[1] Univ Barcelona, Paediat Rheumatol Unit, Hosp St Joan de Deu, Esplugues, Spain
[2] Hosp Univ & Politecn, Paediat Rheumatol Unit, Valencia, Spain
[3] Hosp Meixoeiro, Dept Internal Med, Vigo, Spain
[4] Hosp Ramon & Cajal, Dept Paediat Rheumatol, Madrid, Spain
[5] Hosp La Paz, Dept Paediat Rheumatol, Madrid, Spain
[6] Hosp Univ Cent Asturias, Dept Paediat, Oviedo, Spain
[7] Hosp Univ San Cecilio, Dept Paediat, Granada, Spain
[8] Hosp Vinaros, Dept Internal Med, Vinaros, Spain
[9] Corp Sanitaria Parc Tauli, Dept Paediat, Sabadell, Spain
[10] Hosp Clin Barcelona, IDIBAPS, Dept Immunol CDB, Barcelona, Spain