Effect of DEX on circulating CLL cells. (A) CLL cells were purified and cultured for 48 hours with or without DEX (30 μM) in serum-free media (RPMI-1640 with transferrin and 0.02% albumax) in the presence or absence of the GR antagonist mifepristone (1 μM). After 48 hours, percentages of viable 7AAD⁻ cells that exclude 7AAD were determined by flow cytometry and are shown in the right upper corners of the dot-plots. Mifepristone prevented DEX-induced cell death. (B) Results for 52 different CLL patient samples are shown. Each line represents percentages of 7AAD⁺ cells after 48 hours in the presence or absence of DEX. (C) Circulating CLL cells from the indicated patients were cultured for 4 hours with or without DEX. Levels of Ser211 phosphorylated GR (P-GR) were measured by immunoblotting with β-actin as a loading control and quantified by densitometry. (D) Summary of forward scatter median measurements at 48 hours by flow cytometry indicating that DEX significantly decreased the size of circulating CLL cells. **P < .01.