Multimodal profiling of term human decidua reveals immune adaptations with maternal obesity - Villous

The leukocyte diversity of the early maternal-fetal interface has been recently described, however, the immunological landscape of the decidua at term is still pending. We, therefore, profiled the CD45+ compartment within human term decidua collected via cesarean section. Relative to the first trimester, our analyses revealed a shift from NK cells and macrophages to T-cells and enhanced activation of all immune cells. Decidual T-cells in the decidua were phenotypically distinct from those in circulation and demonstrated significant clonotype sharing. Using pseudo-temporal analyses of macrophages, we report previously unappreciated diversity of bonafide tissue resident decidual macrophages. The frequency of this population positively correlated with pregravid maternal body mass index but responded poorly to bacteria ligands. Collectively, these findings provide evidence of skewing of decidual myeloid cells towards immunoregulation representing a possible mechanism to safeguard the fetus against maternal inflammation. This immune cell atlas of term decidua is an asset for future studies investigating pathological conditions that compromise reproductive success.