Simultaneous detection of decidual Th1/Th2 and NK1/NK2 immunophenotyping in unknown recurrent miscarriage using 8-color flow cytometry with FSC/Vt extended strategy

Identification of hub genes in placental dysfunction and recurrent pregnancy loss through transcriptome data mining: A meta-analysis

Recurrent pregnancy loss (RPL) is a condition characterized by the loss of two or more pregnancies before 20 weeks of gestation. The causes of RPL are complex and can be due to a variety of factors, including genetic, immunological, hormonal, and environmental factors. This transcriptome data mining study was done to explore the differentially expressed genes (DEGs) and related pathways responsible for pathogenesis of RPL using an Insilco approach. RNAseq datasets from the Gene Expression Omnibus (GEO) database was used to extract RNAseq datasets of RPL. Meta-analysis was done by ExpressAnalyst. The functional and pathway enrichment analysis of DEGs were performed using KEGG and BINGO plugin of Cytoscape software. Protein-protein interaction was done using STRING and hub genes were identified. A total of 91 DEGs were identified, out of which 10 were downregulated and 81 were upregulated. Pathway analysis indicated that majority of DEGs were enriched in immunological pathways (IL-17 signalling pathway, TLR-signalling pathway, autoimmune thyroid disease), angiogenic VEGF-signalling pathway and cell-cycle signalling pathways. Of these, 10 hub genes with high connectivity were selected (CXCL8, CCND1, FOS, PTGS2, CTLA4, THBS1, MMP2, KDR, and CD80). Most of these genes are involved in maintenance of immune response at maternal-fetal interface. Further, in functional enrichment analyses revealed the highest node size in regulation of biological processes followed by cellular processes, their regulation and regulation of multicellular organismal process. This in-silico transcriptomics meta-analysis findings could potentially contribute in identifying novel biomarkers and therapeutic targets for RPL, which could lead to the development of new diagnostic and therapeutic strategies for this condition.

High mobility group box 1 in women with unexplained recurrent pregnancy loss

OBJECTIVES

To investigate whether high mobility group box 1 (HMGB1) is involved in unexplained recurrent pregnancy loss (uRPL).

METHODS

Plasma levels of HMGB1 were measured by ELISA in non-pregnant women with (n=44) and without (n=53 controls) uRPL. Their platelets and plasma-derived microvesicles (MVs) were also assayed for HMGB1. Endometrial biopsies were taken in selected uRPL (n=5) and control women (n=5) and the tissue expression of HMGB1 was determined by western blot and immunohistochemistry (IHC).

RESULTS

plasma levels of HMGB1 were significantly higher in women with uRPL than in control women. HMGB1 content in platelets and MVs obtained from women with uRPL was significantly higher than that obtained from control women. HMGB1 expression in endometrium was higher in tissues obtained from women with uRPL than in tissues obtained from control women. IHC analysis revealed that HMGB1 is expressed in endometrium with different patterns between uRPL and control women.

CONCLUSIONS

HMGB1 could be involved in uRPL.

Efficacy and safety of Gushen Antai Pills combined with dydrogesterone in the treatment of threatened miscarriage: a systematic review and meta-analysis

