Rapid isolation of mononuclear cells from buffy coats prepared by a new blood cell separator.

A newly developed cell separator for the preparation and fractionation of buffy coat cells from human peripheral blood is described. In this cell separator buffy coats (BC-1) as routinely obtained from blood banks were used for the preparation of a second buffy coat (BC-2) with a volume of only 5-6 ml. A special fractionation device allowed sterile isolation of almost pure platelets and mononuclear cells with recoveries of 75 +/- 10% and 89 +/- 4% respectively. The white blood cell contamination of the platelet suspension never exceeded 20 X 10(6) leukocytes (i.e., less than 1 leukocyte per 5000 platelets). Furthermore, the mononuclear cell suspensions were shown to be contaminated with only 3 +/- 2% granulocytes, whereas the white blood cell/red blood cell ratio was 2.6 +/- 1.6, so that they could therefore be directly used for further separation by means of centrifugal elutriation. These results indicate that this cell separator provides a rapid (+/- 1 h) isolation of both platelets and mononuclear cells without exposing the buffy coat cells to foreign substances like Ficoll or Percoll.