1 Centre for Epidemiology Versus Arthritis, Division of Musculoskeletal and Dermatological Science, School of Biological Sciences, Faculty of Biological Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK.
2 Division of Immunology and Rheumatology, Department of Medicine, Stanford University, Stanford, CA, USA.
3 Centre for Rheumatic Diseases, King's College London, London, UK.