PML inhibits the CSF3 response of ELANE-I60F HPCs. (A) CFU-G assays on ELANE-I60F bone marrow cells showing a very limited CSF3 response with increasing dosages of CSF3, where HAX1-W44X and normal bone marrow cells show a CSF3-induced increase in colony formation. (B) CFU-G assays on iPSC-derived HPCs showing a similar hyporesponsiveness in ELANE-I60F cells, which is restored upon correction of the mutation and partly restored by the removal of PML (data are pooled from 3 independent experiments performed in triplicate). Dashed line indicates a nonlinear fitted curve. (C) Representative FACS histogram depicting CD11b expression (left) and subsequent quantifications of the myeloid cells present in CSF3-containing liquid culture (right; n = 3) showing an elevated ratio of immature vs mature myeloid cells in ELANE-I60F cells relative to controls, which was partly reverted to normal after PML knockout (ELANE PML^−/−, ELANE-I60F PML^−/−). *P < .05, **P < .01. (D) Representative May Grünwald-Giemsa–stained images of parental, PML-deficient, and corrected ELANE-I60F cells.