GRANULOCYTE-COLONY-STIMULATING FACTOR-INDUCED COMOBILIZATION OF CD4(-)CD8(-) T-CELLS AND HEMATOPOIETIC PROGENITOR CELLS (CD34(+)) IN THE BLOOD OF NORMAL DONORS

The feasibility of transplantation of HLA-matched hematopoietic progen itor cells from the blood of normal donors given granulocyte colony-st imulating factor (G-CSF) has been reported recently. In the current st udy, the changes in T-cell subsets as well as CD34(+) cells were deter mined in one blood volume leukapheresis products of six normal individ uals given G-CSF, Examination of the T-cell subsets in the leukapheres is products showed three different patterns: one in which a discrete p opulation of CD4(-)CD8(-) alpha beta T cells was found in addition to the typical CD4(+) and CD8(+) T cells in the unfractionated as well as in high- and low-density cells; a second in which the discrete popula tion of CD4(-)CD8(-) alpha beta T cells was predominant only in the lo w-density fractions; and a third in which a discrete population of CD4 (-)CD8(-) T cells was not observed. The median yield of CD4(-)CD8(-) T cells was about fourfold to fivefold higher than the calculated numbe r present in one blood volume (5L) from normal individuals. The ratios of CD34(+) cells to CD4(+) and CD8(+) T cells, and of CD4(-)CD8(-) T cells to CD4(+) and CD8(+) T cells, were highest in the low-density fr actions. These fractions suppressed the mixed leukocyte, and may ameli orate graft-versus-host disease as compared with unfractionated cells. (C) 1997 by The American Society of Hematology.