Collection of large quantities of mononuclear cells from individual donors by continuous flow centrifugation leukapheresis.

Continuous flow centrifugation leukapheresis allows the continuous removal of leukocytes from the peripheral blood of individual donors. With the IBM 2997 cell separator, leukapheresis of granulocytes has been well established. On the other hand, no standard procedure for the collection of lymphocytes and/or monocytes has yet been described. Here, we investigated the conditions necessary for collection of large amounts of mononuclear cells with highest possible purity. The average yield from more than 100 healthy donors was 8 X 10(9) leukocytes per donor containing 80-100% mononuclear cells (MNC). Of the MNC, 10-55% were monocytes and 45-90% lymphocytes, depending on the donor. The rotor speed for maximal MNC collection was between 800 and 1000 rpm. Highest yields of monocytes were obtained at 900 rpm. No sedimenting agents were added to the blood. With more than 150 donors no rebound leukocytosis or lasting depression of blood cell counts was observed after leukapheresis. One patient with the Sézary syndrome who was subjected to leukapheresis for 26 months at 3-6 week intervals showed no pathological changes in his blood cell count to date. The disease was stabilized and no abnormalities in resistance to infection became apparent.