The UPR is activated in SCN promyelocytes/granulocytes. (A) Representative scatter plots of bone marrow cells from a healthy donor (normal) and a patient with ELA2-mutation positive SCN (A28T) stained for CD15 and CD16; data are gated to exclude CD14⁺ monocytes and CD9⁺ eosinophils. The boxed region shows the sorted CD15⁺ CD16^lo CD14⁻ CD9⁻ cell population. (B) The percentage of spliced XBP-1 mRNA in the sorted cell population is shown. (C) Expression of BiP mRNA relative to NE mRNA in the sorted cell population is shown.