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

BACKGROUND: The use of autologous peripheral blood progenitor/stem cells as part of dose-intensified treatment protocols for patients with acute myeloid leukemia (AML) is under current clinical investigation. METHODS: We analyzed the frequency of CD 34 + 38 - and CD 34 + DR - subpopulations, clonogenic cells and long-term culture-derived clonogenic cells (LTC-DC) in peripheral blood (PB) samples from patients with AML after chemotherapy and G-CSF given for mobilization in comparison to a control population of patients with non-hematological malignancies. RESULTS: We observed a lower number of CD 34 + cells (31.2 ± 14.8 vs. 114 ± 36 /μl) and a reduction to less than 15 % for clonogenic progenitors (CFU) and LTC-DC in peripheral blood mononuclear cells from AML patients after consolidation therapy. In contrast, the quality of these CD 34 + cells was not significantly impaired after consolidation therapydetermined by a moderately reduced frequencyof CFU/CD34 + cells (5.0 ± 1.5 % vs. 10.0 ± 2.8 %), a nearly identical frequency of LTC-DC/CD34 + cells (0.5 ± 0.1 % vs. 0.6 ± 0.2 %), and a higher percentage of CD 34 + 38 - cells/CD34 + cells (8.4 ± 1.8 % vs. 3.8 ± 1.1 %) in comparison to the control population. CONCLUSION: Our data confirm that it is possible to mobilize CD 34 + cells into the peripheral blood of AML patients using chemotherapy and G-CSF. Nevertheless, the low absolute number of CFU and LTC-DC after high-dose ara-C treatment for AML has to be taken into consideration for the design of treatment protocols using autologous progenitor/stem cell transplantation.