Effect of COX inhibitors on the viability of B-CLL lymphocytes. Cells were incubated for 48 hours with 5 mmol/L aspirin, 10 μmol/L ketorolac, 100 μmol/L NS-398, or 20 μmol/L indomethacin. Cell viability was determined by the MTT assay as described in the Materials and Methods and is expressed as a percentage of the viability of control cells at the beginning of the culture. Data are shown as the mean value ± SD of 3 independent experiments. Statistical significance of differences between control cells and cells treated with COX inhibitors was assayed by ANOVA, Fisher’s PLSD. **P < .0001.