Progesterone Modulation of Pregnancy-Related Immune Responses

Preterm birth, a consequence of immune deviation mediated hyperinflammation

Preterm birth represents a multifaceted syndrome with intricacies still present in our comprehension of its etiology. In the context of a semi-allograft, the prosperity from implantation to pregnancy to delivery hinges on the establishment of a favorable maternal-fetal immune microenvironment and a successful trilogy of immune activation, immune tolerance and then immune activation transitions. The occurrence of spontaneous preterm birth could be related to abnormalities within the immune trilogy, stemming from deviation in maternal and fetal immunity. These immune deviations, characterized by insufficient immune tolerance and early immune activation, ultimately culminated in an unsustainable pregnancy. In this review, we accentuated the role of both innate and adaptive immune reason in promoting spontaneous preterm birth, reviewed the risk of preterm birth from vaginal microbiome mediated by immune changes and the potential of vaginal microbiomes and metabolites as a new predictive marker, and discuss the changes in the role of progesterone and its interaction with immune cells in a preterm birth population. Our objective was to contribute to the growing body of knowledge in the field, shedding light on the immunologic reason of spontaneous preterm birth and effective biomarkers for early prediction, providing a roadmap for forthcoming investigations.

Progesterone modulates TNF receptors expression by Jurkat cells cultured with plasma from pregnant women with preeclampsia

Pregnant women with preeclampsia (PE) present a shift in the immune response to an inflammatory profile. This deviation could be due to the interaction of tumor necrosis factor (TNF) with TNFR1 and TNFR2 receptors, besides the failure in modulation of inflammation regulatory mechanisms. This study evaluated the effects of progesterone on the expression of TNFR1 and TNFR2 by Jurkat cells after stimulation with plasma from PE and normotensive (NT) pregnant women. Jurkat cells were cultured with or without progesterone in a medium containing 20% (v/v) plasma from PE or NT women. The expression of TNF receptors was evaluated by flow cytometry. The concentration of soluble forms of TNF receptors and cytokines was determined in culture supernatant and plasma by ELISA. The plasma of PE women showed significantly higher concentrations of sTNFR1 and TNF and lower concentrations of sTNFR2 compared to the NT group. TNFR1 receptor expression was increased in Jurkat cells, while TNFR2 was decreased after culture with PE plasma when compared with Jurkat cells cultured with progesterone and plasma from NT women. The concentration of sTNFR1, TNF, and IL-10 in the culture supernatant of Jurkat cells was increased after culture with PE plasma, while the sTNFR2 receptor was decreased when compared to the NT group. Results demonstrate that in preeclamptic women a systemic inflammation occurs with an increase of inflammatory molecules, and progesterone may have a modulating effect on the expression of TNF receptors, shifting Jurkat cells towards an anti-inflammatory profile with greater expression of TNFR2.

Antimicrobial stewardship and targeted therapies in the changing landscape of maternal sepsis

Pregnant and postnatal women are a high-risk population particularly prone to rapid progression to sepsis with significant morbidity and mortality worldwide. Moreover, severe maternal infections can have a serious detrimental impact on neonates with almost 1 million neonatal deaths annually attributed to maternal infection or sepsis. In this review we discuss the susceptibility of pregnant women and their specific physiological and immunological adaptations that contribute to their vulnerability to sepsis, the implications for the neonate, as well as the issues with antimicrobial stewardship and the challenges this poses when attempting to reach a balance between clinical care and urgent treatment. Finally, we review advancements in the development of pregnancy-specific diagnostic and therapeutic approaches and how these can be used to optimize the care of pregnant women and neonates.

Comparing the peri-implantation endometrial T-bet/GATA3 ratio between control fertile women and patients with recurrent miscarriage: establishment and application of a reference range

STUDY QUESTION

Is the ratio of endometrial T-box expressed in T cell (T-bet) and GATA-binding protein 3 (GATA3) changed in patients with recurrent miscarriage (RM) compared to fertile controls?

SUMMARY ANSWER

Our study showed a significantly higher T-bet/GATA3 ratio in patients with RM compared with fertile controls.

WHAT IS KNOWN ALREADY

The endometrial T-bet (Th1 lineage-committed transcription factor)/GATA3 (Th2 lineage-committed transcription factor) ratio could represent the Th1/Th2 balance, which is particularly important for healthy pregnancy. However, a reliable reference range for the T-bet/GATA3 ratio during the peri-implantation period has not yet been established for use in clinical practice.

STUDY DESIGN, SIZE, DURATION

This was a retrospective study carried out in a private fertility center. The control group included 120 women in couples undergoing IVF treatment for male infertility, who had experienced a live-birth baby following the first IVF cycle. The study group included 93 women diagnosed with RM that experienced at least two consecutive clinically spontaneous miscarriages before gestational week 12. The ratio of T-bet/GATA3 was calculated in the control group and RM group.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Endometrium samples were collected at mid-luteal phase of the menstrual cycle prior to IVF treatment or pregnancy. The percentage of T-bet+ and GATA3+ cells in total endometrial cells was analyzed using immunohistochemical staining and quantitative analysis.

MAIN RESULTS AND THE ROLE OF CHANCE

Using the 95th percentile to define the upper limits of the endometrial T-bet/GATA3 ratio during the mid-luteal phase, the reference range of control fertile women was ≤0.22. Compared with the control group, the RM group exhibited a significantly higher T-bet/GATA3 ratio (P = 0.02), and 19.4% (18/93) women with RM exhibited a T-bet/GATA3 ratio above the reference range in the mid-luteal phase.

LIMITATIONS, REASONS FOR CAUTION

All patients were recruited from a single center. The stability and clinical value of the endometrial T-bet/GATA3 ratio require further investigation.

WIDER IMPLICATIONS OF THE FINDINGS

The present study suggests that an abnormal endometrial T-bet/GATA3 ratio may be one of the risk factors of RM. Further studies are needed to follow up the pregnancy outcomes in patients with RM with normal and abnormal endometrial T-bet/GATA3 ratio according to the reference range.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by Shenzhen Fundamental Research Program (JCYJ20180228164631121, JCYJ20190813161203606, JCYJ20220530172817039). There are no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Characterization of progesterone-induced dendritic cells in metabolic and immunologic reprogramming

The role of maternal-fetal immune tolerance in the establishment and maintenance of pregnancy has been well established. Dendritic cells (DCs) as a crucial part of the decidual microenvironment, have high plasticity in immunogenicity and tolerogenicity. The regulatory mechanisms of DCs phenotype or function at the maternal-fetal interface, however, have not been fully developed. Studies from the field of immunometabolism have highlighted that the metabolic pathways of DCs are closely associated with their immunity. Our previous study showed that progesterone (P4) up-regulated a series of enzymes involved in DCs mitochondrial oxidative phosphorylation and fatty acid metabolism. In this study, we confirmed that P4 induced significant alternations in DCs metabolic pathways, promoting their glycolysis, mitochondrial function, and the dependency and capacity of fatty acids as mitochondrial fuel. Moreover, P4 also increased the inhibitory molecule ILT4 expression on DCs and down-regulated the CD86, which may coordinate their immune tolerance function in pregnancy. Together, our study helps to understand the role of P4 in DCs metabolic and immunologic reprogramming and may provide novel insights into the hormonal immunometabolism regulation of DCs during normal pregnancy.

Progress on the Role of Estrogen and Progesterone Signaling in Mouse Embryo Implantation and Decidualization

Embryo implantation and decidualization are key steps in establishing a successful pregnancy. Defects in embryo implantation and decidualization can cause a series of adverse chain reactions which can contribute to harmful pregnancy outcomes, such as embryo growth retardation, preeclampsia, miscarriage, premature birth, and so on. Approximately 75% of failed pregnancies are considered to be due to embryo implantation failure or defects. Decidualization, characterized by proliferation and differentiation of uterine stromal cells, is one of the essential conditions for blastocyst implantation, placental formation, and maintenance of pregnancy and is indispensable for the establishment of pregnancy in many species. Embryo implantation and decidualization are closely regulated by estrogen and progesterone secreted by the ovaries. Many cellular events and molecular signaling network pathways are involved in this process. This article reviews the recent advances in the molecular mechanisms of estrogen- and progesterone-regulating uterine receptivity establishment, blastocyst implantation, and decidualization, in order to better understand the underlying molecular mechanisms of hormonal regulation of embryo implantation and to develop new strategies for preventing or treating embryo implantation defects and improving the pregnancy rate of women.

