IL-7Rα signaling stimulates the B-lymphoid fate and represses AP-1 transcription factors. (A) Expression of BACH2, EBF1, PAX5, CD74, and CXCR4 plotted across the pseudotime of the early BCP subset as shown for controls and patients. (B) Dot plots showing expression of the EBF1 and PAX5 target genes CD79A, CD79B, VPREB1, and IGLL1 in early BCP clusters in controls vs patients. (C) Flow cytometric quantification of PAX5, CD79A, and CD19 expression in indicated BCP populations in the BM of controls and patients. (D) Heatmap showing expression of myeloid and lymphoid genes in early BCP clusters with unsupervised clustering. (E-H) Flow cytometric quantification of EBF1 (E), PAX5 (F), cytoplasmic CD79A (G), and CD19 (H) expression in individual BCP populations in IL-7–stimulated vs unstimulated BM cultures at day 14. Representative histograms are shown in supplemental Figure 6. Bar graphs show the median with interquartile range (E,G-H) or mean with standard error of the mean (F). Statistical analysis was performed with multiple Mann-Whitney tests (E,G-H) or unpaired t tests (F) and corrected for multiple comparisons with the Holm-Šídák method. Data collected from 3 experiments with 3 different BM donors. All replicates are shown (n = 3 BM samples, each with 3 or 6 replicates). (I) Violin plots showing expression of JUN and FOS family members across all clusters in patients vs controls. P values are denoted as follows: ∗∗P < .01; ∗∗∗P < .001; ∗∗∗∗P < .0001.