Platelet phospholipids in thrombocytosis due to myeloproliferative disorders

Platelet phospholipids were analyzed in patients with thrombocytosis due to myeloproliferative disorders and secondary thrombocytosis. A significant increase of phosphatidylcholine together with a decrease of sphingomyelin was observed in each of the 8 patients with primary thrombocythaemia and in each of the 5 patients with excessive thrombocytosis due to primary polycythaemia. The phospholipid pattern of the 3 patients with secondary thrombocytosis did not differ from that of the normal controls. This marked difference in the platelet phospholipids may be helpful in distinguishing secondary thrombocytosis persisting for a prolonged period of time after splenectomy from previously unrecognized primary thrombocythaemia unmasked by splenectomy. The decreased sphingomyelin/lecithin ratio of platelets in primary thrombocythaemia may interfere with platelet function by increasing the fluidity of their membrane.