Correlation between fludarabine uptake and ex vivo sensitivity to fludarabine.

CLL lymphocytes were incubated for 48 hours either in the absence or in the presence of fludarabine at different concentrations (3 μM [A] and 7.5 μM [B]). Cell viability was determined by an MTT assay. Data are shown as the mean value of triplicate cultures. Correlation coefficient and P values are given in “Results.”