Julien Paccou1,2, Bernard Cortet3,4. 1. Department of Rheumatology, Lille University Hospital, Lille, France. julien.paccou@chru-lille.fr. 2. Lille University-ULCO, PMOI, EA 4490, 59000, Lille, France. julien.paccou@chru-lille.fr. 3. Department of Rheumatology, Lille University Hospital, Lille, France. 4. Lille University-ULCO, PMOI, EA 4490, 59000, Lille, France.