Miguel Ferrer, Ann W. Morgan, Beatriz Joven, John D. Isaacs, Theologia Sarafidou, Enrique Raya, Rafael Cáliz, Javier Narváez, Ariana Montes, Ana Márquez, C. Magro, Javier Martín, F. Navarro-Sarabia, Moreira Vf, María del Carmen Ordóñez, Lara Valor, Alejandro Balsa, Antonio Fernández-Nebro, Juan José Alegre-Sancho, Arturo Rodríguez de la Serna, Anne Barton, Rosa Garcia-Portales, Manuel J. Moreno-Ramos, Antonio Gonzalez, Anthony G. Wilson, Francisco J. Blanco, Patricia Carreira, Yiannis Vasilopoulos, Juan J. Gomez-Reino, Darren Plant, Berta Magallares, Juan D. Cañete, Eva Perez-Pampin, Dora Pascual-Salcedo, Universitat de Barcelona, Instituto de Salud Carlos III, European Commission, [Montes,A, Perez-Pampin,E] Laboratorio de Investigacion 10 and Rheumatology Unit, Instituto de Investigacion Sanitaria - Hospital Clinico Universitario de Santiago, Santiago de Compostela, Spain. [Navarro-Sarabia, F, Moreira,V] Rheumatology Unit, Hospital Universitario Virgen Macarena, Sevilla, Spain. [Rodríguez de la Serna,A, Magallares,B] Rheumatology Unit, Hospital Santa Creu e San Pau, Barcelona, Spain. [Vasilopoulos,Y, Sarafidou,T] Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece. [Fernández-Nebro,A, Ordóñez,MC] Servicio de Reumatología, HRU Carlos Haya, Universidad de Málaga, Instituto de Investigación Biomédica de Málaga (IBIMA), Málaga, Spain. [Narváez,J] Department of Rheumatology, Hospital Universitario de Bellvitge, Barcelona, Spain. [Cañete,Jd] Rheumatology Unit, Hospital Clinic, Barcelona, Spain. [Marquez,A] Instituto de Parasitología y Biomedicina López-Neyra, CSIC, Granada, Spain. [Pascual-Salcedo,D] Department of Immunology, Instituto de Investigación Hospital Universitario La Paz, Hospital La Paz, Madrid, Spain. [Joven,B, Carreira,P] Department of Rheumatology, Hospital 12 de Octubre, Madrid, Spain. [Moreno-Ramos,MJ] Department of Rheumatology, Hospital Virgen de la Arrixaca, Murcia, Spain. [Caliz,R, Ferrer,NA] Rheumatology Unit, Hospital Universitario Virgen de las Nieves, Granada, Spain. [Garcia-Portales,R] Department of Rheumatology, Hospital Virgen de la Victoria, Málaga, Spain. [Blanco,FJ] Rheumatology Department, Instituto de Investigacion Biomedica-Complejo Hospitalario Universitario A Coruna, Department of Medicine, University of Santiago de Compostela, Santiago de Compostela, Spain. [Magro,C, Raya,E] Department of Rheumatology, Hospital Clínico San Cecilio, Granada, Spain. [Valor,L] Rheumatology Unit, Hospital General Universitario Gregorio Marañón, Madrid, Spain. [Alegre-Sancho,JJ] Department of Rheumatology, Hospital Doctor Peset, Valencia, Spain. [Balsa,A] Department of Rheumatology, Instituto de Investigación Hospital Universitario La Paz, Hospital Universitario La Paz, Madrid, Spain.[Martin,J] Instituto de Parasitología y Biomedicina López-Neyra, CSIC, Granada, Spain. [Plant,D] NIHR Manchester Musculoskeletal Biomedical Research Unit, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK. [Isaacs,J] Musculoskeletal Research Group, Institute of Cellular Medicine, The Medical School, Newcastle University, National Institute for Health Research Newcastle Biomedical Research Centre, Newcastle upon Tyne Hospitals NHS Foundation Trust and Newcastle University, Newcastle upon Tyne, Newcastle, UK. [Morgan,AW] Leeds Institute of Rheumatic and Musculoskeletal Medicine, St. James's University Hospital, University of Leeds, NIHR Leeds Musculoskeletal Biomedical Research Unit, Leeds Teaching Hospitals NHS Trust, Leeds, UK. [Barton,A] NIHR Manchester Musculoskeletal Biomedical Research Unit, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Arthritis Research UK-Centre for Genetics and Genomics, The University of Manchester, Manchester, UK. [Wilson,AG] University College Dublin, Dublin, Ireland. [Gómez-Reino,JJ] Laboratorio de Investigacion 10 and Rheumatology Unit, Instituto de Investigacion Sanitaria - Hospital Clinico Universitario de Santiago, Department of Medicine, University of Santiago de Compostela, Santiago de Compostela, Spain. [Gonzalez,A] Laboratorio de Investigacion 10 and Rheumatology Unit, Instituto de Investigacion Sanitaria - Hospital Clinico Universitario de Santiago, Laboratorio Investigacion 10, Hospital Clinico Universitario de Santiago, Santiago de Compostela, Spain., Funding was provided by grants PI11/01048, PI12/01909 and by RETICS Program, RD08/0075/0019 and RD12/0009/0008 (RIER) of the Instituto de Salud Carlos III (Spain) that are partially financed by the European Regional Development Fund of the European Union, UAM. Departamento de Medicina, and Instituto de Investigación Sanitaria Hospital Universitario de La Paz (IdiPAZ)