Background: Despite some progress has been made in the pathogenesis and treatment of threatened miscarriage (TM), conventional treatment remains suboptimal. Thus, complementary medicine gradually become a new treatment option for treating threatened miscarriage. Gushen Antai Pills (GAP), a classic prescription of Traditional Chinese medicine (TCM), has became a popular complementary therapy to conventional western medicine (dydrogesterone) in treating threatened miscarriage in recent years. However, a systematic summary and analysis for its therapeutic effects is lacking. This meta-analysis aimed to systematically evaluate the effectiveness and safety of Gushen Antai Pills combined with dydrogesterone in the treatment of threatened miscarriage. Methods: A systematic search across seven electronic databases was conducted from inception to 17 September 2022. Studies were included if they were randomized controlled trials (RCTs) evaluating the effect of integrating Gushen Antai Pills and dydrogesterone in patients with threatened miscarriage, and reported the outcomes of interest. All statistical analyses were conducted using the Revman5.3 and Stata 13 software. The GRADE system was used to evaluate the quality of evidence. Results: Ten eligible randomized controlled trials involving 950 participants were contained in this meta-analysis. The pooled analysis showed that Gushen Antai Pills combined with dydrogesterone can significantly reduce the incidence of early pregnancy loss (RR: 0.29; 95% CI: 0.19-0.42; p < 0.00001) and alleviate clinical symptoms (RR: 1.39; 95% CI: 1.22-1.59; p < 0.00001), compared with treatment of dydrogesterone alone. Also, meta-analysis indicated that integrating Gushen Antai Pills and dydrogesterone is more effective than using dydrogesterone alone in improving hormone levels (serum levels of progesterone, β-HCG and estradiol) for women with threatened miscarriage (all p < 0.00001). Meanwhile, the combined effects with significant heterogeneity also showed favorable consistency in the sensitivity analyses, indicating a good stability of present results. Moreover, no significant differences between Gushen Antai Pills combined with dydrogesterone and control group on adverse events was identified. The overall GRADE qualities were low to moderate. Conclusion: The overall available evidence suggested that Gushen Antai Pills combined with dydrogesterone had significant effects in improving pregnancy success rate, clinical symptoms and hormone levels for women with threatened miscarriage, with considerable safety and reliability. However, due to the partial heterogeneity, suboptimal quality and high risk of bias of some included studies, further rigorously designed randomized controlled trials are required. Systematic Review Registration: identifier https://INPLASY2022120035, https://inplasy.com/inplasy-2022-12-0035/.

Immune phenotype of the endometrium in patients with recurrent implantation failures after the transfer of genetically tested embryos in assisted reproductive technology programs

Recurrent implantation failures (RIF) in assisted reproduction programs are one of the most challenging problems. Among the factors that can adversely affect implantation, endometrial immune structural disorders may be one of the leading causes. The aim of our work was to study the immune features of the endometrium in women with RIF after genetically tested embryo transfer in comparison with fertile gestational carriers. Immune cells in endometrial samples were studied by flow cytometry and RNA expression of IL (interleukin)15, IL18, fibroblast growth factor-inducible 14 receptor (Fn14), and tumor necrosis factor-like weak inducer of apoptosis (TWEAK) by reverse polymerase chain reaction. In one-third of the cases, a unique immune profile of the endometrium, which we called the not transformed endometrial immune phenotype, was found. It is characterized by a combination of features, such as high expression of HLA-DR on natural killers (NK), increased fraction of CD16 + , and a decreased fraction of CD56bright endometrial NK. In addition, when compared to gestational carriers, patients with RIF had a greater discrepancy between IL18 mRNA expression data, reduced mean TWEAK and Fn14 levels, and increased IL18/TWEAK and IL15/Fn14 ratios. Immune abnormalities that were found in more than half of the patients (66.7 %) may be the cause of implantation failures in genetically tested embryo transfer programs.

Recurrent Abortion and the Involvement of Killer-Cell Immunoglobulin-like Receptor (KIR) Genes, Activated T Cells, NK Abnormalities, and Cytokine Profiles

Immune tolerance at the feto-maternal interface is crucial for the growth of the semi-allograft fetus in the womb. The outcome of pregnancy is dependent on a fine balance between various immunological forces. For a long time, the potential role of the immune system in pregnancy disorders has remained enigmatic. Current evidence has revealed that natural killer (NK) cells are the predominant immune cell population in the uterine decidua. NK cells cooperate with T-cells to provide an optimal microenvironment for the growth of the developing fetus by producing cytokines, chemokines, and angiogenic factors. These factors support trophoblast migration and angiogenesis which regulates the process of placentation. NK cells differentiate between "self" and "non-self" through their surface receptors known as killer-cell immunoglobulin-like receptors (KIRs). They induce immune tolerance through communication via their KIR and fetal human leucocyte antigens (HLA). KIRs are surface receptors of NKs that comprise both activating and inhibiting receptors. Due to the wide diversity manifested by its genes, the KIR repertoire is different in each individual. Significant evidence has implicated KIRs in recurrent spontaneous abortion (RSA); however, maternal KIR gene diversity in RSA is still unclear. Research has shown that immunological aberrancies including activating KIRs, NK abnormalities, and T cell downregulation are risk factors for RSA. In this review, we discuss relevant data from experimental studies on NK cell abnormalities, KIR, and T-cells in the incidence of recurrent spontaneous abortion.

