Seronegative antiphospholipid syndrome associated with plasminogen activator inhibitor.

Antiphospholipid syndrome is characterized by thrombosis, recurrent fetal loss, thrombocytopenia and is associated with the presence of antiphospholipid antibodies, especially anticardiolipin antibodies. We present a patient with the clinical features of antiphospholipid syndrome, namely recurrent venous and arterial thrombosis, recurrent abortions, thrombocytopenia and libido reticularis but with persistently negative serology for any type of antiphospholipid antibody. The possible existence of 'seronegative' antiphospholipid syndrome is proposed. Of additional interest in this patient is the presence of significantly elevated levels of plasminogen activator inhibitor. The role of this inhibitor, if any, in the antiphospholipid syndrome and/or seronegative antiphospholipid syndrome is not known and merits further study.