Granulocyte harvest for transfusion: donor response to repeated leukapheresis

Leukapheresis of normal donors with the NCI-IBM Continuous Flow Blood Cell Separator was compared with the method of filtration leukapheresis. An average of 5.7 times 10-9 (range 1.4 to 10.9 times 10-9) granulocytes were collected on 25 occasions with the blood cell separator compared with an average of 36.6 times 10-9 (range 20.1 to 61.3 times 10-9) obtained by filtration leukapheresis on 85 occasions. Donor platelet counts decreased following donation by an average of 29,000/mul (14%) with continuous flow centrifugation (CFC) and an average of 40,000/mul (17%) with filtration leukapheresis (FL). Estimated donor packed red blood cell loss, including blood obtained for investigative purposes, was 80 ml per donation with CFC and 67 ml per donation when FL was used. FL resulted in at least a 25 per cent increase in the granulocyte count of donors by donation completion in 61 per cent of donors, although postdonation granulocytosis did not correlate with increased cell harvest. CFC donors generally displayed a postdonation decrease in granulocyte count. Normal numbers of granulocytes were maintained in donors undergoing frequent leukapheresis and no donor's health was compromised by the removal of large numbers of granulocytes. Repeated donations were possible with both systems. Although platelet counts dropped more with FL, the procedure was performed as frequently as eight times in a ten-day period without development of severe donor thrombocytopenia. Donor red blood cell loss appears to be the limiting factor in the repeated use of either system. Blood loss could be significantly decreased under routine conditions if fewer samples were obtained for investigational purposes. Filtration leukapheresis offers the advantage of significantly greater granulocyte yields than is possible with CFC unless modifications such as arterio-venous shunts or the use of steroids and/or rouleaux-inducing agents are employed.