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

BACKGROUND: Platelet-harvesting technology differs in various cell separato rs. Alteration in shear stress and biocompatibility of surfaces may give va riable platelet activation and thereby affect the quality of the component. STUDY DESIGN AND METHODS: Four groups (n = 10) of single-needle apheresis p rocedures using three cell separators, were compared: 1) Spectra LRS, 90-mi nute harvesting time; 2) MCS+, 90-minute harvest; 3) Amicus, 90-minute; and 4) Amicus, 45-minute. Whole-blood samples were collected from the donors a s were samples from the final components at intervals during the first 4 ho urs after cessation of the apheresis. Platelet activation status and platel et activation capacity after agonist stimulation were assessed by flow cyto metry. RESULTS: No activated platelets were found in preapheresis and postapheresi s samples from the donors. The platelets in the components from the Amicus (90-min) were significantly more activated than those in the other groups o f components: that is, there was increased size of platelet aggregates, inc reased fraction of microparticles, increased degranulation, increased fibri nogen receptor activation, and decreased von Willebrand factor receptor exp ression. Moreover, the response of these platelets to agonist stimulation w as reduced for all activation variables. CONCLUSIONS: After 90 minutes' processing time, platelets obtained with the Amicus cell separator were significantly more activated than platelets har vested with the Spectra and the MCS+.