Identification of PEM population in unexpanded cord blood. Cells collected from day 14 cord blood CD34⁺ Y* CGS expansion cultures (A) and fresh CB MNCs (B) were analyzed by immunofluorescent staining and flow cytometry for CD235a⁺/CD41a⁺ PEM and coexpression of the primitive hematopoietic markers CD34 and CD123. Gates were set based on isotype staining controls (see examples shown under the 2-color plots). The percent of cells in each quadrant or gate are indicated.