Modulation of an immune regulatory program in CLL cells by BTKi therapy. (A) Heatmap of 22 immunomodulatory genes that were significantly modulated by BTKi therapy (absolute fold change >1.5, false discovery rate <0.1). Depicted is the log² fold change after 6 months of treatment with ibrutinib (n = 14) or acalabrutinib (n = 20) compared with baseline. (B) Expression of CD200 (n = 16) and (C) intracellular CTLA-4 (n = 12) were measured by flow cytometry in CLL cells before starting therapy (baseline, gray triangles) and after 6 months on a BTKi (acalabrutinib [purple circles] or ibrutinib [green diamonds]). Mean fluorescence intensity (MFI) of the entire CLL population is shown. Statistical significance by Wilcoxon matched-pair signed-rank test. ***P < .001; ****P < .0001.