Flow cytometric analysis of CD200 expression on 65 primary AML samples. (A) Proportion of CD200⁺ cells in the CD3⁻CD19⁻ MNC and CD45⁺ (dim/high) populations. (B) CD200 vs CD45 expression profiles of 9 AML cases. Red dots represent CD3⁻CD19⁻ MNCs stained with anti-human CD200 mAb (clone 1B9). Blue dots represent CD3⁻CD19⁻ MNCs not stained with anti-human CD200 mAb (fluorescence minus 1 control). CD45^dimCD200⁺ blast populations are indicated by dashed circles. (C) Proportion of CD200⁺ cells in CD34 and CD38 subpopulations. (D) Correlation between CD34 and CD200 expression on CD45^dim blasts (diagonal line represents a correlation of 1) (left panel) and comparison of CD34 and CD200 expression on CD45^dim blasts from samples with ≤20% CD34 expression on blasts (right panel). ****P < .0001.