1 Royal National Hospital for Rheumatic Diseases, Royal United Hospitals Foundation Trust, Bath; and University of Bath, UK.
2 University of Bath, UK.
3 Johns Hopkins University School of Medicine, Baltimore, MD, USA.
4 Salford Royal NHS Foundation Trust, UK.
5 Department of Dermatology and Venereology, Medical University of Sofia, Bulgaria.
6 Department of Rheumatology, University Hospital Zurich, Switzerland.
7 Salford Royal NHS Foundation Trust; National Institute of Health Research Manchester Musculoskeletal Biomedical Research Unit, Centre for Musculoskeletal Research, University of Manchester; and Central Manchester Foundation Trust, UK.