NmU enhances primary erythroid progenitor expansion. Primary human CD34⁺ cells from cord blood were cultured under erythroid-inducing conditions in the absence and presence of NmU peptide. (A) At days 6, 8, and 10 in culture, cells were stained for CD71 and GlyA expression, detected by flow cytometry, and analyzed by FlowJo software Version 4.5.8. Maturation-specific erythroid gates were drawn in accordance with flow cytometry models of human erythroid development.²⁷  High expression of CD71 and moderate expression of GlyA are observed in the earliest erythroblasts (group I). As the cells mature, GlyA expression increases whereas CD71 expression declines (groups II-IV). Shown are the results from a representative flow cytometry experiment from 3 independent determinations. The plots to the right of flow cytometry experiments completed on days 8 and 10 compare the average percentage of cells in groups I through IV in the presence of EPO or EPO and NmU peptide. *P < .05. (B) CD34⁺ cells from cord blood cultured in the presence of IL-3, IL-6, and SCF; EPO without and with NmU was added on day 6 of culture. The cell number is presented as fold expansion relative to the CD34⁺ cell number on day 0. A representative fold expansion dot plot is shown from 3 independent experiments. The mean fold expansion at days 8 and 10 are shown as a bar graph. *P < .05.