CCR8+ decidual regulatory T cells maintain maternal-fetal immune tolerance during early pregnancy

Regulatory T (Treg) cells play a vital role in maintaining maternal immune tolerance to the semiallogeneic fetus during pregnancy. Treg cell population heterogeneity and tissue-specific functions in the human decidua remain largely unknown. Here, using single-cell transcriptomic and T cell receptor sequencing of human CD4+ T cells from first-trimester deciduae and matched peripheral blood of pregnant women, we identified a highly activated, immunosuppressive CCR8+ Treg cell subset specifically enriched in the decidua (dTreg cells). CCR8+ dTreg cells were decreased in patients with recurrent pregnancy loss (RPL) and an abortion-prone mouse model. Depletion of CCR8+ dTreg cells increased susceptibility to fetal loss, with altered decidual immune profiles. Adoptive transfer of CCR8+ Treg cells rescued fetal loss in abortion-prone mice. The CCR8 ligand CCL1 was mainly produced by decidual CD49a+ natural killer cells and was significantly decreased in patients with RPL. Our data demonstrate that CCR8+ dTreg cells are required to maintain maternal-fetal tolerance and highlight potential avenues for RPL therapies.

Baicalein prevents pregnancy loss by maintaining regulatory T cell activation through inhibition of the TLR4/NF-κB signaling pathway

INTRODUCTION

Unexplained recurrent spontaneous abortion (URSA) involves multifactorial etiologies, with regulatory T cells (Tregs) playing a pivotal role in maintaining immune tolerance during pregnancy. Baicalein, a flavonoid from Scutellaria baicalensis, exhibits anti-inflammatory and immunomodulatory properties. This study evaluates baicalein's therapeutic potential in mitigating URSA via the TLR4/NF-κB signaling pathway.

METHODS

A URSA mouse model was used, and baicalein was administered intraperitoneally. Pregnancy outcomes, abortion rates, and placental morphology were assessed on gestational day 14 (G14). Treg cells were quantified via flow cytometry, and gene/protein expression levels were analyzed by immunohistochemistry, Western blotting, and real-time PCR. In vitro experiments on ihESCs further investigated the role of the TLR4/NF-κB pathway.

RESULTS

Baicalein reduced abortion rates from 33.3 % in URSA mice to 21.6 % (low dose) and 14.8 % (high dose), improved embryonic development by altering placental structure and decidual morphology, and reduced inflammation at the maternal-fetal interface. It expanded Treg cells and enhanced the expression of IGFBP-1 and PRL, markers of endometrial decidualization, and decreased TLR4, p-P65, and P65 expression. In vitro, baicalein's effects were abrogated by TLR4 inhibition, confirming pathway specificity.

DISCUSSION

Baicalein improved pregnancy outcomes by enhancing Treg function and promoting decidualization via TLR4/NF-κB pathway inhibition. These findings highlight baicalein's potential as a therapeutic agent for URSA.

Intradermal lymphocyte therapy: A promising treatment for recurrent pregnancy loss in patients without anti-TPO antibodies

BACKGROUND

Recurrent pregnancy loss (RPL) remains a complex and challenging reproductive issue often associated with immunological abnormalities. This study investigates the immunomodulatory effects of intradermal lymphocyte therapy in RPL patients, exploring cellular, molecular, and cytokine changes, with specific attention to individuals with positive anti-thyroid peroxidase antibodies (Anti-TPO).

METHODS

The study included 105 patients with RPL, divided into Anti-TPO positive RPL patients (n = 25), Anti-TPO negative RPL patients (n = 38), and RPL patients without lymphocyte immunotherapy (LIT) (n = 42). LIT was administered according to a standardized protocol, and various immune parameters including flow cytometry analysis of Th1/Th2, Th17, Treg, and NK cells, real-time PCR analysis of gene expression levels, and ELISA analysis of cytokine levels were assessed before and after LIT. Clinical outcomes including clinical miscarriage rates, delivery or pregnancy rates, and live birth rates were also evaluated.

