IRF5 serves as a master regulator of macrophage polarization.13 It senses danger signals and induces inflammatory gene expression, giving rise to M1 macrophages.10 The silencing or a deficiency of Irf5 hampers M1 macrophage polarization,1 and in our study, we also confirmed that the myeloid-specific ablation of Irf5 reduces M1 macrophage polarization in the intestines of mice affected by NEC. The gene discussed is IRF5; the disease is necrotizing enterocolitis.