IRCCS Istituto Giannina Gaslini - Paediatric Rheumatology International Trials Organisation (PRINTO), IRCCS Istituto Giannina Gaslini, IRCCS Istituto Giannina Gaslini, IRCCS Istituto Giannina Gaslini, Utrecht University - Wilhelmina Children’s Hospital, Sanjay Gandhi Post Graduate Institute of Medical Sciences - Department of Clinical Immunology and Rheumatology, King Faisal Specialist Hospital and Research Centre, IRCCS Istituto Giannina Gaslini, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Western University Children’s Hospital, University of Oslo, University Hospital Münster, Hospital Sor Maria Ludovica, Hospital Sor Maria Ludovica, Cincinnati Children's Hospital Medical Center, IRCCS Istituto Giannina Gaslini, University of Calgary - Alberta Children's Hospital, Sofiamed, Juliane Marie Centret, National Institute of Rheumatology and Physiotherapy, University of Latvia, Universidade Estadual Paulista, Tehran University of Medical Sciences - Dr. Shariati Hospital, Institute of Rheumatology of Belgrade, Thessaloniki University, Utrecht University - Wilhelmina Children’s Hospital, IRCCS Istituto Giannina Gaslini, IRCCS Istituto Giannina Gaslini, IRCCS Istituto Giannina Gaslini and Independent