Cytokines, NK cells and regulatory T cell functions in normal pregnancy and reproductive failures

PURPOSE OF THE REVIEW

Pregnancy brings about an intricate assortment of dynamic changes, which causes proper connection of genetically discordant maternal and foetal tissues. Uterine NK cells are immune cells populating the endometrium and play a major role in implantation and also regulate placentation. This review mainly aims explore the role of uterine NK cells in implantation and how it is affecting in adverse pregnancy outcomes.

RECENT FINDINGS

Though the functions of uterine NK (uNK) cells are not clearly understood, NK cell activity plays a vital role during immunomodulation which is the main step in implantation and sustaining the early pregnancy. Cytokines, cell surface receptors of NK cells and hormones such as progesterone modulate the NK cell activity in turn affect the implantation of the embryo. Altered NK cell activity (number and functionality) would be an important attributing factor in adverse pregnancy outcomes. Furthermore, T regulatory cells and cytokines also modulate the immune responses in the decidua which in turn contributes to successful implantation of embryos.

SUMMARY

Immunological responses and interactions in the Foetus-maternal interface is crucial in the successful implantation of allogenic foetus resulting in a healthy pregnancy. NK cells, Treg cells and cytokines play a major role in successful implantation which remains an enigma. Comprehending pregnancy-induced immunological changes at the foetus-maternal interface will allow newer therapeutic strategies to improve pregnancy outcomes.

Uterine NK cells underexpress KIR2DL1/S1 and LILRB1 in reproductive failure

A significant proportion of recurrent miscarriage, recurrent implantation failure and infertility are unexplained, and these conditions have been proposed to have an etiology of immunological dysfunction at the maternal-fetal interface. Uterine Natural Killer cells (uNK) comprise three subsets and are the most numerous immune cells found in the uterine mucosa at the time of implantation. They are thought to play an important role in successful pregnancy by regulation of extravillous trophoblast (EVT) invasion and spiral artery remodelling. Here, we examine the frequency, phenotype and function of uNK1-3 from the uterine mucosa of 16 women with unexplained reproductive failure compared to 11 controls with no reproductive problems, during the window of implantation. We report that KIR2DL1/S1 and LILRB1 expression is lower in the reproductive failure group for both uNK (total uNK, uNK 2 and 3) and pNK. We also show that degranulation activity is significantly reduced in total uNK, and that TNF-α production is lower in all uNK subsets in the reproductive failure group. Taken together, our findings suggest that reproductive failure is associated with global reduction in expression of uNK receptors important for interaction with HLA-C and HLA-G on EVT during early pregnancy, leading to reduced uNK activation. This is the first study to examine uNK subsets during the window of implantation in women with reproductive failure and will serve as a platform to focus on particular aspects of phenotype and function of uNK subsets in future studies. Further understanding of uNK dysregulation is important to establish potential diagnostic and therapeutic targets in the population of women with unexplained reproductive failure.

Clinical Research into Treating Unexplained Recurrent Spontaneous Abortion during Early Pregnancy with the Qing Yi Tiao Mian Formula

OBJECTIVE

The present study aims to analyze the clinical effect of the Qing Yi Tiao Mian (QYTM) formula on unexplained recurrent spontaneous abortion (URSA) during early pregnancy and the immune balance of T lymphocytes.

METHODS

With their consent, 45 patients with URSA in weeks 4-9 of pregnancy were separated into three groups, i.e., the conventional fetal protection (n = 15), prednisone treatment (n = 10), and QYTM formula treatment (n = 20) groups. These patients received treatment once they had been diagnosed with an intrauterine pregnancy. The conventional fetal protection group was given progesterone (20 ∼ 40 mg daily injection) for four weeks. The prednisone treatment group was given progesterone (20 ∼ 40 mg daily injection) + prednisone (5 mg/d) for four weeks. The QYTM formula treatment group was given progesterone (20 ∼ 40 mg daily injection) + QYTM formula (one dose per day) for four weeks. In addition, women who had previously had a normal pregnancy were enrolled as a control group (n = 18). The success rate of the pregnancy in the first trimester was observed in each group, and the proportion of T lymphocytes in the peripheral blood before and after treatment was recorded.

