Flow cytometric histograms of a typical MDR1(+)/efflux(+) AML case. (A) Dot-plot showing laser light characteristics of leukemic blasts (forward scatter, x-axis; side scatter, y-axis). (B) Leukemic blasts stained with the MDR1-specific antibodies, MRK16 (red) and MM4.17 (green) compared with the control (black). The leukemic blasts stain positively with both antibodies. (C and D) Leukemic blasts stained with the monoclonal antibodies LRP and MRPm6 (red) compared with the control (black). The blasts are positive for LRP and negative for MRP1. (E and F) Flow cytometric histograms showing functional efflux of Rh123 and Di(OC)2 by leukemic blasts. Increasing cellular fluorescence (x-axis) plotted against cell number (y-axis). Functional efflux in the absence of the MDR1 inhibitor, CsA (green), is compared with efflux in the presence of CsA (red) and with the baseline (black). There is significant efflux of both Di(OC)2 and Rh123, which is blocked by CsA.