Postpartum hepatitis and host immunity in pregnant women with chronic HBV infection

In order to develop immune tolerant to the fetal, maternal immune system will have some modification comparing to the time before pregnancy. Immune tolerance starts and develops at the maternal placental interface. In innate immunity, decidual natural killer (dNK) cells, macrophages and dendritic cells play a key role in immue tolerance. In adaptive immunity, a moderate increase of number and immune inhibition function of regulatory T cells (Treg) are essential for immune tolerance. The trophoblast cells and immune cells expressing indoleamine 2,3-dioxygenase (IDO), the trophoblast cells expressing HLA-G, and Th1/Th2 shifting to Th2 dominant and Th17/Treg shifting to Treg domiant are in favor of maternal fetal immune tolerance. Steroids (estrogen and progesterone) and human chorionic gonadotropin (HCG) also participate in immune tolerance by inducing Treg cells or upregulating immunosuppressive cytokines. Most of the patients with chronic HBV infection are in the "HBV immune tolerance period" before pregnancy, and the liver disease is relatively stable during pregnancy. In chronic HBV infection women, after delivery, the relative immunosuppression in vivo is reversed, and Th1 is dominant in Th1/Th2 and Th17 is dominant in Th17/Treg balance. After delivery, the number of Treg decrease and NK cells increase in quantity and cytotoxicity in peripheral blood. Liver NK cells may cause liver inflammation through a non-antigen specific mechanism. After delivery, the number of CD8⁺ T cells will increase and HBV specific T cell response recovers from the disfunction in pregnancy. Under the background of postpartum inflammation, the rapid decrease of cortisol after delivery, and especially the enhancement of HBV specific T cell response induced by HBV DNA and cytokines, are the main reasons for postpartum hepatitis. HBeAg positive, especially HBeAg<700 S/CO, and HBV DNA>3-5Log₁₀IU/ml are risk factors for postpartum hepatitis. Antiviral treatment in late pregnancy can reduce the incidence of mother to child transmission (MTCT) in chronic HBV infection women. Chronic HBV infection women have hepatitis both during pregnancy and more often in 12 weeks postpartum. It is generally agreed that postpartum hepatitis is mild symptoms and self-limited. Delaying drug withdrawal to 48 weeks can increase the seroconversion rate of HBeAg in delivery women with elevated alanine aminotransferase (ALT) in pregnancy.

Effects of biological sex and pregnancy in experimental autoimmune encephalomyelitis: It's complicated

Experimental autoimmune encephalomyelitis (EAE) can be induced in many animal strains by inoculation with central nervous system antigens and adjuvant or by the passive transfer of lymphocytes reactive with these antigens and is widely used as an animal model for multiple sclerosis (MS). There are reports that female sex and pregnancy affect EAE. Here we review the effects of biological sex and the effects of pregnancy on the clinical features (including disease susceptibility) and pathophysiology of EAE. We also review reports of the possible mechanisms underlying these differences. These include sex-related differences in the immune system and in the central nervous system, the effects of hormones and the sex chromosomes and molecules unique to pregnancy. We also review sex differences in the response to factors that can modify the course of EAE. Our conclusion is that the effects of biological sex in EAE vary amongst animal models and should not be widely extrapolated. In EAE, it is therefore essential that studies looking at the effects of biological sex or pregnancy give full information about the model that is used (i.e. animal strain, sex, the inducing antigen, timing of EAE induction in relation to pregnancy, etc.). In addition, it would be preferable if more than one EAE model were used, to show if any observed effects are generalizable. This is clearly a field that requires further work. However, understanding of the mechanisms of sex differences could lead to greater understanding of EAE, and suggest possible therapies for MS.

Clinical factors associated with low serum progesterone levels on the day of frozen blastocyst transfer in hormonal replacement therapy cycles

STUDY QUESTION

Which factors are associated with low serum progesterone (P) levels on the day of frozen embryo transfer (FET), in HRT cycles?

SUMMARY ANSWER

BMI, parity and non-European geographic origin are factors associated with low serum P levels on the day of FET in HRT cycles.

WHAT IS KNOWN ALREADY

The detrimental impact of low serum P concentrations on HRT-FET outcomes is commonly recognized. However, the factors accounting for P level disparities among patients receiving the same luteal phase support treatment remain to be elucidated, to help clinicians predicting which subgroups of patients would benefit from a tailored P supplementation.

STUDY DESIGN, SIZE, DURATION

Observational cohort study with 915 patients undergoing HRT-FET at a tertiary care university hospital, between January 2019 and March 2020.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Patients undergoing single autologous blastocyst FET under HRT using exogenous estradiol and vaginal micronized progesterone for endometrial preparation. Women were only included once during the study period. The serum progesterone level was measured in the morning of the FET, in a single laboratory. Independent factors associated with low serum P levels (defined as ≤9.8 ng/ml, according to a previous published study) were analyzed using univariate and multivariate logistic regression models.

MAIN RESULTS AND THE ROLE OF CHANCE

Two hundred and twenty-six patients (24.7%) had a low serum P level, on the day of the FET. Patients with a serum P level ≤9.8 ng/ml had a lower live birth rate (26.1% vs 33.2%, P = 0.045) and a higher rate of early miscarriage (35.2% vs 21.5%, P = 0.008). Univariate analysis showed that BMI (P < 0.001), parity (P = 0.001), non-European geographic origin (P = 0.001), the duration of infertility (P = 0.018) and the use of oral estradiol for endometrial preparation (P = 0.009) were significantly associated with low serum P levels. Moreover, the proportion of active smokers was significantly lower in the 'low P concentrations' group (P = 0.002). After multivariate analysis, BMI (odds ratio (OR) 1.06 95% CI (1.02-1.11), P = 0.002), parity (OR 1.32 95% CI (1.04-1.66), P = 0.022), non-European geographic origin (OR 1.70 95% CI (1.21-2.39), P = 0.002) and active smoking (OR 0.43 95% CI (0.22-0.87), P = 0.018) remained independent factors associated with serum P levels ≤9.8 ng/ml.

LIMITATIONS, REASONS FOR CAUTION

The main limitation of this study is its observational design, leading to a risk of selection and confusion bias that cannot be ruled out, although a multivariable analysis was performed to minimize this.

WIDER IMPLICATIONS OF THE FINDINGS

Extrapolation of our results to other laboratories, or other routes and/or doses of administering progesterone also needs to be validated. There is urgent need for future research on clinical factors affecting P concentrations and the underlying pathophysiological mechanisms, to help clinicians in predicting which subgroups of patients would benefit from individualized luteal phase support.

STUDY FUNDING/COMPETING INTEREST(S)

No funding/no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Progesterone modulates CD4+ CD25+ FoxP3+ regulatory T Cells and TGF-β1 in the maternal-fetal interface of the late pregnant mouse

OBJECTIVE

Progesterone supplementation is recommended to prevent spontaneous preterm birth (sPTB) in clinical practice. However, the exact mechanism is still unclear. This study aims to better understand the mechanisms that progesterone can prevent PTB.

METHODS

Late pregnant mice were given various doses of progesterone receptor antagonist mifepristone, and pregnancy outcomes were observed. Then, non-pregnant and pregnant mice were given a subcutaneous injection of 40 mg/kg progesterone and 5 mg/kg mifepristone, respectively. CD4⁺ CD25⁺ FoxP3⁺ Treg cells in peripheral blood and decidua basalis were detected by FACS. Expressions of FoxP3 and TGF-β1 in the decidua basalis were detected.

RESULTS

Mifepristone induced preterm birth, and an obvious dose-response was found. Proportions of CD4⁺ CD25⁺ FoxP3⁺ Treg cells in the peripheral blood of non-pregnant mice increased significantly after progesterone injection. CD4⁺ CD25⁺ FoxP3⁺ Treg cells in the peripheral blood of pregnant mice increased significantly compared with those of non-pregnant mice. In pregnant mice, mifepristone significantly decreased the proportions of CD4⁺ CD25⁺ FoxP3⁺ Treg cells in peripheral blood, and reduced proportions of Treg cells at the maternal-fetal interface and expressions of FoxP3 and TGF-β1 in the maternal-fetal interface. Total 40 mg/kg of progesterone did not increase CD4⁺ CD25⁺ FoxP3⁺ Treg in the peripheral blood of pregnant mice, but increased proportions of Treg cells at the maternal-fetal interface and up-regulated FoxP3 and TGF-β1 expressions in the maternal-fetal interface.

