Thrombosis in systemic lupus erythematosus. Relation to the presence of circulating anticoagulants.

In an earlier report on the kidney in systemic lupus erythematosus (SLE), we described a subset of patients with circulating anticoagulants; many had glomerular and arteriolar thrombosis in the absence of necrosis and subendothelial deposits. The present study extends these observations to a larger group of patients with SLE and a circulating anticoagulant, and compares its findings with those in patients with SLE without evidence of an anticoagulant. It demonstrates (1) a higher prevalence of clinically recognizable thrombotic events in the venous and arterial circulations in patients with SLE and a detectable anticoagulant; (2) a probable shortening in life span; (3) a higher prevalence of glomerular thrombi; (4) elevated levels of factor VIII antigen and von Willebrand factor; and (5) significantly lower platelet counts and decreased in vitro platelet aggregation in response to adenosine diphosphate, epinephrine, and collagen. Since prednisone treatment often results in improvement or disappearance of a prolonged partial thromboplastin time, the test most commonly used for screening of a circulating anticoagulant, we suggest that the prevalence of this abnormality may be underestimated in patients with SLE.