Buffy coat and cell separator granulocyte concentrates. Comparison of cell content and in vitro granulocyte function

Buffy coat granulocyte concentrates were prepared manually from single fresh whole blood donations after centrifugation. The erythrocyte, granulocyte and platelet numbers in these concentrates were compared to cell numbers in concentrates obtained by mechanical leukapheresis using intermittent flow centrifugation. Buffy coats contained approximately half the number of granulocytes and three times the number of erythrocytes per unit volume than cell separator concentrates. There was no difference in platelet numbers. Thus to give a therapeutic dose of granulocytes equivalent to that obtained by cell separation, 2-3 times greater volume of buffy coat concentrates would be required. In vitro granulocyte function, as measured by migration, phagocytosis, and Candida killing was also compared in buffy coat and cell separator concentrates. The only difference found was reduced Candida killing in the buffy coat granulocytes. The possible clinical use of buffy coat concentrates, as a source of granulocytes, is discussed.