CONCLUSION

Progesterone promotes pregnancy immune homeostasis by up-regulating Treg cells and TGF-β1 expression in the maternal-fetal interface. It may be one of the mechanisms of progesterone in preventing sPTB.

Progesterone and Inflammatory Response in the Oviduct during Physiological and Pathological Conditions

Progesterone has been shown to be a potent suppressor of several inflammatory pathways. During pregnancy, progesterone levels increase, allowing for normal pregnancy establishment and maintenance. The dysregulation of progesterone, as well as inflammation, leads to poor pregnancy outcomes. However, it is unclear how progesterone imbalance could impact inflammatory responses in the oviduct and subsequently result in early pregnancy loss. Therefore, in this review, we describe the role of progesterone signaling in regulating the inflammatory response, with a focus on the oviduct and pathological conditions in the Fallopian tubes.

The risk of intrauterine exposure to SARS-CoV-2 in female COVID-19 patients: A comprehensive review

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is a new type of coronavirus that has caused fatal infectious diseases and global spread. This novel coronavirus attacks target cells through the interaction of spike protein and angiotensin‐converting enzyme II (ACE2), leading to different clinical symptoms. However, for a successful pregnancy, a well‐established in‐uterine environment includes a specific immune environment, and multi‐interactions between specific cell types are prerequisites. The immune‐related changes in patients infected with novel coronavirus could interfere with the immune microenvironment in the uterus, leading to fetal loss. We first reviewed the intrauterine environment in the normal development process and the possible pregnancy outcome in the infection state. Then, we summarized the immune response induced by SARS‐CoV‐2 in patients and analyzed the changes in ACE2 expression in the female reproductive system. Finally, the present observational evidence of infection in pregnant women was also reviewed.

How neuroactive factors mediates immune responses during pregnancy: An interdisciplinary view

Pregnancy, from insemination to parturition, is a highly complex but well-orchestrated process that requires various organs and systems to participate. Immune system and neuroendocrine system are important regulators in healthy pregnancy. Dozens of neuroactive factors have been detected in human placenta, whether they are locally secreted or circulated. Among them, some are vividly studied such as corticotropin-releasing hormone (CRH), human chorionic gonadotropin (hCG), transforming growth factor-β (TGF-β), progesterone and estrogens, while others are relatively lack of research. Though the neuroendocrine-immune interactions are demonstrated in some diseases for decades, the roles of neuroactive factors in immune system and lymphocytes during pregnancy are not fully elucidated. This review aims to provide an interdisciplinary view on how the neuroendocrine system mediate immune system during pregnancy process.

The effect of progesterone administration on the expression of metastasis tumor antigens (MTA1 and MTA3) in placentas of normal and dexamethasone-treated rats

BACKGROUND

Dexamethasone (DEX) induces intrauterine growth restriction (IUGR) in pregnant rats. IUGR can occur due to apoptosis of trophoblasts, which is believed to be inhibited by progesterone (P4). A group of genes called MTAs play a role in proliferation and apoptosis. MTA1 upregulates trophoblasts proliferation and differentiation, while MTA3 downregulates proliferation and induces apoptosis. Hence, we hypothesized that during IUGR, placental MTA1 decreases and MTA3 increases and this is reversed by P4 treatment.

METHODS

Pregnant Sprague-Dawley rats were divided into 4 groups based on daily intraperitoneal injections: control (C, saline), DEX (DEX, 0.2 mg/kg/day), DEX and P4 (DEX + P4, DEX: 0.2 mg/kg/day, P4: 5 mg/kg/day) and P4-treated (P4, 5 mg/kg/day) groups. Injections were started on 15 dg until the day of dissection (19 or 21 dg). Gene and protein expressions of MTA1 and MTA3 were studied in the labyrinth (LZ) and basal (BZ) zones using real-time PCR and Western blotting, respectively.

RESULTS

DEX treatment induced 18% reduction in fetal body weight (p < 0.001) and 30% reduction in placental weight (p < 0.01). Maternal P4 level was also significantly lower in DEX treated groups (p < 0.05). MTA1 expression was decreased in the LZ (gene, p < 0.001) and BZ (protein p < 0.01), while MTA3 protein expression was upregulated in the LZ with DEX treatment (p < 0.001). These changes were reversed with P4 treatment.

CONCLUSION

The findings of the present study indicate that DEX induces IUGR through changing the expression of placental MTA1 and MTA3 antigens and P4 improved pregnancy outcome by preventing the changes in MTAs expression.

Identification of Profound Metabolic Alterations in Human Dendritic Cells by Progesterone Through Integrated Bioinformatics Analysis

Maintaining the homeostasis of the decidual immune microenvironment at the maternal-fetal interface is essential for reproductive success. Dendritic cells (DCs) are the professional antigen-presenting cells and dominate this balance of immunogenicity and tolerance. Progesterone (P4) is highlighted as the “hormone of pregnancy” in most eutherian mammals because of its regulatory role in immune-endocrine behavior during pregnancy. Recent studies have shown that P4 is associated with the differentiation and function of DCs, however, the underlying mechanisms remain unidentified. In addition, while progress in the field of immunometabolism has highlighted the intimate connections between the metabolism phenotype and the immunogenic or tolerogenic fate of DCs, whether P4 can affect DCs metabolism and thus exert a functional manipulation has not yet been explored. In this study, we acquired human peripheral blood monocyte-derived DCs and conducted RNA sequencing (RNA-seq) on immature DCs (iDCs), P4-treated DCs (pDCs), and mature DCs (mDCs), aiming to comprehensively assess the effects of P4 on DCs. Our results showed pDCs performed a distinct differentially expressed genes (DEGs) profile compared with iDCs or mDCs. Further functional enrichment and weighted gene co-expression network (WGCNA) analysis found that these DEGs were related not only to the cellular components but also to the significant metabolic activities, including mitochondrial oxidative phosphorylation (OXPHOS) and fatty acid metabolism. In addition, these changes may be involved in the activation of various signaling pathways of PI3K/Akt/mTOR, AMPK/PGC1-α, and PPAR-γ. In summary, our work suggested that P4 induced profound metabolic alterations of mitochondrial OXPHOS and fatty acid metabolism in DCs. Our findings may provide new insights into the role of P4 in DCs.

Low serum progesterone affects live birth rate in cryopreserved blastocyst transfer cycles using hormone replacement therapy

RESEARCH QUESTION

Does serum progesterone concentration on the day of vitrified-warmed embryo transfer affect live birth rate (LBR) with hormonal replacement therapy (HRT) cycles?

DESIGN

Observational cohort study of patients (n = 915) undergoing single autologous vitrified-warmed blastocyst transfer under HRT using vaginal micronized progesterone. Women were included once, between January 2019 and March 2020. Serum progesterone concentration was measured by a single laboratory on the morning of embryo transfer. The primary end point was LBR. Univariate and multivariate logistic regression models were used for statistical analyses.

RESULTS

Median (25th-75th percentile) serum progesterone concentration on the day of embryo transfer was 12.5 ng/ml (9.8-15.3). The LBR was 31.5% (288/915) in the overall population. No significant differences were found in implantation rates (40.7% versus 44.9%); LBR was significantly lower in women with a progesterone concentration ≤25th percentile (≤9.8 ng/ml) (26.1% versus 33.2%, P = 0.045) versus women with a progesterone concentration >25th percentile. This correlated with a significantly higher early miscarriage rate (35.9% versus 21.6%, P = 0.005). After adjusting for potential confounding factors in multivariate analysis, low serum progesterone levels (≤9.8 ng/ml) remained significantly associated with lower LBR (OR 0.68 95% CI 0.48 to 0.97).

CONCLUSION

A minimum serum progesterone concentration is needed to optimize reproductive outcomes in HRT cycles with single autologous vitrified-warmed blastocyst transfer. Whether modifications of progesterone administration routes, dosage, or both, can improve pregnancy rates needs further study so that treatment of patients undergoing HRT cycles can be further individualized.

A Potential Three-Gene-Based Diagnostic Signature for Hypertension in Pregnancy

Background

Hypertensive disorders of pregnancy affect approximately 5–10% of all pregnancies, and this study aims to identify potential diagnostic signatures.

