CK2 inhibition selectively targets the viability of CLL cells without significantly affecting normal lymphocytes. (A-B) PBMCs from CLL patients (n = 31) were cultured with 25μM DRB and viability of T cells and CLL cells was assessed after 48 hours. (A) Viability index, calculated as the ratio between viable cells in medium with and without CK2 inhibitor, was compared between T and CLL cells within each patient sample. (B) CD3/CD19 phenotype of viable (annexin V/7-AAD double-negative) PBMCs from a representative CLL patient. CD3⁺CD19⁻, T cells; CD3⁻CD19⁺ CLL cells. Numbers represent the percentage of cells in each quadrant. (C-D) PBMCs from CLL patients (n = 7) and age-matched healthy controls (n = 7) were cultured for 48 hours with or without 25μM TBB. (C) Viability of normal B and T cells was determined by annexin V/7-AAD staining. Results from one representative healthy donor are shown. Numbers represent the percentage of cells in each quadrant. (D) Viability index was compared between normal T and B cells from healthy donors and leukemic B cells from CLL patients.