The inactivation of antithrombin III by serum elastase in patients with surgical infections.

The relationship between serum elastase and antithrombin III was determined in septic surgical patients as a possible mechanism for intravascular thrombosis and hypercoagulability during sepsis. Eighteen patients with surgical infections and elevated white blood cell counts had their blood assayed daily for white blood cell count, serum elastase, and antithrombin III, until the patient's white blood cell count returned to normal. Antithrombin III was significantly lower (0.87%) when elastase was above the normal range (greater than 14.2 micrograms/ml). Elastase was significantly higher (30.6 micrograms/ml), when antithrombin III was less than normal. These data indicate that elevated serum elastase is associated with a significant reduction in circulating antithrombin III. Stimuli that increase serum elastase, i.e. surgery, trauma, or sepsis may promote intravascular thrombosis by the inhibition of antithrombin III at the blood-endothelial cell interface.