Methods

We downloaded the mRNA profiles of GSE75010 (placenta samples) and GSE48424 (blood samples) datasets with or without hypertension in pregnancy from the Gene Expression Omnibus database. Differential expression analysis was performed on the placenta samples using limma package of R language. GO terms and KEGG pathways enrichment analyses were performed on the placenta samples by the clusterProfiler package of R language. Infiltrating immune cell proportion of the placenta samples was evaluated using CIBERSORT software. The key genes involved in hypertension in pregnancy were screened from protein–protein interaction (PPI) network constructed based on the differentially expressed genes (DEGs). The logistic regression model was constructed by the glm package of R language, and receiver operating characteristic (ROC) curve was plotted to determine the accuracy of the model.

Results

For the placenta samples, a total of 104 DEGs were identified, and 39 GO terms and 7 KEGG pathways were significantly enriched based on these 104 genes. Furthermore, the analysis of infiltrating immune cells indicated that the difference in the amount of immune cells might be the potential cause of hypertension in pregnancy. The logistic regression model was constructed based on three optimal genes (LEP, PRL and IGFBP1) screened from PPI network and could efficiently separate patients with hypertension in pregnancy from healthy subjects.

Conclusion

A predictive model based on three potential genes LEP, PRL and IGFBP1 was obtained, suggesting that these genes might be potential diagnostic signatures for hypertension in pregnancy.

Maternal Immune Activation Hypotheses for Human Neurodevelopment: Some Outstanding Questions

The Maternal Immune Activation (MIA) hypothesis is a leading model for understanding prenatal influences on individual differences in, and clinical syndromes of, neurodevelopment. Experimental animal and human research has proliferated in recent years, and there is now a sizable research base. Several meta-analyses demonstrate general support for an association between prenatal immune activation and neurodevelopment in human research. However, questions remain about the nature of the immune activation, the network of underlying mechanisms involved, and the breadth of impact across behavioral phenotypes. Complementing recent reviews of results, the current review places particular emphasis on how advances in understanding mechanisms may be improved with greater attention to addressing the methodological variation and limitations of existing studies, and identifies areas for further clinical research.

Biologia futura: embryo-maternal communication via progesterone-induced blocking factor (PIBF) positive embryo-derived extracellular vesicles. Their role in maternal immunomodulation

Paternal antigens expressed by the foetus are recognized as foreign. Therefore,-according to the rules of transplantation immunity-the foetus ought to be "rejected". However, during normal gestation, maternal immune functions are re-adjusted, in order to create a favourable environment for the developing foetus. Some of the mechanisms that contribute to the altered immunological environment, for example, the cytokine balance and NK cell function, with special emphasis on the role of progesterone and the progesterone-induced blocking factor (PIBF) will be reviewed.

Progesterone-induced blocking factor (PIBF) influences the expression of membrane progesterone receptors (mPRs) on peripheral CD4+ T lymphocyte cells in normal fertile females

PURPOSE

Progesterone-induced blocking factor (PIBF) is a protein secreted by lymphocytes exposed to progesterone (P4). P4 and PIBF have immunomodulatory effects on peripheral CD4⁺ T cells during normal pregnancy. Membrane progesterone receptors (mPRs) may correlate with the immunomodulatory properties of P4 on T cells. Variation in expression of mPRs may influence P4 regulatory performance during pregnancy. On the other hand, PIBF increases in pregnant normal women compared to women who have experienced abortion. The present study aimed to determine whether PIBF, in addition to having a direct influence on the immune system, can affect P4 performance through its effect on mPR expression. Such novel research findings demonstrate the importance of PIBF in the maintenance of pregnancy.

METHODS

Isolated peripheral blood mononuclear cells (PBMCs) from 30 healthy women were stimulated with the mitogen phytohemagglutinin (PHA). Cells were either exposed to various concentrations of PIBF or had no exposure at all in a culture medium at 37 °C for 3 days. The mean fluorescence intensity (MFI) of mPRα and mPRβ was evaluated using polyclonal and monoclonal antibodies on CD4⁺ T cells.

RESULTS

PIBF was able to significantly increase mPR expression on the surface of peripheral CD4⁺ T cells (p ≤ 0.05).

CONCLUSION

This study characterized the effects of PIBF on mPR expression on peripheral CD4⁺ T cells of healthy fertile women. Thus, a decrease in PIBF concentration during abnormal pregnancy can modulate mPR expression and regulatory performance of P4 on T cells. Future research into this issue is likely to open up a new understanding of the etiology of abortion.

Cytokines, Hormones and Cellular Regulatory Mechanisms Favoring Successful Reproduction

Its semi-allogeneic nature renders the conceptus vulnerable to attack by the maternal immune system. Several protective mechanisms operate during gestation to correct the harmful effects of anti-fetal immunity and to support a healthy pregnancy outcome. Pregnancy is characterized by gross alterations in endocrine functions. Progesterone is indispensable for pregnancy and humans, and it affects immune functions both directly and via mediators. The progesterone-induced mediator - PIBF - acts in favor of Th2-type immunity, by increasing Th2 type cytokines production. Except for implantation and parturition, pregnancy is characterized by a Th2-dominant cytokine pattern. Progesterone and the orally-administered progestogen dydrogesterone upregulate the production of Th2-type cytokines and suppress the production of Th1 and Th17 cytokine production in vitro. This is particularly relevant to the fact that the Th1-type cytokines TNF-α and IFN-γ and the Th17 cytokine IL-17 have embryotoxic and anti-trophoblast activities. These cytokine-modulating effects and the PIBF-inducing capabilities of dydrogesterone may contribute to the demonstrated beneficial effects of dydrogesterone in recurrent spontaneous miscarriage and threatened miscarriage. IL-17 and IL-22 produced by T helper cells are involved in allograft rejection, and therefore could account for the rejection of paternal HLA-C-expressing trophoblast. Th17 cells (producing IL-17 and IL-22) and Th22 cells (producing IL-22) exhibit plasticity and could produce IL-22 and IL-17 in association with Th2-type cytokines or with Th1-type cytokines. IL-17 and IL-22 producing Th cells are not harmful for the conceptus, if they also produce IL-4. Another important protective mechanism is connected with the expansion and action of regulatory T cells, which play a major role in the induction of tolerance both in pregnant women and in tumour-bearing patients. Clonally-expanded Treg cells increase at the feto-maternal interface and in tumour-infiltrating regions. While in cancer patients, clonally-expanded Treg cells are present in peripheral blood, they are scarce in pregnancy blood, suggesting that fetal antigen-specific tolerance is restricted to the foeto-maternal interface. The significance of Treg cells in maintaining a normal materno-foetal interaction is underlined by the fact that miscarriage is characterized by a decreased number of total effector Treg cells, and the number of clonally-expanded effector Treg cells is markedly reduced in preeclampsia. In this review we present an overview of the above mechanisms, attempt to show how they are connected, how they operate during normal gestation and how their failure might lead to pregnancy pathologies.

Mifepristone inhibited the expression of B7-H2, B7-H3, B7-H4 and PD-L2 in adenomyosis

BACKGROUND

The immune mechanism was shown to be involved in the development of adenomyosis. The aim of the current study was to evaluate the expression of the immune checkpoints B7-H2, B7-H3, B7-H4 and PD-L2 in adenomyosis and to explore the effect of mifepristone on the expression of these immune checkpoints.

METHODS

The expression of B7-H2, B7-H3, B7-H4 and PD-L2 in normal endometria and adenomyosis patient samples treated with or without mifepristone was determined by immunohistochemistry analysis.

RESULTS

In adenomyosis patient samples, the expression of B7-H2, B7-H3 and B7-H4 was increased in the eutopic and ectopic endometria compared with normal endometria, both in the proliferative and secretory phases. Moreover, the expression of B7-H2 and B7-H3 was higher in adenomyotic lesions than in the corresponding eutopic endometria, both in the proliferative and secretory phases. The expression of PD-L2 was higher in adenomyotic lesions than in normal endometria in both the proliferative and secretory phases. In the secretory phase but not the proliferative phase, the expression of B7-H4 and PD-L2 in adenomyotic lesions was significantly higher than that in the corresponding eutopic endometria. In normal endometria and eutopic endometria, the expression of B7-H4 was elevated in the proliferative phase compared with that in the secretory phase, while in the ectopic endometria, B7-H4 expression was decreased in the proliferative phase compared with the secretory phase. In addition, the expression of B7-H2, B7-H3, B7-H4 and PD-L2 was significantly decreased in adenomyosis tissues after treatment with mifepristone.