RESULTS

Among the 20 patients with URSA in the QYTM formula treatment group, 19 remained pregnant. Thus, the success rate during early pregnancy was 95%, which was significantly higher than the conventional fetal protection (53.33%) and prednisone treatment (70%) groups. The CD8+ T and natural killer (NK) cells population in the URSA groups was higher compared with the control group (P < 0.01). The QYTM formula treatment significantly decreased the ratio of CD8+ T lymphocytes (P < 0.01) and NK cells (P < 0.01).

CONCLUSION

The QYTM formula significantly decreased the spontaneous abortion rate in patients with URSA during early pregnancy. The mechanism may be closely related to the inhibition of the killer lymphocytes' proliferation by CD8+ T lymphocytes and NK cells.

The Update Immune-Regulatory Role of Pro- and Anti-Inflammatory Cytokines in Recurrent Pregnancy Losses

Recurrent pregnancy losses (RPL) is a common reproductive disorder with various underlying etiologies. In recent years, rapid progress has been made in exploring the immunological mechanisms for RPL. A propensity toward Th2 over Th1 and regulatory T (Treg) over Th17 immune responses may be advantageous for reproductive success. In women with RPL and animals prone to abortion, an inordinate expression of cytokines associated with implantation and early embryo development is present in the endometrium or decidua secreted from immune and non-immune cells. Hence, an adverse cytokine milieu at the maternal-fetal interface assaults immunological tolerance, leading to fetal rejection. Similar to T cells, NK cells can be categorized based on the characteristics of cytokines they secrete. Decidual NK (dNK) cells of RPL patients exhibited an increased NK1/NK2 ratio (IFN-γ/IL-4 producing NK cell ratios), leading to pro-inflammatory cytokine milieu and increased NK cell cytotoxicity. Genetic polymorphism may be the underlying etiologies for Th1 and Th17 propensity since it alters cytokine production. In addition, various hormones participate in cytokine regulations, including progesterone and estrogen, controlling cytokine balance in favor of the Th2 type. Consequently, the intricate regulation of cytokines and hormones may prevent the RPL of immune etiologies. Local or systemic administration of cytokines or their antagonists might help maintain adequate cytokine milieu, favoring Th2 over Th1 response or Treg over Th17 immune response in women with RPL. Herein, we provided an updated comprehensive review regarding the immune-regulatory role of pro- and anti-inflammatory cytokines in RPL. Understanding the roles of cytokines involved in RPL might significantly advance the early diagnosis, monitoring, and treatment of RPL.

Number and function of uterine natural killer cells in recurrent miscarriage and implantation failure: a systematic review and meta-analysis

BACKGROUND

Uterine natural killer cells (uNK) are the most abundant lymphocytes found in the decidua during implantation and in first trimester pregnancy. They are important for early placental development, especially trophoblast invasion and transformation of the spiral arteries. However, inappropriate uNK function has been implicated in reproductive failure, such as recurrent miscarriage (RM) or recurrent implantation failure (RIF). Previous studies have mainly focussed on peripheral NK cells (pNK), despite the well-documented differences in pNK and uNK phenotype and function. In recent years, there has been an explosion of studies conducted on uNK, providing a more suitable representation of the immune environment at the maternal-foetal interface. Here, we summarize the evidence from studies published on uNK in women with RM/RIF compared with controls.

OBJECTIVE AND RATIONALE

The objectives of this systematic review and meta-analysis are to evaluate: differences in uNK level in women with RM/RIF compared with controls; pregnancy outcome in women with RM/RIF stratified by high and normal uNK levels; correlation between uNK and pNK in women with RM/RIF; and differences in uNK activity in women with RM/RIF compared with controls.

