Pilot Study Related to the Effect of Clopidogrel on Plasmatic Soluble CD40 Ligand During Systemic Lupus Erythematous

Type I interferon (IFN) and CD40L have been identified as important in SLE pathogenesis (1). CD40L is now considered as a biomarker of lupus activity (4). Because platelets represent a major reservoir of CD40L, we previously studied the role of platelet derived CD40L in SLE pathogenesis (5). We showed that platelets from SLE patients were activated in vivo by circulating immune complexes composed of autoantibodies bound to self antigens through a Fc-gamma Receptor IIa (CD32)-dependent mechanism. Further, platelet activation correlated with severity of the disease and activated platelets formed aggregates with antigen-presenting cells including monocytes and plasmacytoid dendritic cells. In addition, activated platelets enhanced IFN-α secretion by immune complexes-stimulated plasmacytoid dendritic cells in vitro through a CD154-CD40 interaction. In lupus prone mice, depletion of platelets or administration of the clopidogrel improved all measures of disease activity and overall survival. In this pilot study the treatment of the research is clopidogrel given at the dose of 75mg once a day. For the features of the treatment, its contraindications, its disruption in case of side effects cf to annex 1. Clopidogrel associated with the usual treatment of patients will be given for 12 weeks, the follow up of patients will be 16 weeks, all side effects occurring during this period will be recorded.