CONCLUSIONS

The expression of the immune checkpoint proteins B7-H2, B7-H3, B7-H4 and PD-L2 is upregulated in adenomyosis tissues and is downregulated with mifepristone treatment. The data suggest that B7 immunomodulatory molecules are involved in the pathophysiology of adenomyosis.

Differential effects of estradiol and progesterone on human T cell activation in vitro

Estradiol (E2) and progesterone (P4) are steroid hormones important for the regulation of immune responses during pregnancy. Their increasing levels coincide with an improvement of T cell-mediated diseases such as multiple sclerosis (MS). Although immune-endocrine interactions are involved in this phenomenon, the relative contribution of hormones is not known. We here report a direct comparison of E2- and P4-mediated effects on human CD4⁺ T cells, key cells in immune regulation. T cells were stimulated to obtain different activation levels and exposed to a broad range of hormone concentrations. Activation level was assessed by CD69/CD25 expression by flow cytometry, and secreted proteins (n = 196) were measured in culture supernatants using proximity extension assay and electrochemiluminescence immunoassay. We found that in low activated cells, pregnancy-relevant E2 concentrations increased activation and the secretion of several immune- and inflammation-related proteins. P4, on the other hand, showed a biphasic pattern, where serum-related concentrations upregulated activation and protein secretion while placenta-relevant concentrations induced a prominent dampening irrespective of the initial activation level. Our results demonstrate the importance of P4 as a major hormone in the immune modulation of T cells during pregnancy and emphasize the need to further evaluate its potency in the treatment of diseases like MS.

Is there a link between plasma progesterone 1-2 days before frozen embryo transfers (FET) and ART outcomes in frozen blastocyst transfers?

OBJECTIVE

To study the efficacy of combined administration of subcutaneous and vaginal progesterone for priming frozen blastocysts transfers, looking at progesterone levels and ART outcome.

DESIGN

Retrospective study.

SETTING PATIENTS

Three hundred and twenty frozen blastocyst transfer cycles conducted in 213 women aged up to 42 years, BMI between 18 and 30 kg/m², with anatomically normal uterus who underwent frozen embryo transfers (FETs) from February 2019 to December 2019 with a combined luteal-phase support (LPS) associating subcutaneous and vaginal progesterone. Patients with recurrent pregnancy loss (RPL) were excluded.

RESULTS

When using combined vaginal and subcutaneous LPS, SPL >10.50 ng/mL in 95% of cases, with a minimum value of 7.02 ng/mL. CPR, OPR, and global miscarriage rates were 38.4%, 30.9%, and 19.5%, respectively. Analyzing results per quartiles, revealed that miscarriage rates were significantly inferior, and IR were higher in the upper two quartiles of serum progesterone (>21.95 ng/mL) on the day before FET, while there was no difference in CPR and OPR.

CONCLUSIONS

We report ART outcome of frozen blastocyst transfers performed using a combination of vaginal and subcutaneous progesterone for LPS. ART results were honorable and SPL favorable 1-2 days before FET in 99% of cases.

Impact of low serum progesterone levels on the day of embryo transfer on pregnancy outcome: a prospective cohort study in artificial cycles with vaginal progesterone

STUDY QUESTION

Is there a serum progesterone (P) threshold on the day of embryo transfer (ET) in artificial endometrium preparation cycles below which the chances of ongoing pregnancy are reduced?

SUMMARY ANSWER

Serum P levels <8.8 ng/ml on the day of ET lower ongoing pregnancy rate (OPR) in both own or donated oocyte cycles.

WHAT IS KNOWN ALREADY

We previously found that serum P levels <9.2 ng/ml on the day of ET significantly decrease OPR in a sample of 211 oocyte donation recipients. Here, we assessed whether these results are applicable to all infertile patients under an artificial endometrial preparation cycle, regardless of the oocyte origin.

STUDY DESIGN, SIZE, DURATION

This prospective cohort study was performed between September 2017 and November 2018 and enrolled 1205 patients scheduled for ET after an artificial endometrial preparation cycle with estradiol valerate and micronized vaginal P (MVP, 400 mg twice daily).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Patients ≤50 years old with a triple-layer endometrium ≥6.5 mm underwent transfer of one or two blastocysts. A total of 1150 patients treated with own oocytes without preimplantation genetic testing for aneuploidies (PGT-A) (n = 184), own oocytes with PGT-A (n = 308) or donated oocytes (n = 658) were analyzed. The primary endpoint was the OPR beyond pregnancy week 12 based on serum P levels measured immediately before ET.

MAIN RESULTS AND THE ROLE OF CHANCE

Women with serum P levels <8.8 ng/ml (30th percentile) had a significantly lower OPR (36.6% vs 54.4%) and live birth rate (35.5% vs 52.0%) than the rest of the patients. Multivariate logistic regression showed that serum P < 8.8 ng/ml was an independent factor influencing OPR in the overall population and in the three treatment groups. A significant negative correlation was observed between serum P levels and BMI, weight and time between the last P dose and blood tests and a positive correlation was found with age, height and number of days on HRT. Multivariate logistic regression showed that only body weight was an independent factor for presenting serum P levels <8.8 ng/ml. Obstetrical and perinatal outcomes did not differ in patients with ongoing pregnancy regardless of serum P levels being above/below 8.8 ng/ml.

LIMITATIONS, REASONS FOR CAUTION

Only women with MVP were included. Extrapolation to other P administration forms needs to be validated.

WIDER IMPLICATIONS OF THE FINDINGS

This study identified the threshold of serum P as 8.8 ng/ml on the day of ET for artificial endometrial preparation cycles necessary to optimize outcomes, in cycles with own or donated oocytes. One-third of patients receiving MVP show inadequate levels of serum P that, in turn, impact the success of the ART cycle. Monitoring P levels in the mid-luteal phase is recommended when using MVP to adjust the doses according to the needs of the patient.

STUDY FUNDING/COMPETING INTEREST(S)

None.

TRIAL REGISTRATION NUMBER

NCT03272412.

Supraphysiological estradiol promotes human T follicular helper cell differentiation and favours humoural immunity during in vitro fertilization

During pregnancy, humoural immunity is essential for protection against many extracellular pathogens; however, autoimmune diseases may be induced or aggravated. T follicular helper (Tfh) cells contribute to humoural immunity. The aim of this study was to test whether Tfh cell function can be manipulated via hormones. Seventy‐four women who underwent in vitro fertilization were recruited and divided into four groups: menstrual period (MP), controlled ovarian hyperstimulation (COH), embryo transfer (ET) and pregnant after embryo transfer (P). A flow cytometry analysis was performed to identify Tfh cells in peripheral blood mononuclear cells (PBMCs). Bioinformatics analysis revealed a possible pathway between Tfh and B cells. Enzyme‐linked immunosorbent assays were used to detect interleukin (IL)‐21 and IL‐6. The quantitative polymerase chain reaction was performed to quantify BCL‐6, BACH2, XBP‐1, IRF‐4 and G protein‐coupled (GP)ER‐1 mRNA expression. Compared with the MP group, the COH, ET and P groups showed more Tfh and B cells, as well as higher IL‐21, IL‐6, BCL‐6 and BACH2 expression. Furthermore, Tfh cell frequency in PBMCs, as well as serum IL‐21 and IL‐6 levels, were all positively correlated with serum estradiol (E₂) levels; the B cell percentage also correlated positively with Tfh cells in PBMCs. Combined with the bioinformatics analysis, XBP‐1, IRF‐4 and GPER‐1 expression was related to E₂ levels, both in vivo and in vitro. We speculate that E₂ augments Tfh cells and favours humoural immunity. This study indicates that Tfh cell regulation may be a novel target in maintaining the maternal‐foetal immune balance.

Progesterone Dampens Immune Responses in In Vitro Activated CD4+ T Cells and Affects Genes Associated With Autoimmune Diseases That Improve During Pregnancy

The changes in progesterone (P4) levels during and after pregnancy coincide with the temporary improvement and worsening of several autoimmune diseases like multiple sclerosis (MS) and rheumatoid arthritis (RA). Most likely immune-endocrine interactions play a major role in these pregnancy-induced effects. In this study, we used next generation sequencing to investigate the direct effects of P4 on CD4⁺ T cell activation, key event in pregnancy and disease. We report profound dampening effects of P4 on T cell activation, altering the gene and protein expression profile and reversing many of the changes induced during the activation. The transcriptomic changes induced by P4 were significantly enriched for genes associated with diseases known to be modulated during pregnancy such as MS, RA and psoriasis. STAT1 and STAT3 were significantly downregulated by P4 and their downstream targets were significantly enriched among the disease-associated genes. Several of these genes included well-known and disease-relevant cytokines, such as IL-12β, CXCL10 and OSM, which were further validated also at the protein level using proximity extension assay. Our results extend the previous knowledge of P4 as an immune regulatory hormone and support its importance during pregnancy for regulating potentially detrimental immune responses towards the semi-allogenic fetus. Further, our results also point toward a potential role for P4 in the pregnancy-induced disease immunomodulation and highlight the need for further studies evaluating P4 as a future treatment option.

