Separation of normal human bone marrow cells by counterflow centrifugal elutriation. I. Morphological analysis and subfractionation of neutrophilic granulocytes.

We have used counterflow centrifugal elutriation to separate the nucleated cells of normal human bone marrow into their major morphologically identifiable cellular components. Human bone marrow cells were separated simultaneously into the major cell types--lymphocytes, monocytes, granulocytes, and erythroid precursors. Significant concentration of bone marrow cell types could be achieved, including myeloblasts (x 25), promyelocytes (x 43), early myelocytes ( x 22), late myelocytes (x 17), metamyelocytes (x 6), eosinophils (x 40), basophils (x 55), erythroblasts (x 35), monocytes (x 40), and plasma cells (x 35). Cell loss is minimal (85% recovery of input) and random, and cell viability, as measured by trypan blue staining, is high (greater than 95%). Factors interfering with separation are also described: a low loading flow rate, the presence of an excess of mature red cells, and the absence of fetal calf serum resulted in poor cell recovery and viability. The use of heparin as the anticoagulant resulted in cell loss, decrease in cell viability, and an ineffective separation. Separation of cells from normal bone marrow by centrifugal elutriation should facilitate the study of bone marrow cell interactions and the purification of individual types of bone marrow cells.