Serial measurements of a plasma prostacyclin inhibitor in a patient with recurrent abortions and lupus anticoagulant; a case report.

Defective plasmatic stimulation of prostacyclin (PGI2) production by vascular cells has been described in patients with lupus anticoagulant (LAC). A young woman with recurrent abortions, LAC and evidence for deficient PGI2 production was studied. Serial measurements of a plasma PGI2 inhibitor, LAC and anticardiolipin antibodies (ACA) have been performed before and throughout her fourth pregnancy. Antenatal care and treatment with prednisone and heparin started at 10 weeks gestation. The plasma of our patient continued to inhibit PGI2 production by vascular cells despite treatment. The presence of inhibitor(s) of PGI2 release was confirmed by mixing the patient's plasma with normal plasma. In addition, an IgM lupus anticoagulant fraction (but not the IgG fraction) interfered with the release of arachidonic acid in human endothelial cells induced by thrombin. Despite prednisone and heparin treatment we did not find a complete correction of the LAC activity and the ACA (IgM type) still remained positive before the detection of a fetal death at 26 weeks. The placenta showed abundant infarcts and areas of ischaemic necrosis. We suggest that the defect in vascular PGI2 release could compromise fetal outcome.