The role of macrophages in reproductive-related diseases.

The study of reproductive immunology includes the role of immunity in reproductive physiology and reproductive-related diseases. Reproductive-related diseases cause low pregnancy rate mainly through ovulation disorders, low-quality sperm production, embryo implantation failure and pregnancy maintenance disorders. Numerous cell types including infiltrating immune cells perform specific functions in the reproductive system. Physiologically macrophages are enriched in the decidua and testes, and macrophages are involved in endometrial receptivity, embryo implantation and spermatogenesis. Pathologically macrophages are associated with alterations of decidual microenvironment in recurrent implantation failure (RIF) and unexplained recurrent miscarriage (uRM), local inflammation in polycystic ovary syndrome (PCOS) and clearance of endometriotic lesions in endometriosis. Although researchers have recently attempted to uncover the pathogenesis and provide effective treatments for the reproductive-related diseases, the specific mechanisms and effective therapies need to be further explored. Here we summarized the latest mechanisms by which macrophages participate in the progression of the reproductive-related diseases, and the promising immune-based treatments. In addition, we discussed decidual macrophage classification and the importance of immune networks in reproduction-related diseases.