MDSCs in pregnancy and pregnancy-related complications: an update


 Maternal-fetal immune tolerance is a process that involves complex interactions of the immune system, and myeloid-derived suppressor cells (MDSCs) have emerged as one of the novel immuno-modulator in the maintenance of maternal-fetal immune tolerance. MDSCs are myeloid progenitor cells with immunosuppressive activities on both innate and adaptive cells through various mechanisms. Emerging evidence demonstrates the accumulation of MDSCs during healthy pregnancy to establish maternal-fetal immune tolerance, placentation, and fetal-growth process. In contrast, the absence or decreased MDSCs in pregnancy complications like preeclampsia, preterm birth, stillbirth, and recurrent spontaneous abortion has been reported. Here, we have summarized the origin, mechanisms, and functions of MDSCs during pregnancy along with the recent advancements in this dynamic field. We also shed light on the immunomodulatory activity of MDSCs, which can be a foundation for potential therapeutic manipulation in immunological pregnancy complications.