ELA2 mRNA expression in myeloid cells and NE protein levels in plasma are severely down-regulated in patients with CN. (A) ELA2 mRNA expression in BM cells at different stages of granulopoiesis. Different cell populations were isolated from BM smears from 3 healthy volunteers (blue line) and 4 patients with CN (red line). ELA2 mRNA expression was measured by qRT-PCR normalized to β-actin and is presented as arbitrary units (AUs); data represent means ± SDs of triplicates. (B) ELA2 mRNA expression in CD33⁺ cells from studied groups: 8 patients with CN harboring ELA2 mutations (CN, ELA2 Mut), 4 patients with CN with HAX1 mutations (CN, HAX1 Mut), 4 patients with CyN, 5 healthy volunteers without G-CSF treatment (ctrl), and 3 healthy volunteers treated with G-CSF (ctrl). ELA2 mRNA expression is normalized to β-actin (and is presented as AUs) l data represent means ± SDs measured in triplicates (*P < .05; **P < .01). (C) NE plasma levels were measured in different groups of patients and healthy volunteers indicated above, using NE-specific ELISA. Data represent means ± SDs and are derived from 2 independent experiments each measured in triplicate; **P < .01. (D-E) Analysis of the ELA2 mRNA stability in THP1 (D) and NB4 (E) myeloid cell lines after inhibition of mRNA transcription by actinomycin D in the absence (red, ctrl) or presence (blue, G-CSF) of G-CSF. The data represent the percentage of remaining ELA2 mRNA after actinomycin D treatment for the indicated time points, compared with initial ELA2 mRNA amounts. Data represent means ± SDs and are derived from 2 independent experiments each measured in triplicate.