CD34 PROGENITOR-CELL SUBSET ANALYSES IN NORMAL HUMAN BONE-MARROW AND MARROW HARVESTED AFTER INTERMEDIATE-DOSE CHEMOTHERAPY

Previous attempts to characterize harvested marrow and peripheral bloo d stem cell (PBSC) in order to predict time to and quality of engraftm ent post autologous bone marrow transplant (autoBMT) have included use of in vitro colony forming unit (CFU) assays. These assays are hamper ed by interlaboratory variability and are not uniformly predictive. CD 34 quantification by flow cytometric technique has also been used to a ssess the quality of harvested marrow and PBSC. However, a lack of sta ndardization has hampered direct comparison of published reports. We s ought to characterize these early lineage-committed CD34(+) progenitor cells from non-ficolled harvested marrow with six progenitor cell (PC ) panels containing CD34 antibody plus two additional early lineage ma rkers, using multiparameter flow cytometry. The specific gating techni que including simultaneous CD34-PE vs. side scatter and forward vs. si de scatter, was verified using morphologic analyses of sorted CD34(+) cells. An ungated file was initially acquired to assess total CD34(+) content. A second file using a CD34 threshold was then acquired to res olve lineage-committed subsets. The % CD34(+) cells as well as cells/m u l of bone marrow was calculated using cell counts at the time of mar row harvest. Bone marrow (mean total cell dose = 3.8 x 10(8)/kg), obta ined from 42 normal donors for allogeneic transplantation was first an alyzed. CD34(+) cells comprised a mean 1.3% of non-ficolled marrow, wi th 328 CD34(+) cells/mu l, and mean CD34(+) cells collected was 4.8 x 10(8)/kg. While no significant differences in total cells harvested no r proportion of CD34(+) cells was found, a significant decrease in CD3 4 cells/mu l (= 233, P = .0012) was found in cancer patients. The perc entage of CD19(+) and CD38(+) progenitor cells was significantly incre ased, while CD5(+) and CD71(+) cells were decreased. The proportions o f all other early lineage-committed CD34 subsets were not different. M easurement of lineage-committed CD34 progenitor cells is a useful tech nique to characterize harvested marrow and PBSC, and may be applied to predict time and quality of engraftment post ablative conditioning re gimens. (C) 1996 Wiley-Liss, Inc.