Research Article

Lymphoid Progenitor Cells from Childhood Acute Lymphoblastic Leukemia Are Functionally Deficient and Express High Levels of the Transcriptional Repressor Gfi-1

Figure 3

Normal apoptosis rates but poor proliferative capabilities mark the early steps of lymphoid development in ALL. Mononuclear cells from control and ALL bone marrow (BM) were fractionated according to CD34 expression and analyzed by flow cytometry (a). The cell cycle status of primitive CD34+ cells and of CD34āˆ’ maturing cells (as indicated from the flow cytometry gates) were examined by 7-AAD staining (b). The CD34+ cell frequencies in G0/G1, S, and G2/M phases of the cell cycle were tabulated (c). Apoptosis rates in highly purified HSC, MPP, and CLP populations were assessed by TUNEL (d), while the proliferative disadvantage in the total fraction of progenitor cells in ALL BM was highlighted by means of BrdU incorporation in stromal cell-free conditions (e). HSC: hematopoietic stem cells; MPP: multipotent progenitor; CLP: common lymphoid progenitor.
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