Basophil and mast cell progenitor populations in Irf8^−/− mice. Flow cytometric analysis of basophil/mast cell progenitor populations in WT and Irf8^−/− mice. Representative flow cytometry data are shown. Numbers in the parentheses indicate the percentages relative to total cell counts. Values in the bar graphs are means ± standard deviations from 5 to 7 mice of each genotype. The reduced percentages of Lin⁻ cKit⁺ FcγRII/III⁻ CD34⁻ cells (megakaryocyte-erythroid progenitors) and Lin⁻ CD150⁺ Flt3⁻ cells (megakaryocyte-erythroid progenitor-like population) in Irf8^−/− mice are consistent with previous reports.³⁷  **P < .01; ***P < .001 (Student t test). FSC, forward scatter; NS, not significant.