RESULTS

Flow cytometry analysis revealed significant decreases in Th1/Th2 and NK cell percentages post-LIT in both Anti-TPO positive and negative RPL patients. Real-time PCR analysis showed significant alterations in gene expression levels of FoxP3, T-bet, GATA3, RORγt, IL-17, TGF-β, IFNγ, and IL-4 post-LIT in both groups. ELISA analysis demonstrated significant changes in levels of IL-17, TGF-β, IFNγ, and IL-4 post-LIT in both groups. Anti-TPO negative RPL patients with LIT had a lower miscarriage rate (10.53 %) compared to Anti-TPO positive RPL patients with LIT (40 %). Also, the pregnancy rate and the live birth rate were higher (89.47 %) in Anti-TPO negative RPL patients with LIT compared to Anti-TPO positive RPL patients with LIT (60 % and 56 % respectively). Moreover, the average pregnancy rate and live birth rate were significantly higher in RPL patients with LIT than in those without LIT (30.95 %).

CONCLUSION

These findings suggest that while LIT may confer benefits in improving pregnancy outcomes, its efficacy may be influenced by the presence of Anti-TPO Abs. These findings highlight the complex interplay between immune dysregulation and pregnancy outcomes in RPL patients and underscore the need for personalized treatment approaches.

Decoding immune tolerance in infertility: Exploring immune pathways and non-coding RNAs as pioneering biomarkers and therapeutic targets

Infertility, impacting a significant number of couples, is characterized by the failure to conceive after one year of consistent, unprotected sexual intercourse. It is multifactorial, with etiological contributors including ovulatory dysfunction, male reproductive anomalies, and tubal patency issues. Approximately 15% of infertility cases are classified as "unexplained," highlighting the complexity of this condition. Lifestyle determinants such as obesity and smoking further complicate reproductive outcomes, while infertility can also indicate underlying chronic health conditions. A specialized category, immune infertility, arises from a breakdown of immunological tolerance, an essential aspect for conception and the maintenance of pregnancy. The role of various immunological components, including immune cells, cytokines, chemokines, factors like HLA-G, etc., is pivotal in this context. Moreover, non-coding RNAs (ncRNAs) have emerged as critical regulators of immune tolerance within the reproductive axis. This review synthesizes the complex immunological pathways vital for successful implantation and the early stages of pregnancy alongside the regulatory roles of ncRNAs in these processes. Offering an integrated view of molecular and immunological interactions associated with infertility seeks to enhance our understanding of potential strategies to facilitate successful conception and sustain early pregnancy.

Molecular and cellular morphology of placenta unveils new mechanisms of reproductive immunology

INTRODUCTION

Despite of numerous studies of the placenta, some molecular and cellular characteristics, particularly the relationship among different cell types, have not been well understood. We aim to investigate the basic and intricate details of cellular and molecular elements in early and late phase placentas to gain better understanding of the immune regulation of human reproductive process.

METHODS

A novel combination of techniques of spatial transcriptomics(ST), multiple immunohistochemistry, and a dual labeling combining immunohistochemistry and (fluorescence in situ hybridization) FISH on normal and ectopic pregnancy and animal models was employed to investigate the placenta at tissue, cell, protein and molecular levels and to trace the fetal and maternal origin of every cell in early and late placentas.

RESULTS

Original discoveries include early expression of immune checkpoint proteins in embryo trophoblasts even before implantation. The detailed distributional relationships among different cell types of fetal and maternal origins in placenta and decidua indicate an immune rejection of the mother towards the fetus and this was counterbalanced by immune inhibitory proteins and blocking antibody Immunoglobulin G4 (IgG4) at the junction between the fetus and the mother. In contrary to common believe, we found that vascular endothelial and glandular epithelial cells in the decidua remain maternal in origin and were not replaced by fetal cells. At term placenta, fetal immune cells infiltrated into the maternal side of the decidus and vice versa indicating a possible immune reaction between fetal and maternal immune systems and suggesting a possible immune mechanism for trigger of parturition. The ability of trophoblasts to create an immune suppressed environment was also supported by findings in ectopic pregnancy and the animal models.

CONCLUSION

The findings indicate a fetus-driven mechanism of immune balance involving both cellular and humoral immunity in human reproduction.