SEARCH METHODS

MEDLINE, EMBASE, Web of Science and Cochrane Trials Registry were searched from inception up to December 2020 and studies were selected in accordance with PRISMA guidelines. Meta-analyses were performed for uNK level, pregnancy outcome and uNK/pNK correlation. Narrative synthesis was conducted for uNK activity. Risk of bias was assessed by ROBINS-I and publication bias by Egger's test.

OUTCOMES

Our initial search yielded 4636 articles, of which 60 articles were included in our systematic review. Meta-analysis of CD56+ uNK level in women with RM compared with controls showed significantly higher levels in women with RM in subgroup analysis of endometrial samples (standardized mean difference (SMD) 0.49, CI 0.08, 0.90; P = 0.02; I2 88%; 1100 women). Meta-analysis of CD56+ uNK level in endometrium of women with RIF compared with controls showed significantly higher levels in women with RIF (SMD 0.49, CI 0.01, 0.98; P = 0.046; I2 84%; 604 women). There was no difference in pregnancy outcome in women with RM/RIF stratified by uNK level, and no significant correlation between pNK and uNK levels in women with RM/RIF. There was wide variation in studies conducted on uNK activity, which can be broadly divided into regulation and receptors, uNK cytotoxicity, cytokine secretion and effect of uNK on angiogenesis. These studies were largely equivocal in their results on cytokine secretion, but most studies found lower expression of inhibitory receptors and increased expression of angiogenic factors in women with RM.

WIDER IMPLICATIONS

The observation of significantly increased uNK level in endometrium of women with RM and RIF may point to an underlying disturbance of the immune milieu culminating in implantation and/or placentation failure. Further research is warranted to elucidate the underlying pathophysiology. The evidence for measuring pNK as an indicator of uNK behaviour is sparse, and of limited clinical use. Measurement of uNK level/activity may be more useful as a diagnostic tool, however, a standardized reference range must be established before this can be of clinical use.

Immunohistochemical Evaluation of CD3, CD4, CD8, and CD20 in Decidual and Trophoblastic Tissue Specimens of Patients with Recurrent Pregnancy Loss

Recurrent miscarriages affect up to 5% of couples. CD3⁺ (T-lymphocytes), CD4⁺ (helper T-lymphocytes), CD8⁺ (cytotoxic T-lymphocytes), and CD20⁺ (B-lymphocytes) cells may participate in the pathophysiology of recurrent pregnancy loss (RPL). The aim of this study was to investigate the complicity of these molecules in RPL. The experimental specimens were obtained from 20 females who underwent miscarriages in the first gestational trimester, while the control group’s specimens consisted of 20 females who proceeded with voluntary pregnancy termination during the same period. Tissue samples were taken from the decidua basalis, decidua parietalis, and trophoblast (placental chorionic villi) and were studied using immunohistochemical methods. Monoclonal antibodies were used against CD3, CD4, CD8, and CD20 cells. The lymphocyte levels in the decidua parietalis displayed profound disparities among the two groups. The decidua basalis and trophoblast exhibited almost the same disparities regarding positive CD cells. The comparison of CD4⁺ and CD8⁺ cells in the endometrial tissue revealed a significant difference between the two groups of study. The analysis uncovered a strong relationship between RPL and the presence of CD3⁺, CD4⁺, CD8⁺, and CD20⁺ cells in the decidua parietalis tissue. The number of positive T cells was decreased in the decidual basalis and chorionic villi, proving that their absence significantly disrupts the balance of the immunological environment.

The Role of Dendritic Cell Subsets in Recurrent Spontaneous Abortion and the Regulatory Effect of Baicalin on It

Recurrent spontaneous abortion (RSA) is a relevant complication of pregnancy. Aberrant dendritic cell (DC) activities and differentiation have been identified to be involved in RSA, but the underlying mechanisms remain unclear. Baicalin from Radix Scutellariae possesses a wide range of pharmacological and biological activities. However, the effect of baicalin on DC function in RSA has not been investigated. Here, we analyzed the changes of peripheral and maternal-fetal interface DC subsets and function in patients and mice with RSA, respectively. Then, we further treated RSA mice with baicalin and analyzed the therapeutic effect and underlying mechanism. We found that DCs from the peripheral blood and decidua of RSA patients and the maternal-fetal of RSA mice were all polarized to conventional DCs, whose proportion was positively correlated with the mice embryo absorption rate. Moreover, DCs from RSA patients and mice showed increased expression of HLA-DR/MHC-II, CD80, and CD86 but decreased expression of CD274 and 33D1. Importantly, baicalin could alleviate embryo resorption of RSA mice by reversing conventional DCs to plasmacytoid DCs and functional molecule expression via inhibiting the STAT5-ID2 pathway. Our research further proved that DCs play an important role in the pathogenesis of RSA and baicalin might be used for treating RSA.

