Pheresis with the IBM 2997

We have used the NCI‐IBM 2997 cell separator in 85 leukapheresis and 34 plateletpheresis procedures. Using hydroxyethyl starch (HES)and steroid pretreatment, our mean granulocyte yield was 19.3 billion cells in a mean product volume of 270.5 ml, containing 10.6 ml of red blood cells. The mean platelet yield during leukapheresis was 18.5 × 1010, as compared with 37.2 × 1010 when plateletpheresis alone was performed. There was a strong correlation between the mean level of granulocytes in the blood before leukapheresis and the granulocyte yield in the product. Other variables well‐correlated with granulocyte yield were the red blood cells in the product, the total blood volume processed, and the product volume. Platelets obtained during plateletpheresis were significantly correlated with the total blood volume processed and with the volume of red blood cells in the product. Donor reactions were no more frequent with the IBM 2997 than with other pheresis systems. This appears to be the system that can provide the best granulocyte yields at the present time.