Clinical Characteristics During and After COVID-19 Infection Among Healthcare Workers During the First Wave of Omicron in Chongqing, China

BACKGROUND

Revealing the clinical manifestations and associations of COVID-19 before and after negative transition remains an area of significant uncertainty. The aim of this study is to investigate the clinical characteristics observed during and after Omicron infection among a specific population, namely healthcare workers (HCWs).

METHODS

From November 4, 2022, to January 15, 2023, HCWs in our hospital were enrolled to document clinical symptoms, prevention, and treatment for COVID-19 using a structured questionnaire.

RESULTS

A total of 1101 HCWs were included, with SARS-CoV-2 infection detected in 78.20% (861/1101) during the observation period. The median duration for nucleic acid conversion was 8 days. Forty-three symptoms were identified during SARS-CoV-2 infection (11 symptoms per individual). The common symptoms were fever, cough, headache, phlegm production, and fatigue (60.67%-83.29%). These symptoms can be further categorized into five groups: fever type, upper respiratory tract type, influenza type, digestive system type, and systemic type-all showing complex and diverse patterns. Following SARS-CoV-2 infection, a total of 19 symptoms were recorded including four newly emerged ones: reduced lung capacity, memory loss, lethargy, and inattention. Importantly, we observed a significant association between gastrointestinal symptoms during the nucleic acid positive phase and subsequent neuropsychiatric manifestations after negative conversion. Interestingly, females experiencing menstruation or pregnancy exhibited a higher risk of infection, while inhaled vaccines and thymosin demonstrated a protective effect against SARS-CoV-2 infection.

CONCLUSIONS

The clinical manifestations observed in HCWs during and after Omicron infection displayed intricate patterns, shedding new light on the complex interplay between SARS-CoV-2 and humans.

Effects of the Zishen Yutai Pill on live births compared with placebo among infertile women with frozen-thawed embryo transfer cycle: A multicentre double-blind randomized controlled trial

BACKGROUND

Zishen Yutai Pill exhibited clinical benefit to infertile women undergoing fresh embryo transfer cycles, improving their pregnancy outcomes. However, as the endometrial environment in frozen embryo transfer (FET) is different from fresh cycles, the effects of ZYP on fresh embryo transfer could not be generalized to FET.

OBJECTIVE

We aimed to explore the effects of ZYP on live birth rate in women's FET cycles.

METHODS

This multicentre, double-blind, placebo-controlled, randomized study was conducted at 11 reproductive medical centres in China. Women were recruited and randomly assigned to ZYP or placebo intervention (5 g once, 3 times per day) around the time of FET. The live birth rate was set as the primary outcome. Secondary outcomes included implantation rate, biochemical pregnancy rate, clinical pregnancy rate, pregnancy loss rates. Data was analyzed based on the intention-to-treat principle, with per protocol analysis as sensitivity analysis.

RESULTS

Between December 2017 and April 2019, 934 women were screened, of whom 880 met all eligibility criteria and were allocated to ZYP (n=441) or placebo (n=439). In ITT analysis, the live birth rates were 38.32% (169/441) in ZYP group and 32.57% (143/439) (absolute difference 5.75%, 95%CI [-0.57%, 12.00%], OR 1.29, 95%CI [0.98, 1.70], P=0.08). The intervention of ZYP did not result in significantly differences in all secondary outcomes compared with placebo (all P>0.05). Similar trends were observed in PP analysis. In post hoc analysis, ZYP resulted in higher rates of live birth than placebo among women in specific subgroups, i.e., with miscarriage history (39.23% vs. 26.45%, P=0.01) or advanced maternal age (33.93% vs. 21.85%, P=0.04).

CONCLUSION

In infertile women undergoing FET cycle, intervention with ZYP led to a trend of live birth rate increment compared with placebo, but without statistical significance. However, women with miscarriage history and advanced age could experience possible benefits from ZYP intervention.

REGISTRATION

ChiCTR-INR-17010809 (http://www.chictr.org.cn).