The Role of Type I and Type II NKT Cells in Materno-Fetal Immunity

NKT cells represent a small but significant immune cell population as being a part of and bridging innate and adaptive immunity. Their ability to exert strong immune responses via cytotoxicity and cytokine secretion makes them significant immune effectors. Since pregnancy requires unconventional maternal immunity with a tolerogenic phenotype, investigation of the possible role of NKT cells in materno-fetal immune tolerance mechanisms is of particular importance. This review aims to summarize and organize the findings of previous studies in this field. Data and information about NKT cells from mice and humans will be presented, focusing on NKT cells characteristics during normal pregnancy in the periphery and at the materno-fetal interface and their possible involvement in female reproductive failure and pregnancy complications with an immunological background.

Relationship Between Pregnancy and Acute Disseminated Encephalomyelitis: A Single-Case Study

The relationship between pregnancy and autoimmune diseases is unclear. This study investigated the possible role of local immune changes and the activation state of the HMGB1/TLR4/Nf-κB/IL-6 pathway at the maternal–fetal interface during pregnancy in the pathogenesis of acute disseminated encephalomyelitis (ADEM). Clinical data and blood samples of a patient with ADEM were collected to observe the dynamic changes in lymphocyte populations after an abortion. The expression of HMGB1, TLR4, Nf-κB, AQP4, IL-2, IL-4, IL-6, and TNF-α in the fetal membrane and placenta was compared between the patient with pregnancy-related ADEM and a woman with a normal pregnancy using Real-time qPCR and western blotting (WB). The patient was diagnosed with ADEM in the early stage of pregnancy after showing limb weakness symptoms. In the third month of gestation, the symptoms worsened, with a disturbance of consciousness and breathing. After the abortion, the patient relapsed with vertigo and visual rotation. Analysis of lymphocyte subsets by flow cytometry showed that B lymphocytes increased, while natural killer T lymphocytes decreased. WB and Real-time qPCR showed that the expression levels of HMGB1, TLR4, Nf-κB, AQP4, and IL-6 in the fetal membrane and placenta were higher in the patient with pregnancy-related ADEM than in the woman with a normal pregnancy, while those of IL-2 were lower in the patient than in the woman with a normal pregnancy. The local immune changes and the activation of the HMGB1/TLR4/Nf-κB/IL-6 pathway at the maternal–fetal interface may be related to the pathogenesis of ADEM.

Expression of trophoblast derived prostaglandin E2 receptor 2 (EP2) is reduced in patients with recurrent miscarriage and EP2 regulates cell proliferation and expression of inflammatory cytokines

BACKGROUD

Prostaglandin E2 (PGE2), an inflammatory mediator, modulates cytokines, regulates immune responses in reproductive processes and stimulates inflammatory reactions via the prostaglandin E2 receptor 2 (EP2). However, the regulatory effects of EP2 signaling on trophoblasts and its role in unexplained recurrent miscarriage (uRM) remains unclear.

PATIENTS AND METHODS

A total of 19 placentas from patients with a history of more than two consecutive pregnancy losses of unknown cause (uRM group) and placentas of 19 healthy patients following a legal termination of their pregnancy were used for PGE2 receptor (EP1, EP2 and EP4) expression analyses via immunohistochemistry. Double immunofluorescence was also used to identify EP2 expressing cells in the decidua. Finally, HTR-8/SVneo cells were used to clarify the role of EP2 in in vitro experiments.

