Immune cell composition at the feto-maternal interface in health and disease

Abstract

Abstract Objectives: We hypothesize that innate and adaptive leukocyte infiltration, function and localization within the placenta is altered in health and disease and that immune cell interactions play a crucial role in maintaining immune tolerance at the fetal-maternal interface. Methods: To evaluate the complexity and differences of the immune landscape in decidua basalis we examine tissue samples from healthy women and women who developed gestational diabetes (GDM). We use flow cytometry (18-plex), fluorescent multiplex immunohistochemistry and gene expression analysis. Results: Preliminary data suggest abundant innate immune cell infiltration (macrophages and neutrophils) as well as accumulation of T-cell and NK cell subsets at the fetal-maternal interface. In gestational diabetes mellitus pregnancies, we were able to observe lower T cell infiltration when compared to healthy, which was not seen in obese pregnant women. However, in both groups (obese and GDM) there was a trend for lower T regulatory cell infiltration. For monocyte and macrophage populations a trend towards lower immune cell infiltration was observed in both obese and GDM pregnancies when compared to healthy. 70–80% of macrophages show M2 polarization, which suggest that they have an important role in anti-inflammatory processes during pregnancies. We could observe also abundant neutrophil infiltration (up to 20% of all leukocytes), although there was no difference between heathy and diseased pregnancies. Conclusion: Our study comprehends a detailed picture of the immune landscape at the fetal-maternal interface in normal and GMD pregnancies, which will aid our understanding of possible dysfunctional immune mechanisms.