IL10 and rheumatoid arthritis: We previously showed that RA patients had defective monocyte polarization toward an M2-like macrophage phenotype (CD11bLo–CD71Lo; CD206Lo; CD163Lo with decreased interleukin 10 [IL-10] secretion) in favor of an M1-like phenotype (inducible nitric oxide synthase+, interferon regulatory factor 5+, and increased levels of pro-inflammatory cytokines such as IL-1β–IL-6–macrophage inflammatory protein 1α) (6).