Four examples of fresh leukemic samples. The first example is a sample with high Pgp expression (a) and with high MRP expression (b) (measured by flow cytometry). There is an important modulatory effect of CsA on calcein-AM uptake (A) and an important effect of probenecid on calcein efflux (B). The second example is a sample with no Pgp expression (c) and with a weak MRP expression (d). There is no modulatory effect of CsA on calcein-AM uptake (C) and a little modulatory effect of probenecid on calcein efflux (D). The third and fourth examples are samples with high Pgp expression (e and g) and no MRP expression (f and h). In these two examples, there is an important modulatory effect of CsA on calcein-AM uptake (E and G) and no modulatory effect of probenecid on calcein efflux (F and H). *Controls: autofluorescence of the cells that were not exposed to calcein-AM. †We used the ratio of MDR MoAbs (UIC2 or MRPm6) fluorescence divided by control MoAbs (mouse isotype-matched control MoAbs, IgG2A for UIC2 and IgG1 for MRPm6) fluorescence. ††All the data were calculated as the ratio of drug fluorescence with modulator divided by drug fluorescence without modulator after subtraction of the fluorescence of the control.