Flow cytometric histograms of an MRP1(+) 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 are negative for MDR1. (C and D) Leukemic blasts stained with the monoclonal antibodies LRP and MRPm6 (red) compared to the control. The blasts are LRP(+) and 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 efflux of Rh123 that is not inhibited by CsA (E). No Di(OC)2 efflux is shown (F). (G and H). Rh123 efflux after incubation of leukemic blasts for 18 hours in the absence (G) or presence of BSO (H). Cellular fluorescence after efflux (red) compared with baseline (black). Rh123 efflux is detected (G) that is inhibited by BSO incubation.
