Functional characterization of PB CD34⁺progenitor cells from patients with CLL. (A-C) Bar plots showing the absolute number of colony-forming units (CFU) generated in methylcellulose assays by PB CD34⁺ of (A) healthy controls (n = 17) and of patients with CLL (n = 55) (unpaired Student t test; P < .05). Comparison between healthy controls and Binet groups (B) or treatment-naive patients with CLL vs treated patients (C) (ordinary 1-way ANOVA followed by unpaired Student t tests). Differentiated colonies were counted and scored based on morphology 14 days postculture in humid environment at 37°C. Colonies were analyzed using STEMVision (STEMCELL Technologies). (D) Representative pictures of CFUs generated by healthy or CLL-derived hematopoietic progenitors. BFU-E, burst forming unit–erythroid; CFU-GEMM, colony-forming unit–granulocyte, erythrocyte, macrophage, megakaryocyte; CFU-GM, colony-forming unit–granulocyte, macrophage. (E-F) Dot-plots showing the composition of CFUs generated by healthy controls and patients with CLL (E) or by naive patients with CLL or treated patients with CLL (F) (1-way ANOVA followed by unpaired Student t test). (G) Histograms showing myeloid (left) or erythroid (right) CFU frequencies in CLL samples clustered based on chromosomal abnormalities. P values from unpaired Student t tests or 1-way ANOVA are denoted with asterisks according to the following: ***P < .001, *P < .05.