Fetal ezrin expression affects macrophages and regulatory T cells in mouse placental decidua

Ezrin is a cross-linker protein between membrane proteins and cytosolic actin, abundantly expressed in the placenta among the ERM protein family. Ezrin gene knockout mice exhibit fetal growth restriction after gestational day (GD) 15.5. This study aimed to clarify the effect of ezrin on immune cells that influence fetal growth and immune tolerance. Ezrin heterozygous knockout (Ez+/-) mice were interbred, and the gene expressions and immune cell distributions in the placentas of wild-type (Ez+/+) and ezrin knockout (Ez-/-) fetuses were analyzed. IL-6 expression in the placenta of Ez-/- fetuses was significantly higher than in Ez+/+ fetuses at GD 15.5. The mRNA expression of IL-6 in the uterine decidua attached to Ez-/- fetuses was higher compared to that attached to Ez+/+ fetuses but not in the junctional zone and labyrinth. Classical M1 and M2 macrophages in the decidua were analyzed by flow cytometry using CD86 and CD206 as markers. M1 macrophages increased in the decidua attached to Ez-/- mice compared to Ez+/+ mice, while M2 macrophages did not increase. CD4-positive T cells showed a reduction in the decidua attached to Ez-/- fetuses. Further analysis involved the subcutaneous administration of tacrolimus in pregnant Ez+/- mice from GD 8.5 to GD 15.5, which prevented the decrease in fetal body weight and decidual CD4-positive T cells in Ez-/- mice at GD 15.5. These results suggest that impaired expression of fetoplacental-derived ezrin induces inflammatory conditions in the uterine decidua through M1 polarization of macrophages, increased IL-6, and decreased CD4-positive T cells, including Treg cells.

Association between Preconception Dietary Fiber Intake and Preterm Birth: The Japan Environment and Children's Study

Preterm birth (PTB) is a leading cause of neonatal morbidity and mortality. Therefore, this study aimed to determine whether preconception dietary fiber intake is associated with PTB. This was a prospective cohort Japan Environmental and Children's Study (JECS). The study population comprised 85,116 singleton live-birth pregnancies from the JECS database delivered between 2011 and 2014. The participants were categorized into five groups based on their preconception dietary fiber intake quintiles (Q1 and Q5 were the lowest and highest groups, respectively). Multiple logistic regression analysis was performed to determine the association between preconception dietary fiber intake and PTB. Multiple logistic regression analysis revealed that the risk for PTB before 34 weeks was lower in the Q3, Q4, and Q5 groups than in the Q1 group (Q3: adjusted odds ratio [aOR] 0.78, 95% confidence interval [CI] 0.62-0.997; Q4: aOR 0.74, 95% CI 0.57-0.95; Q5: aOR 0.68, 95% CI 0.50-0.92). However, there was no significant difference between preconception dietary fiber intake and PTB before 37 weeks. In conclusion, higher preconception dietary fiber intake correlated with a reduced the risk for PTB before 34 weeks. Therefore, new recommendations on dietary fiber intake as part of preconception care should be considered.

Classification of preeclampsia according to molecular clusters with the goal of achieving personalized prevention

The prevention of pre-eclampsia is difficult due to the syndromic nature and multiple underlying mechanisms of this severe complication of pregnancy. The current clinical distinction between early- and late-onset disease, although clinically useful, does not reflect the true nature and complexity of the pathologic processes leading to pre-eclampsia. The current gaps in knowledge on the heterogeneous molecular pathways of this syndrome and the lack of adequate, specific diagnostic methods are major obstacles to early screening and tailored preventive strategies. The development of novel diagnostic tools for detecting the activation of the identified disease pathways would enable early, accurate screening and personalized preventive therapies. We implemented a holistic approach that includes the utilization of different proteomic profiling methods of maternal plasma samples collected from various ethnic populations and the application of systems biology analysis to plasma proteomic, maternal demographic, clinical characteristic, and placental histopathologic data. This approach enabled the identification of four molecular subclasses of pre-eclampsia in which distinct and shared disease mechanisms are activated. The current review summarizes the results and conclusions from these studies and the research and clinical implications of our findings.

