IL-10-producing B cells play important role in the pathogenesis of recurrent pregnancy loss

Immunologic insights in recurrent spontaneous abortion: Molecular mechanisms and therapeutic interventions

Recurrent spontaneous abortion refers to the occurrence of two or more spontaneous abortions before or during the early stages of pregnancy. The immune system plays a crucial role in the maintenance of pregnancy and embryo implantation. Various immune cells, cytokines, and immune regulatory pathways are involved in the complex immune balance required for a stable pregnancy. Studies suggest that immune abnormalities may be associated with some recurrent spontaneous abortion cases, particularly those involving the dysregulation of immune cell function, autoimmune responses, and placental immunity. In terms of treatment, interventions targeting immune mechanisms are crucial. Various therapeutic approaches, including immunomodulatory drugs, immunoadsorption therapies, and immunocellular therapies, are continually being researched and developed. These approaches aim to restore the immune balance, enhance the success rate of pregnancies, and provide more effective treatment options for patients with recurrent spontaneous abortion.

Immunological Indicators of Recurrent Pregnancy Loss: A Mendelian Randomization Study

Recurrent pregnancy loss (RPL) is thought to be related to maternal-fetal immune tolerance disorders. Immune monitoring of RPL patients mainly involves two aspects: inflammatory factors and immune cells. However, most observational studies have reported controversial findings. This study aimed to confirm whether abnormal inflammatory factors and immune cells in peripheral blood may lead to RPL, and guide clinical immune monitoring. We demonstrated causality using two-sample Mendelian randomization. Sensitivity analysis, reverse Mendelian randomization and meta-analysis were used to enhance the effectiveness of the results. There was a causal relationship between the level of IL-12 (OR = 1.78, 95% CI = 1.25-2.55; P = 0.00149) and RPL for 41 inflammatory factors. We screened 5 groups of immune cell subtypes that were causally associated with RPL: switched memory B-cell absolute count (OR = 0.66, 95% CI = 0.49-0.87, P = 0.00406), IgD + CD24 + B-cell absolute count (OR = 0.69, 95% CI = 0.53-0.88, P = 0.00319), CD39 + resting CD4 regulatory T-cell %CD4 regulatory T-cell (OR = 0.86, 95% CI = 0.78-0.95, P = 0.00252), activated & resting CD4 regulatory T-cell %CD4 regulatory T-cell (OR = 0.89, 95% CI = 0.82-0.97, P = 0.00938) and CD45 RA + CD28-CD8 + T-cell %CD8 + T-cell (OR = 0.99, 95% CI = 0.98-1.00, P = 0.01231). In terms of inflammatory factors, a causal relationship between IL-12 and RPL in peripheral blood was confirmed. We also identified five immune cell phenotypes that play a protective role. This suggests that there may be protective B cells and CD8 + T-cell subsets in peripheral blood, and the protective effect of Tregs was proved again. Immune monitoring of peripheral blood in patients with RPL seems to be necessary and the foundation for precision medicine.

The association of Treg and Th17 cells development factors and anti-TPO autoantibodies in patients with recurrent pregnancy loss

OBJECTIVES

Thyroid autoimmunity is considered as the most prevalent autoimmune condition in women in fertility age. There are different clinical evidences indicating the association between thyroid autoimmunity and increased risk of RPL. This study aimed to analyze the association of Tregs and Th17 cells development factors and anti-thyroid peroxidase (anti-TPO) antibodies in RPL patients. Healthy controls (n = 36), TPO + controls (n = 25) and TPO + RPL (n = 32) participated in this study. After blood sampling, the frequency of Th17 and Tregs was evaluated using flow cytometry. Real-time PCR and ELISA was used to assess the status of Tregs and Th17 related transcription factors and cytokines in mRNA and protein level, respectively.

RESULTS

TPO + RPL group showed a higher Th17 frequency compared to healthy controls and TPO + controls groups (p = 0.0002 and p = 0.04, respectively). Additionally, mRNA expression levels of RORγT and IL-17 were significantly higher in TPO + RPL compared to healthy controls and TPO + controls groups. In contrast, Foxp3 and TGFβ expression was lower in TPO + RPL. ELISA findings also indicated a significantly higher IL-17 and lower TGFβ secretion in TPO + RPL compared to healthy controls and TPO + controls. Thyroid autoimmunity should intensely be controlled specially in patients with RPL history.