Progesterone promotes immunomodulation and tumor development in the murine mammary gland

BACKGROUND

Clinical studies have linked usage of progestins (synthetic progesterone [P4]) to breast cancer risk. However, little is understood regarding the role of native P4, signaling through the progesterone receptor (PR), in breast tumor formation. Recently, we reported a link between PR and immune signaling pathways, showing that P4/PR can repress type I interferon signaling pathways. Given these findings, we sought to investigate whether P4/PR drive immunomodulation in the mammary gland and promote tumor formation.

METHODS

To determine the effect of P4 on immune cell populations in the murine mammary gland, mice were treated with P4 or placebo pellets for 21 days. Immune cell populations in the mammary gland, spleen, and inguinal lymph nodes were subsequently analyzed by flow cytometry. To assess the effect of PR overexpression on mammary gland tumor development as well as immune cell populations in the mammary gland, a transgenic mouse model was used in which PR was overexpressed throughout the entire mouse. Immune cell populations were assessed in the mammary glands, spleens, and inguinal lymph nodes of 6-month-old transgenic and control mice by flow cytometry. Transgenic mice were also monitored for mammary gland tumor development over a 2-year time span. Following development of mammary gland tumors, immune cell populations in the tumors and spleens of transgenic and control mice were analyzed by flow cytometry.

RESULTS

We found that mice treated with P4 exhibited changes in the mammary gland indicative of an inhibited immune response compared with placebo-treated mice. Furthermore, transgenic mice with PR overexpression demonstrated decreased numbers of immune cell populations in their mammary glands, lymph nodes, and spleens. On long-term monitoring, we determined that multiparous PR-overexpressing mice developed significantly more mammary gland tumors than control mice. Additionally, tumors from PR-overexpressing mice contained fewer infiltrating immune cells. Finally, RNA sequencing analysis of tumor samples revealed that immune-related gene signatures were lower in tumors from PR-overexpressing mice as compared with control mice.

CONCLUSION

Together, these findings offer a novel mechanism of P4-driven mammary gland tumor development and provide rationale in investigating the usage of antiprogestin therapies to promote immune-mediated elimination of mammary gland tumors.

COVID-19 During Development: A Matter of Concern

A new infectious disease, COVID-19, has spread around the world. The most common symptoms of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are cough and fever, but severe cases can develop acute respiratory distress syndrome. The main receptor for SARS-CoV-2 in human tissue is angiotensin-converting enzyme 2, and the lungs, heart, and kidneys are the most affected organs. Besides the inflammatory process and tissue damage, the presence of a cytokine "storm" has been related to a higher mortality rate. Other infectious viral diseases, such as Zika, chikungunya, and influenza, were associated with complications in pregnant women, such as growth restriction, malformation, preterm birth, low birth weight, miscarriage, and death, although they can also cause developmental disorders in infants and adolescents. Evidence points out that stressors during pregnancy and infancy may lead to the development of obesity, diabetes, and cardiovascular disease. Therefore, we hypothesize that COVID-19 infection during the critical phases of development can program the individual to chronic diseases in adulthood. It is important that COVID-19 patients receive proper monitoring as a way to avoid expensive costs to public health in the future.

Progesterone and vitamin D downregulate the activation of the NLRP1/NLRP3 inflammasomes and TLR4-MyD88-NF-κB pathway in monocytes from pregnant women with preeclampsia

This study evaluated the in vitro modulatory effect of progesterone (PG) and vitamin D (VD) on NLRP1/NLRP3 inflammasomes and TLR4/NF-κB pathway in monocytes from pregnant women with preeclampsia (PE). Monocytes from 20 preeclamptic and 20 normotensive (NT) pregnant women, and THP-1 cells were cultured with/without hyaluronan (HA), PG, or VD to determine gene and protein expression of TLR4 receptor, phosphorylated NF-κB, IκBα, TLR4, MYD88, NF-κB, NLRP1, NLRP3, caspase-1, IL-1β, IL-18, TNF-α, and IL-10. Higher endogenous activation of inflammatory genes and higher protein expression of TLR4 and NF-κB was detected in monocytes of PE group and decreased after PG or VD treatment. Monocyte from PE stimulated with HA increased while treatment with PG or VD decreased the expression of genes and proteins related to the inflammasomes. THP-1 cells showed a similar immune response profile as monocytes from PE. These results demonstrate that PG and VD play an immunomodulatory role in monocyte activation.

Using the Immune System to Manage Immunologically-Mediated Pregnancy Loss

Pregnancy is not nearly as successful as laypersons might assume, challenged as it is by several complications such as threatened abortion, spontaneous miscarriage, preeclampsia, and preterm delivery, among others. The maternal immune system has been shown to contribute to the etiopathogenesis of some of these pregnancy complications. Pro-inflammatory and anti-inflammatory cytokines have been studied for their effects on pregnancy because of their powerful and versatile effects on cells and tissues. This review addresses the relationship between pro-inflammatory cytokines and recurrent miscarriage, which is an important complication of pregnancy. References for this review were identified by using PRISMA-IPD (Preferred Reporting Items for a Systematic Review and Meta-analysis of Individual Participant Data) Guidelines by conducting searches for published articles from January 1, 1990 until March 1, 2020 in the following databases: PubMed, Google Scholar, and MEDLINE via OVID by the use of the search terms “recurrent spontaneous miscarriage,” “cytokines,” “progesterone,” “progestogen,” “dydrogesterone,” and “immunomodulation.” This review also presents the proposed mechanisms of action of pro-inflammatory cytokines in pregnancy loss, and then goes on to discuss the modulation of cytokine profiles to a state that is favorable to the success of pregnancy. In addition to its indispensable endocrinologic role of progesterone in pregnancy, it also has some intriguing immunomodulatory capabilities. We then summarize studies that show that progesterone and dydrogesterone, an orally-administered progestogen, suppress the production of pro-inflammatory cytokines and enhance the production of anti-inflammatory cytokines before mentioning clinical studies on progestogen supplementation. These studies support the contention that progestogens should be explored for the immunotherapeutic management of pregnancy complications.

Human pregnancy levels of estrogen and progesterone contribute to humoral immunity by activating TFH /B cell axis

Circulating T_FH (cT_FH ) cells express CXCR5, PD-1, and, when activated, ICOS, and release IL-21. According to the production of IFN-γ, IL-4, and IL-17 and expression of FoxP3, these cells are also classified as cT_FH 1, cT_FH 2, cT_FH 17, and cT_FR cells, respectively. This CD4⁺ T-cell subset is pivotal to efficient humoral immunity, and pregnancy appears to favor IgG production. Here, not only pregnancy amplified the in vivo production of anti-HBsAg IgG in HBV immunized women, but the frequency of cT_FH cells was directly correlated with estradiol levels. In vitro, pregnancy-related dose of 17-β-estradiol (E2) directly increased the percentage of different cT_FH subsets. While E2 and progesterone (P4) increased the proportion of differentiated T_FH cells derived from naïve CD4⁺ T-cells, only E2 amplified the release of IL-21 in those cell cultures. In addition, E2 and P4 increased the proportion of memory B cells and plasma cells, respectively. In SEB-activated B/T_FH cell co-cultures, E2, in the presence of P4, increased the production of total IgG. Finally, among the hormones, P4 was stronger in upregulating the percentage of IL-10⁺ T_FR cells. Collectively, our findings suggested that E2 and P4 cooperate in the humoral immune response by favoring the expansion of different cT_FH and B cell subsets.

