1. Royal Free Hospital; London UK
2. National Referral Centre for Rare Systemic Auto-immune Diseases; Department of Internal Medicine; Hôpital Huriez; University of Lille; Lille France
3. Charité University of Medicine; Berlin Germany
4. Johannes Gutenberg University; Mainz, and ACURA Rheumatology Centre RLP; Bad Kreuznach Germany
5. Actelion Pharmaceuticals Ltd.; Allschwil Switzerland
6. The University of Manchester; Salford Royal NHS Foundation Trust and NIHR Manchester Musculoskeletal Biomedical Research Centre; Central Manchester NHS Foundation Trust; Manchester Academic Health Science Centre; Manchester UK