Cyclophosphamide use in a young woman with antiphospholipid antibodies and recurrent cerebrovascular accident

We have described a 25-year-old woman with recurrent cerebral thrombosis associated with very high levels of antibodies against phospholipids. Antinuclear antibodies and clinical features of a defined connective tissue disease were absent. Treatment with plasmapheresis, prednisone, intravenous cyclophosphamide, and warfarin was accompanied by disappearance from the serum of the lupus anticoagulant and the biologic false-positive test for syphilis; IgG anticardiolipin antibodies persisted, however, and the patient had a second cerebral thrombosis. Clinical improvement ultimately occurred after the dosage of cyclophosphamide was optimized and the level of IgG anticardiolipin antibody decreased to a level lower than any that has been previously associated with thrombotic complications.