- Pseudo gray platelet syndrome
Pseudo gray platelet syndrome was described by Cockbill, Burmester, and Heptinstall (1988) who reported a 25-year-old woman with a history of mild bruising and bleeding. Bleeding time, activated partial
thromboplastin time,prothrombin time, andeuglobulin lysis time were within normal limits. There were noplatelet antibodies detected. The patient's mother and two sisters had histories of easy bruising and heavy menstrual periods. A brother had no reported bleeding tendencies. Platelets from the mother, sisters, and a daughter were normal in number and appearance under the light microscope. Platelets in blood collected intoEDTA tubes appeared gray and agranular compared with platelets from blood incitrate orheparin . The key finding is underelectron microscopy , EDTA-exposed platelets showed extensive activation, with loss of storage granule contents and pseudopod formation. Platelet aggregation studies were normal.The abnormal platelet reaction following EDTA exposure is thought to be caused by a
plasma factor , although not animmunoglobulin . The mechanism by which platelet activation occurs remains unknown. Few cases have been reported in the literature.Pseudo-gray platelet syndrome differs from
gray platelet syndrome (GPS), one of thegiant platelet syndrome s. GPS is characterized bythrombocytopenia , abnormally large agranular platelets in peripheral blood smears, and almost total absence ofplatelet alpha-granule s and their constituents. The defect in GPS is the failure ofmegakaryocyte s to package secretory proteins into alpha-granules. Patients with the GPS are affected by mild to moderate bleeding tendencies.References
*Cockbill, S.R., Burmester, H.B.C., and S. Heptinstall. Pseudo-gray platelet syndrome-Gray platelets due to degranulation in blood collected into EDTA. European Journal of Haematology 41:326-333 (1988).
*Jantunen, Esa. Inherited giant platelet disorders. European Journal of Haematology 53:191-196 (1994).
*Jantunen, E., Hanninen, A., Naukkarinen, A., Vornanen, M., and R. Lahtinen. Gray platelet syndrome with splenomegaly and signs of extramedullary hematopoiesis: a case report with review of the literature. American Journal of Hematology 46:218-224 (1994).
*E.J. Wills . Gray Platelet Syndrome. Ultrastructural Pathology 13:451-455 (1989).
Wikimedia Foundation. 2010.