SEPARATION OF CHEMOTHERAPY PLUS G-CSF-MOBILIZED PERIPHERAL-BLOOD MONONUCLEAR-CELLS BY COUNTERFLOW CENTRIFUGAL ELUTRIATION - IN-VITRO CHARACTERIZATION OF 2 DIFFERENT CD34(-POPULATIONS() CELL)

Counterflow centrifugal elutriation (CCE) has been extensively employe d in T cell depletion of bone marrow cells for allografting. Neverthel ess very little is known about CCE properties of mobilized hematopoiet ic progenitors. In this study five leukapheresis products collected af ter chemotherapy and G-CSF from patients with non-Hodgkin's lymphoma w ere elutriated. Two mononuclear cell fractions were obtained containin g smaller and less dense cells (lymphocyte fraction) and larger and de nser cells (monocyte fraction), respectively, The presence of immature CD34(+) progenitor cells, not co-expressing CD33, CD38 and HLA-DR ant igens, was demonstrated in both cell fractions, CD34(+) cells were iso lated from each fraction and grown in various culture conditions (CPU- GM and BFU-E assay, blast cell colony assay, cytokine supplemented liq uid culture), CD34(+) cells isolated from the monocyte fraction showed a longer lasting expansion in liquid culture and a higher number of b last cell colonies than CD34(+) cells selected from the lymphocyte fra ction, Moreover a significant reduction of T cell number was obtained in the monocyte fraction, These data suggest that chemotherapy plus G- CSF-mobilized progenitor cells show a characteristic behavior when sub jected to CCE, allowing an efficient T cell depletion without losing m ore immature progenitors.