Decrease in Regulatory T-cells and Increase in T Helper 17 Cells in Women With Recurrent Spontaneous Abortion

Abstract

BackgroundAppearance of improper immune responses against the fetus and/or inadequate immunoregulatory mechanisms during pregnancy may lead to recurrent spontaneous abortion (RSA). TH17 cells play a significant role in inducing inflammation, autoimmune disease, and acute transplant rejection, while regulatory T (Treg) cells moderate the function of immune system in order to retain homeostasis.MethodsThis case-control study was designed to evaluate TH17 as well as Treg cells in 25 women with RSA and 25 age-matched healthy non-pregnant women. Flow cytometric assay was performed using monoclonal antibodies to detect CD4+CD25+ Treg cells (CD25dim and CD25bright). FoxP3 and RORγt expressions were compared using real-time PCR, and pro-inflammatory and anti-inflammatory cytokines were measured by ELISA kits. Independent-samples T test was employed for statistical analysis. ResultsThe ratio of CD4+CD25bright T cells was remarkably lower in women with RSA (P<0.05), and CD4+CD25dim T cells did not show any significant difference among the groups (P>0.05). RORγt was up-regulated, and FoxP3 was down-regulated significantly in case group (P<0.05). The significant increase of IL-6 and IL-17 as well as the decrease of TGF-β was indicated in RSA group (P<0.05). Also, IL-10 did not vary among the groups (P>0.05). ConclusionThese remarks prove that the decrease in regulatory factors such as CD4+CD25bright T-cells, TGF-β and FoxP3 expression may disrupt immune tolerance and homeostasis during pregnancy. Also, the environment rich in RORγt, IL-6, and IL-17 suggests the detrimental role of TH17 cells, which may lead to fetal rejection.

Immunogenetic Role of IL17A Polymorphism in the Pathogenesis of Recurrent Miscarriage

“…IL17 is more highly expressed in idiopathic RM patients than in nonpregnant healthy women [54]. Significantly higher IL17 levels have been reported in RM patients than in controls [45,55]. Sereshki et al (2014) also reported augmented IL17 levels in the proliferative and secretory phases of RM patients [41].…”