Flow cytometric detection of MDR1/P-gp expression.

Flow cytometric histograms of MDR1 expression in the VBL cell line by single staining with the MRK16 mAb (A), analyzed according to the Kolmogorov-Smirnov test (B). Dot plots of a representative ALL sample in which leukemic cells were identified by double staining with IgG2a/CD19 (C) and MRK16/CD19 (D). Histogram (E) made according to the method of Kolmogorov-Smirnov36 to compare fluorescence of the IgG2a isotypic control (black) with the MRK16 (white) mAb.