Forodesine induced loss of ΔΨm and ROS production in CLL cells. Cells from patients with CLL were preincubated for 1 hour with the ROS scavengers GSH, NAC, or Tiron and treated with forodesine (2 μM) and dGuo (10 and 20 μM) for 16 hours. Loss of ΔΨ_m (DIOC₆ staining) and ROS production (dihydroethidine staining) were analyzed by flow cytometry. Data of 3 representative cases are shown as the mean value ± SD of triplicated points.