TF and Schnyder corneal dystrophy: The mechanisms of activation TF are 1) increased heme levels through hemolysis which induces TF expression on the surface of endothelial cells,36 2) ischemia-reperfusion injury (hypoxia/reoxygenation),74 3) increased levels of soluble CD40 ligand through activation of platelets and exposure of CD40 ligand on their surface.75 In addition, the over expression of markers of endothelial activation such as endothelial adhesion proteins (intercellular adhesion molecule-1 [ICAM-1], E selectin [ELAM-1], P selectin and vascular cell adhesion molecule-1 [VCAM-1] has been reported in SCD.76