High granulocyte yield with a simple method of filtration leukapheresis.

A simple continuous filtration leukapheresis has been devised whereby two Leuko-Pak filters can be charged and eluted within 5 h with approximately 121 of blood in a closed system of tubes. Blood flows by means of gravity without the use of pumps. Without premedication with prednisolone the average yield from 10 donors was 3.66 x 10(10) granulocytes per leukapheresis and after premedication with 150 mg prednisolone orally it was 6.44 x 10(10) granulocytes per leukapheresis. The in vitro function of filter granulocytes was not reduced even after premedication with prednisolone. In comparison with leukapheresis by blood cell separators this modified method of filtration leukapheresis offers the following advantages: 1) the granulocyte yield per litre of whole blood processes is higher, 2) technical assistants in a blood-bank can carry out the method on several donors simultaneously, 3) the method is more economical than leukapheresis by blood cell separators.