PLATELET ACTIVATION AND PLATELET-ERYTHROCYTE AGGREGATES IN PATIENTS WITH SICKLE-CELL-ANEMIA

Vascular occlusion and vasculopathy underlie much of the morbidity in patients with sickle cell anemia, Platelets may play a role in this va sculopathy, Samples from 12 adult patients with sickle cell anemia wer e examined for evidence of platelet activation and formation of platel et-erythrocyte aggregates (PEA) using fluorescent-labeled monoclonal a ntibodies and flow cytometry. We noted an increased expression of acti vation-dependent antigens on the platelets from patients with sickle c ell anemia compared with those from both white and black control subje cts, In addition, patients with sickle cell anemia had increased level s of platelet microparticles and PEA. Platelets are activated in patie nts with sickle cell anemia and they adhere to sickle erythrocytes. Th e significance of this activation and adherence are the subject of fur ther investigation.