Effects of viral activation of the vessel wall on inflammation and thrombosis.

Herpes simplex virus type 1 and cytomegalovirus alter the phenotype of the endothelium in vitro from anticoagulant to procoagulant, thereby promoting the adherence of neutrophils and platelets to the endothelium. Virus infection of the endothelium induces the expression of viral glycoproteins and adhesion molecules, which promote neutrophil and monocyte adhesion. Herpes simplex infection of the endothelium promotes prothrombinase assembly, allowing more efficient thrombin generation. Excess thrombin generation causes translocation of P-selectin. Viral infection also induces the procoagulant molecule, tissue factor, in endothelial cells. These enhanced procoagulant effects are associated with the loss of anticoagulants, including thrombomodulin, prostacyclin and tissue plasminogen activator. These studies support the speculation that virus infection in vivo promotes vascular injury and thrombosis, which may contribute to disease states such as atherosclerosis.