A subset of NKG2C+ dNK1 may provide benefits in secondary pregnancy through immunological training,33 while dNK2 and dNK3 cells may engage with other cell types in the decidua through the production of other factors such as XCL-1, which can attract both DCs and trophoblast.316 As inflammation and infections are associated with abnormal placental vascular development317,318 and dNK cells play a significant role in placental vascularization, one of the remaining important research questions is how placental and systemic infection can influence the vascular remodeling function of dNK cells. Here, XCL1 is linked to infection.