division of Rheumatology, Allergy and Immunology, Department of Internal Medicine, University of Toledo Medical Center, Toledo, OH, USA
3. Centre for Rheumatology, Royal Free Hospital, University College London
4. National Heart and Lung Institute, Imperial College London, London, UK
5. Department of Experimental and Clinical Medicine, Division of Rheumatology, University of Florence, Florence, Italy