Innate Immune Responses to Acute Viral Infection During Pregnancy

Immunological adaptations in pregnancy allow maternal tolerance of the semi-allogeneic fetus but also increase maternal susceptibility to infection. At implantation, the endometrial stroma, glands, arteries and immune cells undergo anatomical and functional transformation to create the decidua, the specialized secretory endometrium of pregnancy. The maternal decidua and the invading fetal trophoblast constitute a dynamic junction that facilitates a complex immunological dialogue between the two. The decidual and peripheral immune systems together assume a pivotal role in regulating the critical balance between tolerance and defense against infection. Throughout pregnancy, this equilibrium is repeatedly subjected to microbial challenge. Acute viral infection in pregnancy is associated with a wide spectrum of adverse consequences for both mother and fetus. Vertical transmission from mother to fetus can cause developmental anomalies, growth restriction, preterm birth and stillbirth, while the mother is predisposed to heightened morbidity and maternal death. A rapid, effective response to invasive pathogens is therefore essential in order to avoid overwhelming maternal infection and consequent fetal compromise. This sentinel response is mediated by the innate immune system: a heritable, highly evolutionarily conserved system comprising physical barriers, antimicrobial peptides (AMP) and a variety of immune cells—principally neutrophils, macrophages, dendritic cells, and natural killer cells—which express pattern-receptors that detect invariant molecular signatures unique to pathogenic micro-organisms. Recognition of these signatures during acute infection triggers signaling cascades that enhance antimicrobial properties such as phagocytosis, secretion of pro-inflammatory cytokines and activation of the complement system. As well as coordinating the initial immune response, macrophages and dendritic cells present microbial antigens to lymphocytes, initiating and influencing the development of specific, long-lasting adaptive immunity. Despite extensive progress in unraveling the immunological adaptations of pregnancy, pregnant women remain particularly susceptible to certain acute viral infections and continue to experience mortality rates equivalent to those observed in pandemics several decades ago. Here, we focus specifically on the pregnancy-induced vulnerabilities in innate immunity that contribute to the disproportionately high maternal mortality observed in the following acute viral infections: Lassa fever, Ebola virus disease (EVD), dengue fever, hepatitis E, influenza, and novel coronavirus infections.

The Effect of Mung Bean (Vigna radiata (L.)) Coat Extract on Mouse Liver Metabolism During Progesterone Withdrawal

Mung bean (Vigna radiata) is an immunomodulatory medicinal plant, which is recognized as a component of a traditional postpartum diet. The liver plays a crucial role in fatty acid synthesis under the control of various hormones that are affected by pregnancy. This study was designed to establish whether the mung bean water extract, which contains prostaglandins that can regulate corpus luteum maturation, provided any benefits to liver metabolism after the dynamic hormonal change associated with pregnancy. Female C57BL/6J mice were used, and all mice received daily injections of progesterone (5.0 mg/kg) for 5 days, after which progesterone was withdrawn for 3 days. Gel-free/label-free proteomic analysis revealed that the abundance of several proteins was affected in the liver. Hormone manipulation induced changes in lipid metabolism-related protein abundance; oral administration of mung bean coat extract (MBC) for 3 days mitigated the changes and downregulated the expression of Cpt1α, Akr1β, and Srebp1 in the liver. Together with immunological leukocyte modulation assessed via proteomic analysis, we suggest that MBC may exert health-promoting effects through the modulation of lipid synthesis during postpartum recovery.

Effects of Pregnancy and Isoniazid Preventive Therapy on M. tuberculosis Interferon Gamma Response Assays in Women with HIV

BACKGROUND

Pregnancy is accompanied by immune suppression. We hypothesized that M. tuberculosis-specific inflammatory responses used to identify latent tuberculosis infection (LTBI) lose positivity during pregnancy. We also hypothesized that isoniazid preventive therapy (IPT) may revert LTBI diagnoses because of its sterilizing activity.

METHODS

944 women with HIV participating in a randomized, double-blind, placebo-controlled study comparing 28 weeks of IPT antepartum versus postpartum, were tested by QuantiFERON-gold-in-tube (QGIT) antepartum and by QGIT and tuberculin skin test (TST) at delivery and postpartum. Serial QGIT positivity was assessed by logistic regression using generalized estimating equations.

RESULTS

From entry to delivery, 68 (24%) of 284 QGIT-positive women (24%) reverted to QGIT-negative or indeterminate. Of these, 42 (62%) recovered QGIT positivity postpartum. The loss of QGIT positivity during pregnancy was explained by decreased IFNγ production in response to TB antigen and/or mitogen. At delivery, QGIT identified 205 and TST 113 women with LTBI. Corresponding numbers postpartum were 229 and 122 women. QGIT and TST kappa agreement coefficients were 0.4 and 0.5, respectively. Among QGIT-positive women antepartum or at delivery, 34 (12%) reverted to QGIT-negative after IPT. There were no differences between women who initiated IPT antepartum or postpartum.

CONCLUSIONS

Decreased IFNγ responses in pregnancy reduced QGIT positivity, suggesting that this test cannot reliably rule out LTBI during pregnancy. TST was less affected by pregnancy, but had lower positivity compared to QGIT at all time points. IPT was associated with loss of QGIT positivity, the potential clinical consequences of which need to be investigated.

Inhibition of the NLRP3 inflammasome can prevent sterile intra-amniotic inflammation, preterm labor/birth, and adverse neonatal outcomes†

Sterile intra-amniotic inflammation is commonly observed in patients with spontaneous preterm labor, a syndrome that commonly precedes preterm birth, the leading cause of perinatal morbidity and mortality worldwide. However, the mechanisms leading to sterile intra-amniotic inflammation are poorly understood and no treatment exists for this clinical condition. Herein, we investigated whether the alarmin S100B could induce sterile intra-amniotic inflammation by activating the NLRP3 inflammasome, and whether the inhibition of this pathway could prevent preterm labor/birth and adverse neonatal outcomes. We found that the ultrasound-guided intra-amniotic administration of S100B induced a 50% rate of preterm labor/birth and a high rate of neonatal mortality (59.7%) without altering the fetal and placental weights. Using a multiplex cytokine array and immunoblotting, we reported that S100B caused a proinflammatory response in the amniotic cavity and induced the activation of the NLRP3 inflammasome in the fetal membranes, indicated by the upregulation of the NLRP3 protein and increased release of active caspase-1 and mature IL-1β. Inhibition of the NLRP3 inflammasome via the specific inhibitor MCC950 prevented preterm labor/birth by 35.7% and reduced neonatal mortality by 26.7%. Yet, inhibition of the NLRP3 inflammasome at term did not drastically obstruct the physiological process of parturition. In conclusion, the data presented herein indicate that the alarmin S100B can induce sterile intra-amniotic inflammation, preterm labor/birth, and adverse neonatal outcomes by activating the NLRP3 inflammasome, which can be prevented by inhibiting such a pathway. These findings provide evidence that sterile intra-amniotic inflammation could be treated by targeting the NLRP3 inflammasome.

Functional significance of lymphocytes in pregnancy and lymphocyte immunotherapy in infertility: A comprehensive review and update

During pregnancy, the fetal-maternal interface underlies several dynamic alterations to permit the fetus to be cultivated and developed in the uterus, in spite of being identifies by the maternal immune system. A large variety of decidual leukocyte populations, including natural killer cells, NKT cells, innate lymphoid cells, dendritic cells, B cells, T cells, subpopulations of helper T cells play a vital role in controlling the trophoblast invasion, angiogenesis as well as vascular remodeling. In contrast, several regulatory immunosuppressive mechanisms, including regulatory T cells, regulatory B cells, several cytokines and mediators are involved in maintain the homeostasis of immune system in the fetal-maternal interface. Nonetheless, aberrant alterations in the balance of immune inflammatory or immunosuppressive arms have been associated with various pregnancy losses and infertilities. As a result, numerous strategies have been developed to revers dysregulated balance of immune players to increase the chance of successful pregnancy. Lymphocyte immunotherapy has been developed through utilization of peripheral white blood cells of the husband or others and administered into the mother to confer an immune tolerance for embryo's antigens. However, the results have not always been promising, implying to further investigations to improve the approach. This review attempts to clarify the involvement of lymphocytes in contributing to the pregnancy outcome and the potential of lymphocyte immunotherapy in treatment of infertilities with dysregulated immune system basis.

SeXX Matters in Multiple Sclerosis

Multiple sclerosis (MS) is the most common chronic inflammatory and neurodegenerative disease of the central nervous system (CNS). An interesting feature that this debilitating disease shares with many other inflammatory disorders is that susceptibility is higher in females than in males, with the risk of MS being three times higher in women compared to men. Nonetheless, while men have a decreased risk of developing MS, many studies suggest that males have a worse clinical outcome. MS exhibits an apparent sexual dimorphism in both the immune response and the pathophysiology of the CNS damage, ultimately affecting disease susceptibility and progression differently. Overall, women are predisposed to higher rates of inflammatory relapses than men, but men are more likely to manifest signs of disease progression and worse CNS damage. The observed sexual dimorphism in MS may be due to sex hormones and sex chromosomes, acting in parallel or combination. In this review, we outline current knowledge on the sexual dimorphism in MS and discuss the interplay of sex chromosomes, sex hormones, and the immune system in driving MS disease susceptibility and progression.

