1. University Department PROMISE “G. D’Alessandro”, University of Palermo, Via del Vespro 129, 90100 Palermo, Italy
2. Paediatric Rheumatology, UOC of Paediatrics, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138 Bologna, Italy
3. Paediatric Unit, Department of Health Science, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy
4. Paediatric Rheumatology and Immunology, Vito Fazzi Hospital, 73100 Lecce, Italy