Désirée van der Heijde1, Xenofon Baraliakos2, Joachim Sieper3, Atul Deodhar4, Robert D Inman5, Hideto Kameda6, Xiaofeng Zeng7, Yunxia Sui8, Xianwei Bu8, Aileen L Pangan8, Peter Wung8, In-Ho Song8. 1. Rheumatology, Leiden University Medical Center, Leiden, The Netherlands mail@dvanderheijde.nl. 2. Rheumazentrum Ruhrgebiet Herne, Ruhr-University Bochum, Herne, Germany. 3. Gastroenterology, Infectious Diseases and Rheumatology, Charité Universitätsmedizin Berlin, Berlin, Germany. 4. Division of Arthritis & Rheumatic Diseases, Oregon Health & Science University, Portland, Oregon, USA. 5. Schroeder Arthritis Institute, University Health Network, and University of Toronto, Toronto, Ontario, Canada. 6. Internal Medicine, Toho University, Tokyo, Japan. 7. Rheumatology and Clinical Immunology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education, National Clinical Research Center for Dermatologic and Immunologic Diseases (NCRC-DID), Beijing, China. 8. Immunology, AbbVie Inc, North Chicago, Illinois, USA.