Raphaèle Seror1, Xavier Mariette2. 1. Rheumatology Department, Research Center for Immunology of Viral Infections and Autoimmune Diseases (ImVA), Assistance Publique-Hôpitaux de Paris, Hôpitaux Universitaires Paris-Sud, Université Paris-Sud, INSERM U1184, Le Kremlin Bicêtre 94270, France. Electronic address: raphaele.seror@aphp.fr. 2. Rheumatology Department, Research Center for Immunology of Viral Infections and Autoimmune Diseases (ImVA), Assistance Publique-Hôpitaux de Paris, Hôpitaux Universitaires Paris-Sud, Université Paris-Sud, INSERM U1184, Le Kremlin Bicêtre 94270, France.