In Japan, most platelet concentrates (PC) are presently collected by plateletpheresis machines and suspended in autologous plasma. Transfusion of PC occasionally induces non-hemolytic side reactions in thrombocytopenic patients by unknown factors in plasma. To prevent these side effects, removal of autologous plasma from PC has been used with a synthetic medium used for resuspension of platelets. In this study, we compared two methods for washing platelet concentrates (WPC), one by centrifugation to a platelet pellet (P-WPC) and the other using a plateletpheresis machine (CS3000 plus) to non-pelleted platelets (CS-WPC). Both these methods allowed removal of nearly all plasma in PC. Platelet recovery with CS-WPC (98.56%) was greater than that with P-WPC (91.07%). LDH release into the supernatant was lower with CS-WPC than with P-WPC. Platelet discoid ratio and ADP/collagen aggregation in CS-WPC were also greater than those with P-WPC. However, other indicators such as pH, pCO2, PO2, MPV, %HSR, P-selectin release and lactate concentration in the supernatant were not significantly different between the two methods. These results suggest that this new washing method with the CS3000 plus plateletpheresis machine is useful for the preparation of WPC with an acceptable quality of platelets.
