In vitro proliferation and expansion of human hematopoietic progenitor cells from normal subjects and patients with hematologic neoplasias

Abstract

We have assessed the proliferation (capacity to divide and produce more cells) and expansion (capacity to generate more progenitor cells) potentials of CD34(+)-enriched cell populations from normal bone marrow (nBM; n = 2), umbilical cord blood *UCB; n = 8) and marrow from patients with AML (n = 7), CML (n = 3) and MDS (n = 4). CD34(+) cells were enriched by using the StemSep system (StemCell Technologies Inc; STI). In most cases, CD34(+) cells comprised 40%–70% of the post-column cell population; only in AML such a proportion varied from 0%–50%. Cells were cultured in MyeloCult medium (STI) supplemented with SCF, IL-6, GM-CSF and G-CSF. In nBM cultures, a 169-fold increase in total cell number was observed by day 20 of culture; however, there was no progenitor cell expansion, determined on day 10. UCB cultures showed a 203-fold increase in total cell number, also by day 20, and a 7.5-fold increase in progenitor cell number. In AML cultures, total cell numbers were increased only 2.14-fold (day 15) and no progenitors were detected. CML cultures showed a 60-fold increase in total cell number (day 15), but no progenitor expansion was observed. In samples from MDS patients (RA and REAB-t), a 6–12-fold increase was observed in total cell number and no progenitor expansion was detected. In contrast, in one patient with CMML, a 5,000-fold increase in total cell number (day 20) and 18.7-fold increase in progenitor cell number was observed. Our results confirm a higher proliferation/expansion potential of UCB CD34(+) cells, as compared to their nBM counterparts, and show clear abnormalities in the proliferation/expansion capacities of CD34(+) cells from patients with hematologic neoplasias of myeloid origin.