In homeostasis conditions, two subpopulations of neutrophils have been disclosed, although their precise functions are still unknown: cluster of differentiation (CD) 177 + neutrophils appear to be involved in anti-neutrophil cytoplasmic antibody-associated vasculitis, [31] while neutrophils expressing Olfactomedin-4, a candidate neutrophil subset marker, are associated with an increased risk of death in patients with septic shock, [32] although no substantial differences have been observed between neutrophils expressing Olfactomedin-4 and those that do not. Here, OLFM4 is linked to septic shock.