Content of long‐term culture‐initiating cells, clonogenic progenitors and CD34⁺cells in apheresis harvests of normal donors for allogeneic transplantation, and in patients with acute myeloid leukaemia or multiple myeloma

Abstract

Using a limiting dilution assay the frequency of long‐term culture‐initiating cells (LTC‐IC) in the apheresis products following mobilization by granulocyte‐colony stimulating factor (G‐CSF) with or without chemotherapy from 14 normal donors (ND) for allogeneic bone marrow transplantation, 16 patients with multiple myeloma (MM) and 15 patients with acute myeloid leukaemia (AML), where the aphereses were intended for autologous transplantation, were compared. The estimated median incidences of LTC‐IC in the first apheresis products from ND, MM and AML were 1/3289, 1/1775 and 1/13 075 mononuclear cells (MNC) respectively. The patients with AML had a significantly lower incidence compared with the other two groups (P < 0.0001). There was a positive correlation between the incidence of LTC‐IC and the number of CD34+ cells, the number of GM‐CFC, and the number of BFU‐E. The positive association with GM‐CFC or BFU‐E was weaker. In these experiments the percentage of CD34+ cells was the best predictor for the frequency of LTC‐IC in the peripheral blood progenitor cells (PBPC). In eight cases of MM the LTC‐IC assay was performed for both the first and second harvest. All cases had a lower LTC‐IC frequency in the second harvest compared with the first, an average of 23% (13–42%, 95% confidence interval) and this reduction was statistically significant (P < 0.001); CD34+ cells were also lower (P < 0.001).

Better preservation of early hematopoietic progenitor cells when human peripheral blood progenitor cells are cryopreserved with 5 percent dimethylsulfoxide instead of 10 percent dimethylsulfoxide

“…We observed a significant correlation between the percentage and/or number of viable CD34+ cells and LTC‐CFC number in frozen PBPC concentrates when using both 5 percent DMSO and 10 percent DMSO, and this is similar to previous results for fresh PBPC concentrates 21 . This observation suggests that the percentage and/or number of viable CD34+ cells is a marker for LTC‐IC numbers in PBPC autografts when using both 5 percent DMSO and 10 percent DMSO.…”

Human Haematopoiesis in Steady State and Following Intense Perturbations

“…It may also explain the very low levels of anti-HIV1 gene expression in the peripheral blood leukocytes of patients treated with genetically modified marrow (Kohn et al, 1999). Our mathematical analysis as well as recent clinical evidence (Kasper et al, 1999) imply that a potentially high number of stem cells can be obtained by PBSC harvest. This suggests that efficient haematopoietic stem cell gene transfer is feasible if enhanced by combinations of growth factors and transfection media that selectively activate quiescent stem cells without causing differentiation.…”

CD34-Subpopulations and Clonogenic Progenitors in Mobilized Peripheral Blood Cells from Patients with Acute Myeloid Leukemia

“…Therefore, we used several functional assays to analyze the quality of PBSC from AML patients after high-dose ara-C containing consolidation therapy, as well as from AML patients after induction therapy. Other groups have reported data on the total yield of CD 34 + subpopulations including LTC-DC and CFU in leukapheresis preparations [12,25]. We used peripheral blood samples for those patients not leukapheresed and calculated the frequencies of all subpopulations in relation to the MNC fraction as well as to the CD 34 + cell population and investigated all patients successively entering the current treatment protocol for AML at our institute in order to avoid any selection bias.…”