RESULTS

The expression of EP2 and EP4 was found to be reduced in the syncytiotrophoblast and decidua of uRM patients. A selective EP2 receptor antagonist (PF-04,418,948) reduced the proliferation and secretion of ß-hCG, inhibited interleukin -6 (IL-6) and interleukin-8 (IL-8) and up-regulated the production of the tumor necrosis factor-α (TNF-α) and plasminogen activator inhibitor type 1 (PAI-1) in HTR-8/SVneo cells in vitro.

CONCLUSION

PGE2-EP2 signaling pathway may represent a novel therapy option for uRM. The involvement of EP2 in uRM acts perhaps via inflammatory cytokines and indicates that the PGE2-EP2 signaling pathway might represent an unexplored etiology for uRM.

Natural killer cells in recurrent miscarriage: An overview

Recurrent Miscarriage is an early pregnancy complication which affects about 1-3 % of child-bearing couples. The mechanisms involved in the occurrence of recurrent miscarriages are not clearly understood. In the last decade Natural Killer cells have been studied in peripheral blood and uterus in order to determine if there are specific characteristics of Natural Killer cells associated with miscarriage. Different authors have described an increased number of uterine and peripheral blood Natural Killer cells in women with recurrent miscarriages compared to control women. However, its relationship with miscarriage has not been confirmed. In patients with recurrent miscarriage a lack of inhibition of decidua Natural Killer cells can be observed, which leads to a more activated state characterized by higher levels of proinflammatory cytokines. In peripheral blood, it has been also reported a dysfunctional cytokine production by Natural Killer cells, with an increase of interferon-γ levels and a decrease of Interleukin-4. Significant progress has been made in the last decade in understanding the biology of Natural Killer cells, including the identification of new receptors that also contribute to the activation and regulation of Natural Killer cells. In this review, we summarize the current progress in the study of Natural Killer cells in recurrent miscarriage.

Can neutrophil-to-lymphocyte and monocyte-to-lymphocyte ratios be useful markers for predicting missed abortion in the first trimester of pregnancy?

AIM

To explore whether neutrophil-to-lymphocyte ratio (NLR) and monocyte-to-lymphocyte ratio (MLR) could predict missed abortion (MA) at 7-13 week's gestation.

METHODS

A total of 363 women with a diagnosis of MA and 232 women with normal pregnancy at 7-13 week's gestation, who visited our hospital from June 2012 to May 2018 were retrospectively analyzed. At 7 week's gestation, total and differential leukocyte counts, NLR and MLR were compared between women with MA (n = 69) and normal controls (n = 53). The receiver operating characteristic curve was used to select the optimal indicator and its cut-off point. The role of the optimal indicator was further assessed at 8-13 week's gestation.

RESULTS

The mean white blood cell counts, the mean neutrophil counts, the median monocyte counts, the mean NLR and the median MLR in women with MA were significantly lower than those in normal controls (P < 0.05, respectively).The neutrophil counts had the highest area under the curve (AUC) value of 0.772 (95% confidence interval 0.675-0.869) with a cut-off value of 4.870 × 10⁹ /L, and the sensitivity was 72.46%, the specificity was 69.81%, positive predictive value was 75.76%, and negative predictive value was 66.07%. In addition, the neutrophil counts were also significantly lower in MA groups than those in normal controls at 8-13 week's gestation, and all had the highest AUC values.

CONCLUSION

Neutrophil counts may predict MA in the first trimester of pregnancy, which may provide a promising marker to diagnose missed abortion as early as 7 week's gestation.

Noncoding RNAs in Unexplained Recurrent Spontaneous Abortions and Their Diagnostic Potential

Unexplained recurrent spontaneous abortion (URSA) is defined as the loss of two or more consecutive pregnancies before the 20th week of gestation with normal findings on routine screening tests. Our understanding of the cellular and molecular pathogenesis of URSA is still far from complete. Noncoding RNAs (ncRNAs) play a pivotal role in transcription and expression. The functions of ncRNAs may also improve understanding of URSA pathogenesis. Because of their stability in the circulatory system and at the maternal-fetal interface, it may be possible to use ncRNAs as biomarkers for certain disease states. Here, we provide a narrative review of the current state of knowledge about ncRNAs associated with URSA. The possibility of developing a diagnostic tool using ncRNAs is discussed. The underlying mechanisms of how ncRNAs may lead to the onset of URSA are explored in this review.

