NE and MPO protein expression is decreased in SCN granulocytic precursors. Confocal microscopy of 2 different healthy donors (normal) and 3 ELA2-mutant SCN samples stained with NE and myeloperoxidase (MPO; a primary granule constituent). Isotype controls for NE and MPO are shown. Data are representative of 6 normal and 6 ELA2 mutation-positive SCN bone marrow samples.