Improvement of platelet function following plateletpheresis in patients with myeloproliferative diseases.

Four patients with myeloproliferative diseases and acute hemorrhagic or thrombotic complications of thrombocytosis were treated with plateletpheresis by discontinuous-flow centrifugation. Reduction of platelet counts was achieved rapidly, without complications and was associated with clinical improvement. In all four cases, abnormal platelet aggregation testing was present before pheresis, but improved immediately after pheresis. Platelet-sizing data obtained in one case suggested that during the pheresis procedure, a population of larger volume platelets was selectively removed. The efficacy of plateletpheresis in these clinical situations may be related to the selective removal of a large abnormal platelet population.