1. Systemic Autoimmune Diseases Unit, Department of Medicine, IDIBAPS (Institut d'Investigacions Biomèdiques “August Pi i Sunyer’), Hospital Clinic, University of Barcelona, Barcelona, Catalonia, Spain; Unitat de Malalties Autoimmunes Sistèmiques, Hospital Clinic, C/Villarroel, 170, 08036-Barcelona, Catalonia, Spain, Tel: (+ 34) 93 2275774; Fax: (+ 34) 93 2275774;
2. Systemic Autoimmune Diseases Unit, Department of Medicine, IDIBAPS (Institut d'Investigacions Biomèdiques “August Pi i Sunyer’), Hospital Clinic, University of Barcelona, Barcelona, Catalonia, Spain
3. Rheumatology Unit, School of Medicine, Benemérita Universidad Autonoma de Puebla, Puebla, Mèxico
4. Rheumatology Unit, Hospital de la Vila-Joiosa, Alicante, Spain
5. Department of Internal Medicine, Hospital Son Dureta, Mallorca, Spain