Visualization of materials using the confocal laser scanning microscopy technique

The development of materials science always benefits from advanced characterizations. Currently, imaging techniques are of great technological importance in both fundamental and applied research on materials. In comparison to conventional visualization methods, confocal laser scanning microscopy (CLSM) is non-invasive, with macroscale and high-contrast scanning, a simple and fast sample preparation procedure as well as easy operation. In addition, CLSM allows rapid acquisition of longitudinal and cross-sectional images at any position in a material. Therefore, the CLSM-based visualization technique could provide direct and model-independent insight into material characterizations. This review summarizes the recent applications of CLSM in materials science. The current CLSM approaches for the visualization of surface structures, internal structures, spatial structures and reaction processes are discussed in detail. Finally, we provide our thoughts and predictions on the future development of CLSM in materials science. The purpose of this review is to guide researchers to build a suitable CLSM approach for material characterizations, and to open viable opportunities and inspirations for the development of new strategies aiming at the preparation of advanced materials. We hope that this review will be useful for a wide range of research communities of materials science, chemistry, and engineering.

Human labour is associated with altered regulatory T cell function and maternal immune activation

During human pregnancy, regulatory T cell (T_reg ) function is enhanced and immune activation is repressed allowing the growth and development of the feto-placental unit. Here, we have investigated whether human labour is associated with a reversal of the pregnancy-induced changes in the maternal immune system. We tested the hypothesis that human labour is associated with a decline in T_reg function, specifically their ability to modulate Toll-like receptor (TLR)-induced immune responses. We studied the changes in cell number, activation status and functional behaviour of peripheral blood, myometrial (myoMC) and cord blood mononuclear cells (CBMC) with the onset of labour. We found that T_reg function declines and that T_reg cellular targets change with labour onset. The changes in T_reg function were associated with increased activation of myoMC, assessed by their expression of major histocompatibility complex (MHC) class II molecules and CBMC inflammatory cells. The innate immune system showed increased activation, as shown by altered monocyte and neutrophil cell phenotypes, possibly to be ready to respond to microbial invasion after birth or to contribute to tissue remodelling. Our results highlight changes in the function of the adaptive and innate immune systems that may have important roles in the onset of human labour.

Sepsis: Precision-Based Medicine for Pregnancy and the Puerperium

Sepsis contributes significantly to global morbidity and mortality, particularly in vulnerable populations. Pregnant and recently pregnant women are particularly prone to rapid progression to sepsis and septic shock, with 11% of maternal deaths worldwide being attributed to sepsis. The impact on the neonate is considerable, with 1 million neonatal deaths annually attributed to maternal infection or sepsis. Pregnancy specific physiological and immunological adaptations are likely to contribute to a greater impact of infection, but current approaches to the management of sepsis are based on those developed for the non-pregnant population. Pregnancy-specific strategies are required to optimise recognition and management of these patients. We review current knowledge of the physiology and immunology of pregnancy and propose areas of research, which may advance the development of pregnancy-specific diagnostic and therapeutic approaches to optimise the care of pregnant women and their babies.

Single-cell technologies in reproductive immunology

The maternal-fetal interface represents a unique immune privileged site that maintains the ability to defend against pathogens while orchestrating the necessary tissue remodeling required for placentation. The recent discovery of novel cellular families (innate lymphoid cells, tissue-resident NK cells) suggests that our understanding of the decidual immunome is incomplete. To understand this complex milieu, new technological developments allow reproductive immunologists to collect increasingly complex data at a cellular resolution. Polychromatic flow cytometry allows for greater resolution in the identification of novel cell types by surface and intracellular protein. Single-cell RNA-seq coupled with microfluidics allows for efficient cellular transcriptomics. The extreme dimensionality and size of data sets generated, however, requires the application of novel computational approaches for unbiased analysis. There are now multiple dimensionality reduction (tSNE, SPADE) and visualization tools (SPICE) that allow researchers to efficiently analyze flow cytometry data. Development of computational tools has also been extended to RNA-seq data (including scRNA-seq), which requires specific analytical tools. Here, we provide an overview and a brief primer for the reproductive immunology community on data acquisition and computational tools for the analysis of complex flow cytometry and RNA-seq data.

Pregnancy-related immune suppression leads to altered influenza vaccine recall responses

Pregnancy is a risk factor for severe influenza infection. Despite achieving seroprotective antibody titres post immunisation fewer pregnant women experience a reduction in influenza-like illness compared to non-pregnant cohorts. This may be due to the effects that immune-modulation in pregnancy has on vaccine efficacy leading to a less favourable immunologic response. To understand this, we investigated the antigen-specific cellular responses and leukocyte phenotype in pregnant and non-pregnant women who achieved seroprotection post immunisation. We show that pregnancy is associated with better antigen-specific inflammatory (IFN-γ) responses and an expansion of central memory T cells (Tcm) post immunisation, but low-level pregnancy-related immune regulation (HLA-G, PIBF) and associated reduced B-cell antibody maintenance (TGF-β) suggest poor immunologic responses compared to the non-pregnant. Thus far, studies of influenza vaccine immunogenicity have focused on the induction of antibodies but understanding additional vaccine-related cellular responses is needed to fully appreciate how pregnancy impacts on vaccine effectiveness.

Progestogens and immunology

Fifty percent of fetal antigens are of paternal origin. These are recognized by the maternal immune system, thereby resulting in lymphocyte activation and the induction of progesterone receptors (PRs) in immune cells. Upon binding of progesterone to PRs on lymphocytes, a downstream mediator called progesterone-induced blocking factor (PIBF) is produced. The full-length PIBF is a 90 kDa protein; however, because of alternative splicing, several smaller isoforms are also produced. While the 90 kDa molecule plays a role in cell cycle regulation, the small isoforms are localized in the cytoplasm, and after secretion, they bind to their receptors on other cells and act in a cytokine-like manner. The communication between the embryo and the maternal immune system is established through PIBF-containing extracellular vesicles. PIBF induces an increased production of Th2 cytokines and inhibits degranulation of NK cells, and by regulating the maternal immune response, it contributes to successful implantation and maintenance of pregnancy.

Progesterone-Related Immune Modulation of Pregnancy and Labor

Pregnancy involves a complex interplay between maternal neuroendocrine and immunological systems in order to establish and sustain a growing fetus. It is thought that the uterus at pregnancy transitions from quiescent to laboring state in response to interactions between maternal and fetal systems at least partly via altered neuroendocrine signaling. Progesterone (P4) is a vital hormone in maternal reproductive tissues and immune cells during pregnancy. As such, P4 is widely used in clinical interventions to improve the chance of embryo implantation, as well as reduce the risk of miscarriage and premature labor. Here we review research to date that focus on the pathways through which P4 mediates its actions on both the maternal reproductive and immune system. We will dissect the role of P4 as a modulator of inflammation, both systemic and intrinsic to the uterus, during human pregnancy and labor.

Activation of CCL20 and its receptor CCR6 promotes endometrium preparation for implantation and placenta development during the early pregnancy period in pigs

The success of implantation and placentation during early pregnancy depends on the intrauterine environment of diverse histotrophs, including nutrients, growth factors, cytokines, and chemokines. Here, we determined the functional role and signal transduction of CC-motif chemokine 20 (CCL20) in the porcine endometrium during pregnancy. The expression of CCL20 and its receptor CCR6 was abundant in the glandular epithelium (GE) and luminal epithelium (LE) of the porcine endometrium during early pregnancy. Administration of CCL20 to porcine endometrial LE cells increased cellular proliferation with strong PCNA expression by activation of PI3K and MAPK signaling. Blocking PI3K and MAPK decreased the CCL20-mediated elevated proliferation of pLE cells. Moreover, the proliferation of pLE cells was enhanced by inhibiting the LPS-induced cytokines and tunicamycin-induced endoplasmic reticulum (ER) stress response proteins. Overall, these results suggest that CCL20 may improve the endometrial receptivity through inducing proliferative signal transduction in the porcine endometrium during the early gestational period.