Apheresis-induced platelet activation:: comparison of three types of cell separators

BACKGROUND: Platelet-harvesting technology differs in various cell separators. Alteration in shear stress and biocompatibility of surfaces may give variable platelet activation and thereby affect the quality of the component. STUDY DESIGN AND METHODS: Four groups (n = 10) of single-needle apheresis procedures using three cell separators, were compared: 1) Spectra LRS, 90-minute harvesting time; 2) MCS+, 90-minute harvest; 3) Amicus, 90-minute; and 4) Amicus, 45-minute. Whole-blood samples were collected from the donors as were samples from the final components at intervals during the first 4 hours after cessation of the apheresis. Platelet activation status and platelet activation capacity after agonist stimulation were assessed by flow cytometry. RESULTS: No activated platelets were found in preapheresis and postapheresis samples from the donors. The platelets in the components from the Amicus (90-min) were significantly more activated than those in the other groups of components: that is, there was increased size of platelet aggregates, increased fraction of microparticles, increased degranulation, increased fibrinogen receptor activation, and decreased von Willebrand factor receptor expression. Moreover, the response of these platelets to agonist stimulation was reduced for all activation variables. CONCLUSIONS: After 90 minutes' processing time, platelets obtained with the Amicus cell separator were significantly more activated than platelets harvested with the Spectra and the MCS+.