Cell size monitored counterflow centrifugation of human bone marrow resulting in clonogenic cell fractions substantially depleted of small lymphocytes

Abstract

Human bone marrow cells were fractionated by physical methods in order to obtain cell fractions enriched in clonogenic cells and devoid of immunocompetent lymphocytes. The bulk of the erythrocytes was removed by isopycnic gradient centrifugation on Ficoll-Isopaque (d = 1.085 g/ml) and the majority of mature granulocytes on Percoll (d = 1.070 g/ml). The nucleated cells were separated into fractions by counterflow centrifugation. Continuous monitoring of the effluent of the elutriator by a light scatter device improved the reproducibility of the separation profiles. Progenitor cells did not form a single distinct peak and the maximal enrichment factor was 8.5. Lymphocytes were eliminated almost completely from the progenitor cell rich fraction (both CFU-GM and BFU-E). Physical elimination of lymphocytes from human bone marrow may offer an alternative approach to the prevention of graft-versus-host disease in allogeneic bone marrow transplantation.