Abstract
Following allogeneic hematopoietic stem cell transplantation (HSCT) patients may have an increased bleeding tendency in spite of a normal platelet count. Moreover, an association between chronic graft-versus-host disease (cGVHD) and a thrombophilic state has been observed. Platelet receptors and granules from 27 patients following HSCT (13 without cGVHD, 14 with cGVHD) were evaluated by flow ...
Abstract
Following allogeneic hematopoietic stem cell transplantation (HSCT) patients may have an increased bleeding tendency in spite of a normal platelet count. Moreover, an association between chronic graft-versus-host disease (cGVHD) and a thrombophilic state has been observed. Platelet receptors and granules from 27 patients following HSCT (13 without cGVHD, 14 with cGVHD) were evaluated by flow cytometric analysis and compared to 62 healthy controls. Platelets from HSCT patients stained weakly with mepacrine indicating a reduced content of dense bodies, whereas no significant degranulation reaction of alpha granules and lysosomes was detectable. In addition, a lower surface expression of GP Ia/IIa was observed, indicating an acquired thrombocytopathy. The surface receptors are activated in HSCT patients, which could be seen by the lower surface expression of GP Ib internalized during the activation process and elevated levels of LIBS-1 and PAC-1 antibody binding. Patients with cGVHD had a seven-fold increased ratio of microparticles. This study demonstrates platelet receptor and granule defects in patients following HSCT. The key role of platelets in HSCT-associated hemostatic disorders is underscored by the high levels of circulating microparticles in cGvHD patients which might explain the thrombophilic state in these patients.
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