Background: Regulated suppression of maternal Th1 immunity is necessary for normal pregnancy since inappropriate Th1 responses results in increased pregnancy loss and complications including intrauterine growth restriction (IUGR). We have shown that suppression of the p65 subunit of NF-κB in maternal T-cells underlies this change in T-cell responses. This study aimed to determine mechanism(s) that control p65 suppression.

Intrauterine Growth Restriction (IUGR) is a leading cause of perinatal death with no effective cure, affecting 5–10% pregnancies globally. Suppressed pro-inflammatory Th1/Th17 immunity is necessary for pregnancy success. However, in IUGR, the inflammatory response is enhanced and there is a limited understanding of the mechanisms that lead to this abnormality. Regulation of maternal T-cells during pregnancy is driven by Nuclear Factor Kappa B p65 (NF-κB p65), and we have previously shown that p65 degradation in maternal T-cells is induced by Fas activation. Placental exosomes expressing Fas ligand (FasL) have an immunomodulatory function during pregnancy. The aim of this study is to investigate the mechanism and source of NF-κB regulation required for successful pregnancy, and whether this is abrogated in IUGR. Using flow cytometry, we demonstrate that p65+ Th1/Th17 cells are reduced during normal pregnancy, but not during IUGR, and this phenotype is enforced when non-pregnant T-cells are cultured with normal maternal plasma. We also show that isolated exosomes from IUGR plasma have decreased FasL expression and are reduced in number compared to exosomes from normal pregnancies. In this study, we highlight a potential role for FasL+ exosomes to regulate NF-κB p65 in T-cells during pregnancy, and provide the first evidence that decreased exosome production may contribute to the dysregulation of p65 and inflammation underlying IUGR pathogenesis.

Since preeclampsia was first described by Hippocrates in 400 BC, the theory of its causation has shifted from toxins to a current theory that incorporates both vascular and immunological causation. Poor placentation whether it is genetically predisposed or due to low expression of defective HLA-G on fetal trophoblasts is believed to be the initial insult. Oxidative stress from placental ischemia/hypoxia leads to an overload of trophoblast debris by stimulating apoptosis or necrosis. Partial failure of the maternal immune system to tolerate the paternal alloantigens activates maternal immune cells to secrete cytokines whose pleiotropic functions lead to dysfunction of the maternal vascular and placental endothelium, blood coagulation, and fibrinolytic system. This chapter describes some of the key methodologies (flow cytometry, ELISAs, and multiplex immunoassays) for the identification and quantification of inflammation and immune system markers in the study of preeclampsia pathogenesis, as well as diagnostic and therapeutic development. The methodologies may be utilized for a variety of tissue sources in the study of preeclampsia: maternal peripheral blood, umbilical cord blood, intervillous blood, decidua, chorionic villous, amnion and chorion membranes, and cell culture supernatant.