Flow cytometric analysis of CXCR4 along megakaryocytic (Mk), monocytic (Mo), granulocytic (G), and erythroid (E) HPC differentiation. Cells were collected for analysis at the indicated days of culture and double-labeled with PE-conjugated anti-CXCR4 MoAb along with the specific cell-lineage FITC-conjugated MoAbs (-CD61, -CD14, -CD15, -Glyc-A). Representative results from 1 of 3 independent experiments are shown.