Circulating microparticles of PNH patients express endothelial markers: intercellular adhesion molecule 1 (ICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), von Willebrand factor, CD144 (VE-cadherin), indicating chronic endothelial activation and vascular inflammation.33,34 Eculizumab (a monoclonal antibody to complement protein 5) therapy results in rapid and sustained decreases in markers of inflammation, thrombin generation, and TF-bearing microparticles in PNH patients.35 The gene discussed is VWF; the disease is paroxysmal nocturnal hemoglobinuria.