T-bet has lineage-separating properties in CLL. (A) Expression of T-bet–dependent genes in untransformed B-cell subsets (n = 5-7) and CLL cells (n = 10). (B-C) Activity scores of T-bet were calculated based on (B) induced and (C) repressed genes individually for untransformed B-cell subsets and CLL cells. P values were obtained by 1-way ANOVA and controlling the FDR using the BH method. (D) Correlation between TBX21 gene expression and T-bet activity. P values were obtained using Pearson correlation testing. (E-F) Analysis of B-cell subsets in the human tonsil atlas with a representation of T-bet expression in different clusters. (F) T-bet activity scores in human tonsillar B cells calculated based on induced genes by T-bet in the CLL cells. P values were obtained using the Mann-Whitney test. ∗∗P < .01; ∗∗∗∗P < .0001.