The lupus anticoagulant.

The clinical and laboratory experience with the lupus anticoagulant was reviewed in 37 patients. The anti-coagulant is thought to act by blocking the activation of prothrombin by the prothrombin activator comlex of factors Xa, V, and phospholipid. Although the anticoagulant has been principally associated with diseases of immune origin, 14 of the present patients had disorders not thought to be immune in nature. Eighteen patients underwent twenty-one operative procedures with only a single episode of excessive bleeding. In the author's experience, the lupus anticoagulant is a rare cause of bleeding.