During the past years many investigators have focused on the immunological changes in sepsis disease, and great attention has been paid to the development of practicable means of immunomonitoring. Human activated protein C (Drotrecogin alfa (activated)), an important coagulation inhibitor plays a major role in regulating microvascular coagulation, inflammation and immunology. Little is known about prognostic vascular biomarkers during the time course of patients with severe sepsis.