[1] Univ Hosp Southampton NHS Fdn Trust, NIHR Wellcome Trust Clin Res Facil, Southampton, Hants, England
[2] Yeovil Dist Hosp, Dept Rheumatol, Yeovil BA21 4AT, England
[3] Univ Southampton, Southampton Gen Hosp, Lifecourse Epidemiol Unit, MRC, Southampton, Hants, England
[4] Hosp Univ Severo Ochoa, Madrid, Spain
[5] Hop Ambroise Pare, AP HP, Dept Rheumatol, Boulogne, France
[6] Univ Versailles St Quentin, Lab Excellence INFLAMEX, INSERM, U1173, Montigny Le Bretonneux, France
[7] Univ Amsterdam, Acad Med Ctr Amsterdam, Amsterdam, Netherlands
[8] Brest Univ Med Sch Hosp, Brest, France
[9] Inst Gaslini, Genoa, Italy
[10] Univ Genoa, Dept Pediat, Genoa, Italy
[11] Hosp Gen Univ Gregorio Maranon, Dept Rheumatol, Madrid, Spain
[12] Rigshosp, Ctr Rheumatol & Spine Dis, Copenhagen Ctr Arthrit Res, Glostrup, Denmark
[13] Univ Copenhagen, Dept Clin Med, Copenhagen, Denmark
[14] Queens Univ Belfast, Belfast, Antrim, North Ireland
[15] Pediat Rheumatol Res Inst, Bad Bramstedt, Germany
[16] Emma Childrens Hosp, Acad Med Ctr, Amsterdam, Netherlands
[17] Reade, Jan van Breemen Res Inst, Dept Rheumatol, Amsterdam, Netherlands
[18] Univ Nis, Ctr Clin, Dept Pediat Rheumatol, Fac Med, Nish, Serbia
[19] Univ Leeds, Leeds Inst Rheumat & Musculoskeletal Med, NIHR Leeds Musculoskeletal Biomed Res Unit, Leeds, W Yorkshire, England