Role of Innate Immunity in Preeclampsia: A Systematic Review

Abstract

Innate immune system dysfunction has been known to be a key player in preeclampsia (PE). Activation of the maternal innate immunity may be triggered by invading microorganisms or endogenous ligands, which are detected by different pattern recognition receptors (PRRs). Although some studies have linked PRR activation to PE, it is still unclear if dysregulated PRR expression is associated with the development of this complication. Therefore, we conducted a systematic review of the literature, searching articles that evaluated associations of PRRs with PE. Twenty-six studies met the inclusion criteria: 20 of them analyzed PRR expressions and 6 studies investigated the association between PRR polymorphisms and PE. Among the PRRs, only few studies analyzed retinoic acid-inducible gene I-like helicase (RLH) and/or toll-like receptor (TLR)-1, 5, 6, 7, 8, and 9 expressions in immune cells or placentas from women with PE and controls; thus, it is inconclusive if these PRRs are involved in PE. Results from the 10 studies that analyzed TLR-2 expressions in women with PE and controls are also contradictory. The majority of the studies that investigated TLR-3 and -4 expressions indicate that these PRRs are increased in placenta or immune cells from women with PE compared to pregnant control woman. To date, polymorphisms in TLR-2, - 3, and - 4 and nucleotide-binding oligomerization domain-like receptor 2 genes do not seem to be associated with PE development. No study has evaluated the association between polymorphisms in genes codifying other TLRs or RLHs genes. In conclusion, available data in literature support a role for TLR-3 and TLR-4 in the pathogenesis of PE.

Impact of pregravid obesity on maternal and fetal immunity: Fertile grounds for reprogramming

“…[128][129][130] For instance, studies have reported decreased IL-35 and IL-9 levels and concurrent drop in CD11c+ myleloid cells and regulatory T cell populations over the course of gestation. 128 Local changes in frequencies, phenotype, and functions of immune cells in the decidua and villi have been attributed in the pathogenesis of several obstetric complications such as preterm labor, 131 PE, [132][133][134] and chorioamnionitis. 135 Indeed, first trimester placentas from women with obesity show reduced uterine NK cell numbers, which normally comprise ∼70% of the leukocyte population in early human decidua and play a central role in uterine artery remodeling and altered expression of genes in pathways associated with matrix remodeling and growth factor signaling 136 (Fig.…”

Toll‐like receptors signaling network in pre‐eclampsia: An updated review

“…oxidized low-density lipoprotein and hyaluronic acid (Bouças et al, 2017;Yeh et al, 2013). It is assumed that as the result of the presence of bacterial or viral products like Bacterial LPS or viral dsRNA, trophoblast cells through the upregulation of TLRs and subsequent generation of differential chemokine profiles and excessive recruitment of neutrophils, monocytes and NK cells into the maternal-fetal interface trigger abnormal immune responses and further inflammation in PE patients .…”

Impact of Advanced Maternal Age on Physiologic Adaptations to Pregnancy in Vervet Monkeys

“…Growing evidence indicates a role for adaptive immune cell activation in the context of preeclampsia 32 . We therefore assessed circulating components of the adaptive immune system including monocytes, basophils, neutrophils and eosinophils.…”