Quantitation of mafosfamide-resistant pre-colony-forming units in allogeneic bone marrow transplantation: relationship with rate of engraftment and evidence for long-lasting reduction in stem cell numbers

Abstract

Current assays of human committed-stem cells are of limited value in predicting the rate of engraftment or in assessing the integrity of the stem cell pool after allogeneic bone marrow (BM) transplantation (BMT). We have used a limiting dilution assay of mafosfamide-resistant progenitors (pre-colony-forming units [CFU]), which are ancestral to committed progenitors such as CFU-granulocyte-macrophage (GM) to analyze the kinetics of myeloid engraftment after BMT and to assess the size of the stem cell pool at intervals up to 66 months thereafter. In 24 patients transplanted for chronic myeloid leukemia in chronic phase (eight with matched unrelated donors and 16 with sibling donors), the rate of neutrophil engraftment correlated strongly with the number of pre-CFU transfused per kilogram recipient body weight (r = .7, P < .005) but not with CFU-GM per kilogram or nucleated cells per kilogram. In 25 patients studied 6 to 66 months after allogeneic BMT, the mean number of pre-CFU in the marrow was 3.1/10(5) mononuclear cells (MNC) (median, 3.47; range, 0.4 to 23.3), compared with 24.7/10(5) MNC (median, 27.3; range, 4.2 to 180) in 25 normal subjects. CFU-GM were also reduced in these patients, but with considerable overlap into the normal range (mean +/- SD: 54 +/- 45.6 per 10(5) MNC; normal, 129 +/- 61.6). Low pre-CFU but not low CFU-GM levels were associated with reduced peripheral blood white blood cell counts in post-BMT patients. Pre-CFU and CFU-GM levels were not related to the interval posttransplant and remained low for up to 66 months. We conclude that the pre-CFU assay measures a population of stem/progenitor cells that are important in the kinetics of engraftment after allogeneic BMT. Our data suggest that pre-CFU levels may remain low for some years after BMT in humans.

HIGH‐DOSE THERAPY WITH PERIPHERAL BLOOD STEM CELL TRANSPLANTATION RESULTS IN A SIGNIFICANT REDUCTION OF THE HaEMOPOIETIC PROGENITOR CELL COMPARTMENT

“…We have previously shown that during G-CSF-enhanced recovery PB is enriched with the more immature CD34 / Thy1 progenitor cell subset (Haas et al, 1995a), but following PBSC-supported high-dose therapy the proportion of this subpopulation and of CD34 /DR ÿ cells is significantly reduced in BM, when compared with pre-mobilizationvalues. This finding is similar to the results of Kirkland et al (1996) who showed a reduced number of mafosfamide-resistant primitive progenitor cells after BMT. In contrast, the number of CD34 /CD33 cells post-transplantation was increased.…”

“…We report on a reduction in the proportion of CD34 cells and colony-forming cells in BM and PB in patients after PBSCsupported high-dose therapy. A similar finding was made in patients following autologous or allogeneic bone marrow tranplantation (Barrett & Adams, 1981;Li et al, 1985;Ma et al, 1987;Vellenga et al, 1987;Messner et al, 1987;Mauch & Hellman, 1989;Domenech et al, 1995;Kirkland et al, 1996). The patients in this study were evaluated before PBSC mobilization and after a minimum observation period of 6 months post-transplantation.…”

“…Previous studies have demonstrated an impairment of the clonogenic ability of bone marrow derived progenitor cells following BMT (Barrett & Adams, 1981;Li et al, 1985;Ma et al, 1987;Vellenga et al, 1987;Messner et al, 1987;Mauch & Hellman, 1989;Domenech et al, 1995;Kirkland et al, 1996). Considering the advantages of blood stem cell transplantation over BMT, with respect to short-term recovery, we were interested in the effect of high-dose therapy with PBSC transplantation on bone marrow function posttransplantation.…”

Haemopoietic defect and decreased expansion potential of bone marrow autografts from patients with acute myeloid leukaemia in first remission

“…In addition to its direct toxic effect, chemotherapy may induce premature ageing of the stem cell population by the serial cycles of repopulation it induces in vivo. This hypothesis is supported by the long-lasting haemopoietic defect observed after repopulation following ABMT (Domenech et al, 1995), allogeneic BMT (Kirkland et al, 1996) and peripheral stem cell transplantation (Voso et al, 1996). A third possibility is that acute myeloid leukaemia is responsible for a long-lasting haemopoietic inhibition (Van Bekkum et al, 1981).…”

Combination of stem cell factor and granulocyte colony‐stimulating factor mobilizes the highest number of primitive haemopoietic progenitors as shown by pre‐colony‐forming unit (pre‐CFU) assay

“…The synergy between SCF and G-CSF in mobilization could be related to the lower expression of c-kit (reviewed in Roberts et al, 1999). By comparison, the lack of significant synergism with the combination of IL-3 and GM-CSF is understandable because both cytokines share signalling through a common receptor b-chain (Le Âvesque et al, 1995).…”