Antiphospholipid antibodies: anticardiolipin and the lupus anticoagulant in systemic lupus erythematosus (SLE) and in non-SLE disorders. Prevalence and clinical significance.

To determine the prevalence of lupus anticoagulant and anticardiolipin in systemic lupus erythematosus (SLE) and in non-SLE disorders, and to evaluate the clinical significance of these autoantibodies as they relate to thromboembolic events, neuropsychiatric disorders, thrombocytopenia, and fetal loss. A computer-assisted search of the literature (MEDLINE, 1966 to 1989) and review of the bibliographies of all identified articles. Series of ten or more subjects were included if the assays used for detecting lupus anticoagulant or anticardiolipin met the specified minimal criteria for validity. Series were categorized according to antibody type and underlying disease. A systematic appraisal of patient selection methods, study design, and assay methods was done. An analysis of 29 published series (comprising over 1000 patients with SLE) yielded an average frequency of 34% for the lupus anticoagulant and 44% for anticardiolipin. Antiphospholipid antibodies are also prevalent in patients with various non-SLE disorders. In patients with SLE, a statistically significant association exists between the presence of either antibody and a history of thrombosis, neurologic disorders, or thrombocytopenia. The available data suggest, but do not firmly support, an association between antiphospholipid antibodies and history of fetal loss in women with SLE. Contrary to prevailing opinion, none of these associations have been shown conclusively in patients with non-SLE disorders. The results of predominantly retrospective series suggest that for certain persons (patients with SLE or closely related disorders) antiphospholipid antibodies may be important risk factors for thrombosis, neurologic disease, thrombocytopenia, and fetal loss. Standardized tests for lupus anticoagulant and anticardiolipin, as well as long-term, prospective clinical studies, are needed to determine the prognostic value of antiphospholipid antibodies.