Endometrial Immune Dysfunction in Recurrent Pregnancy Loss

Recurrent pregnancy loss (RPL) represents an unresolved problem for contemporary gynecology and obstetrics. In fact, it is not only a relevant complication of pregnancy, but is also a significant reproductive disorder affecting around 5% of couples desiring a child. The current knowledge on RPL is largely incomplete, since nearly 50% of RPL cases are still classified as unexplained. Emerging evidence indicates that the endometrium is a key tissue involved in the correct immunologic dialogue between the mother and the conceptus, which is a condition essential for the proper establishment and maintenance of a successful pregnancy. The immunologic events occurring at the maternal-fetal interface within the endometrium in early pregnancy are extremely complex and involve a large array of immune cells and molecules with immunoregulatory properties. A growing body of experimental studies suggests that endometrial immune dysregulation could be responsible for several, if not many, cases of RPL of unknown origin. The present article reviews the major immunologic pathways, cells, and molecular determinants involved in the endometrial dysfunction observed with specific application to RPL.

Decidualization modulates a signal transduction system via protease-activated receptor-1 in endometrial stromal cells

PROBLEM

Decidual cells are thought to be involved in the maintenance of pregnancy. We conducted this study to evaluate the cellular function of endometrial stromal cells (ESCs) transitioning to decidualization.

METHODS OF STUDY

Normal endometrial specimens were obtained from premenopausal patients who had undergone hysterectomies for subserosal leiomyomas. Decidualization of the ESCs (DSCs) was induced by incubating subconfluent cells in media containing medroxyprogesterone acetate and dibutyryl-cyclic adenosine monophosphate. We first analyzed the expression profile of protease-activated receptor-1 (PAR-1) between ESCs and DSCs. To investigate the intracellular signal transduction system in the DSCs, we incubated cells with thrombin receptor activator peptide 6 (TRAP-6). The levels of IL-8, monocyte chemo-attractant protein-1, matrix metalloproteinase (MMP)-1, and vascular endothelial growth factor in the culture medium were measured by enzyme-linked immunosorbent assays. The activation of the MAP kinase signaling pathway was detected by a Western blot analysis. The activation was evaluated for the expression of p21.

RESULTS

PAR-1 receptor expression is upregulated in DSCs. The productions of chemokine and MMP-1 increased in the DSCs with the addition of TRAP-6. The activity of both the ERK-1 and ERK-2 isoforms was increased by 5-15 minute after TRAP-6 treatment. p70 S6 kinase showed the strongest expression after 1 hour. p21 was strongly observed in ESCs compared to the DSCs.

CONCLUSION

Our results suggest that cell function is changed by decidualization in association with increasing PAR-1 expression. The upregulation of PAR-1 may have some influence on pregnancy in the decidua.

Obesity and recurrent miscarriage: A systematic review and meta-analysis

The aim of this study is to perform a systematic review and meta-analysis on the relationship between excess weight and risk of recurrent pregnancy loss (RPL) and to highlight the common immunological mechanisms of these two conditions. The PubMed and MEDLINE databases were searched for publications in English available as of November 2017. The search terms used were 'recurrent pregnancy loss', 'body mass index' (BMI), 'overweight' and 'obesity'. For calculation of the odds ratio (OR) and 95% confidence intervals (CI) for miscarriage in different BMI groups, RevMan software was used (Review Manager, Version 5.3.5 for Windows; The Cochrane Collaboration). In total, 100 publications including the search terms were identified. Six studies were included for qualitative analysis, and two studies were included for quantitative analysis (meta-analysis). The association between excess weight and RPL was significant (OR, 1.34; 95% CI, 1.05-1.70; P = 0.02). The isolated analyses of the groups of obese and overweight women revealed an association only between obesity and RPL (OR, 1.75; 95% CI, 1.24-2.47; P = 0.001). The data available in the current literature revealed that obese women with a history of RPL have a high risk of future pregnancy losses, a risk which was not found among overweight women.