Plateletpheresis by Discontinuous Centrifugation: Effect of Collecting Methods on the in Vitro Function of Platelets

Abstract

The in vitro function of [human] platelets collected by 2 different methods during centrifugal plateletpheresis was compared. The RBC [red blood cell] method involves collecting platelets with red cells followed by a supplementary spin to remove them. The no-RBC method requires collecting platelets only from the buffy coat without red cells. The platelet response to ADP, epinephrine and collagen was slightly reduced in platelet-rich plasma (PRP) prepared by the no-RBC technique and was markedly decreased in samples obtained by the RBC technique when compared to prepheresis controls. The decrease in platelet response to ADP, epinephrine and collagen was apparent in 3 testing systems: aggregation, release of serotonin and reptilase clot retraction. Plasma and platelets appeared to be affected by the pheresis procedure. Platelet preparations obtained by the RBC and the no-RBC techniques showed an increase of platelet factor 3 activity and an enhancement of aggregation, release of serotonin and clot retraction induced by thrombin as compared to prepheresis controls. Postpheresis platelet-poor plasma contains platelet membrane fragments which exhibit a high platelet factor 3 activity. The RBC method, although providing a higher platelet yield, caused more qualitative alterations in platelets than in thcse obtained by the no-RBC method. Both methods of collecting platelets activated the procoagulant activity of platelets.