Impact of Aging and Cellular Senescence in the Pathophysiology of Preeclampsia

The incidence of hypertensive disorders of pregnancy is increasing, which may be due to several factors, including an increased age at pregnancy and more comorbid health conditions during reproductive years. Preeclampsia, the most severe hypertensive disorder of pregnancy, has been associated with an increased risk of future disease, including cardiovascular and kidney diseases. Cellular senescence, the process of cell cycle arrest in response to many physiologic and maladaptive stimuli, may play an important role in the pathogenesis of preeclampsia and provide a mechanistic link to future disease. In this article, we will discuss the pathophysiology of preeclampsia, the many mechanisms of cellular senescence, evidence for the involvement of senescence in the development of preeclampsia, as well as evidence that cellular senescence may link preeclampsia to the risk of future disease. Lastly, we will explore how a better understanding of the role of cellular senescence in preeclampsia may lead to therapeutic trials. © 2023 American Physiological Society. Compr Physiol 13:5077-5114, 2023.

Tryptophan metabolism and immune alterations in pregnant Hispanic women with chronic Toxoplasma gondii infection

PROBLEM

Pregnancy markedly modifies women's metabolism and immune functions. We hypothesized that pregnancy might alter the immune and metabolic responses to chronic Toxoplasma gondii infection in pregnancy.

METHOD OF STUDY

A population of 690 pregnant Hispanic women were screened for antibodies to T. gondii and 158 women were positive (23% positivity) with 83% showing high avidity indices. These seropositive women were followed through their pregnancies with four data collection time points and a postpartum collection at two clinics in Tampa, Florida. A T. gondii seronegative group (N = 128) was randomly selected to serve as a control group and measured along pregnancy in the same way. Serum levels of tryptophan, kynurenine, and their ratio, phenylalanine, tyrosine and their ratio, neopterin, and nitrite were measured through pregnancy and the postpartum. A plasma cytokine panel (IFN-γ, TNFα, IL-2, IL-10, IL-12, IL-6, IL-17) was analyzed in parallel.

RESULTS

The major findings suggest that indoleamine 2,3-dioxygenase (IDO-1) was less activated in T. gondii seropositive pregnant Hispanic women with chronic infection. Evidence for IDO-1 suppression was that tryptophan catabolism was less pronounced and there were lower levels of multiple inflammatory cytokines including IFN-γ, which is the major inducer of IDO-1, and higher nitrite concentration, a surrogate marker for nitric oxide, an inhibitor of IDO.

CONCLUSIONS

Latent T. gondii infection was associated with higher plasma tryptophan levels, and lower inflammatory cytokines across pregnancy, suggesting suppression of the IDO-1 enzyme, and possible T cell exhaustion during pregnancy.

Phenotypes of peripheral CD4+ T helper cell subsets in pregnant women with HBeAg-negative chronic asymptomatic HBV carriers

Background

Chronic hepatitis B virus (HBV) infection is a major public health problem worldwide, and mother-to-child transmission is the key mode of HBV infection. CD4⁺ T helper (Th) cells play a critical role in the immune microenvironment of specific maternal tolerance to the foetus during pregnancy. However, the roles of Th cell subsets in pregnant women (PW) with chronic asymptomatic HBV carriers (ASCs) remain completely unclear. Here, we aimed to characterize CD4⁺ T-cell immunity in PW with hepatitis Be antigen (HBeAg)-negative chronic ASCs.

Methods

Human peripheral blood mononuclear cells (PBMCs) from PW without HBV infection or with chronic ASCs and healthy controls (HC) were isolated, and CD4⁺ Th cell subsets were detected by flow cytometry in addition to serum cytokines. Serological HBV markers, liver function and hormone levels of these individuals were also tested.

Results

The frequencies of circulating T follicular helper (Tfh) type 2 (Tfh2) cells were significantly evaluated, but Tfh1 cell frequencies were notably decreased in PW compared to HC. Moreover, the frequencies of Th22 cells were only notably increased in PW with chronic ASCs in comparison with PW. Additionally, increased levels of serum IL-4 were positively correlated with Tfh2 cell frequencies in healthy PW. Interestingly, serum P4 levels were positively associated with the frequencies of circulating Tfh2 or Th2 cells but were negatively related to the frequencies of circulating Tfh17 or Th17 cells in healthy PW. Although there were some changes in the other CD4⁺ Th cell frequencies and cytokine levels or other references, significant differences were not found among HC, healthy PW, PW with HBeAg-negative chronic ASCs.

Conclusion

CD4⁺ Th cell subsets played a critical role in the immune microenvironment of PW, and these findings provided potential evidence for why PW with chronic ASCs did not receive antenatal antiviral prophylaxis.