 - Endothelial Microparticles Platelet free plasma PFP will be prepared by a double step centrifugation of citrated blood at 1,500g for 15 min and 13,000 g for 2 min at room temperature. Then EMP will be enumerated by flow cytometry after labelling of PFP using monoclonal antibodies directed against endothelial antigens, such as CD144 19. To investigate the proportion of EMP within the whole circulating MP, MP for platelet, leukocyte and erythrocyte origins will be determined using respectively, CD41, CD45, Glycophorin-directed antibodies, and the total number of phosphatidylserine expressing MP will be determined using AnnexinV binding. 