Sex, age, and the macrophage

Macrophages Peritoneal macrophages are known to contribute to pathology of peritonitis, endometriosis, and cancer, but the effects of age and sex on the biology of these cells are not well understood. Bain et al. show that replenishment of peritoneal macrophages from the bone marrow is much higher in male mice than in female mice. This disparity results in marked sexual dimorphisms in the phenotypic identity of peritoneal macrophages, including differential expression of a receptor involved in response to bacterial infection. These findings provide insight into the effects of sex and age on peritoneal inflammation and infection. Sci. Immunol. 5 , eabc4466 (2020).