Correction of thrombocytopenia with small dose aspirin in the primary antiphospholipid syndrome.

We describe 2 patients with primary antiphospholipid syndrome in whom thrombocytopenia, which had not responded to high dose prednisone treatment, was promptly corrected after they started taking small doses (100 mg/day) of aspirin. This effect has been sustained despite subsequent prednisone withdrawal. Theoretical reasons for such an apparent therapeutic effect of aspirin in these patients are discussed.