Disorders of hemostatic function in patients with systemic lupus erythematosus.

A wide spectrum of hemostatic abnormalities is found in patients with SLE. Thrombocytopenia and qualitative platelet disorder (impaired aggregation to collagen) are probably both due to antiplatelet antibodies, which can be found in most patients with the disease. About 10% of patients with SLE have a circulating anticoagulant. These circulating anticoagulants are broadly heterogeneous. Although most reported cases act at the level of the prothrombin converting complex, 15 of the 74 cases here reviewed had other points of action. The anticoagulants are probably all antibodies; they differ (with rare exceptions) from other naturally occurring circulating anticoagulants in having an immediate rather than a progressive effect, and in acting, not against pre-existing procoagulants, but against unstable complexes. An anticoagulant of the type found in SLE is only rarely observed in the absence of SLE; its presence in a patient is thus of some diagnostic importance. Hypoprothrombinemia is a common second lesion in patients with circulating anticoagulants. Its pathogenesis is obscure. Two patients with acquired von Willebrand's disease have been observed. All the hemostatic abnormalities found in SLE probably have immunologic bases; all respond to glucocorticoid treatment.