In a model of peritonitis, classically activated monocyte-derived M1 macrophages characterized by the expression of inducible Nitric oxide synthase (iNOS) and pro-inflammatory cytokines and chemokines in response to IFN-gamma and TLR ligands, undergo reprogramming, leading first to the acquisition of an M2-like phenotype characterized by high efferocytosis and then to the concomitant expression of pro-inflammatory cytokines and IL-10 [30]. The gene discussed is NOS2; the disease is peritonitis.