Lupus and recurrent pregnancy loss: the role of female sex hormones and B cells

Systemic lupus erythematosus is a debilitating autoimmune disease characterized by uncontrolled activation of adaptive immunity, particularly B cells, which predominantly affects women in a 9 to 1 ratio compared to men. This stark sex disparity strongly suggests a role for female sex hormones in the disease's onset and progression. Indeed, it is widely recognized that estradiol not only enhances the survival of autoreactive B cells but also stimulates the production of autoantibodies associated with systemic lupus erythematosus, such as anti-nuclear antibodies and anti-dsDNA antibodies. Clinical manifestations of systemic lupus erythematosus typically emerge after puberty and persist throughout reproductive life. Furthermore, symptoms often exacerbate during the premenstrual period and pregnancy, as increased levels of estradiol can contribute to disease flares. Despite being fertile, women with lupus face a heightened risk of pregnancy-related complications, including pregnancy loss and stillbirth, which significantly surpass the rates observed in the healthy population. Therefore, this review aims to summarize and discuss the existing literature on the influence of female sex hormones on B-cell activation in patients with systemic lupus erythematosus, with a particular emphasis on their impact on pregnancy loss.

The effect of lymphocyte immunotherapy (LIT) in modulating immune responses in patients with recurrent pregnancy loss (RPL)

In order to prevent miscarriage in RPL patients, the goal of this study was to determine how well lymphocyte immunotherapy (LIT) works in modifying immunological responses produced by cells, cytokines, transcription factors, and microRNAs. 200 RPL patients and 200 healthy controls were included in the study. Using flow cytometry, it was possible to compare the frequency of cells before and after lymphocyte treatment. Real-time PCR was used to assess the gene expression levels of transcription factors, cytokines, and microRNAs. ELISA method was used to evaluate the level of secretion of cytokines in the serum. Primary evaluation of the immune profile between healthy controls and RPL cases showed a higher frequency of Th17, NK, B cells and a lower frequency of Treg cells in RPL cases. Also, pro-inflammatory cytokines showed increased expression at mRNA and protein levels in the RPL group in comparison with the control group. Whereas, anti-inflammatory cytokines showed decreased expression in RPL patients. Decreased and increased frequency of Th17 and Treg lymphocytes observed in RPL cases following LIT, respectively. The same results obtained for RORγt and FoxP3 mRNA expression as transcription factor of Th17 and Treg cells, respectively. NK cell cytotoxicity decreased after LIT in RPL patients. miR-326a and miR-155 expression after LIT reduced, but miR-146a and miR-10a expression increased in RPL instances. LIT in RPL cases causes to elevation and modulation of anti-inflammatory and pro-inflammatory cytokines. Our data showed that lymphocyte therapy can be proposed as an effective therapeutic agent in RPL patients with immunological background by a modulating inflammatory condition.

The evaluation of CD39, CD73, and HIF-1 α expression besides their related miRNAs in PBMCs of women with recurrent pregnancy loss

The molecular mechanisms involved in the pathogenesis of recurrent pregnancy loss (RPL) are not completely recognized. The present study aimed to assess the molecules associated with ATP catabolism and hypoxia besides their related miRNAs in patients with RPL. The frequency of Th17 and Treg cells in PBMCs of RPL women and healthy pregnant women were evaluated with Flow cytometry. The expression levels of CD39, CD73, and Hypoxia-inducible factor-alpha (HIF-1α), miR-18a, miR-30a, and miR-206 in PBMCs of two groups were measured with real-time PCR and western blotting. Then, serum levels of IGF-1, TGF-β, and HIF-1α were measured by ELISA. Our results indicated a higher (p = 0.0002) and lower (p < 0.0001) frequency of Th17 and Treg lymphocytes in RPL women, respectively. The expression level of CD39 decreased in PBMCs of RPL women whereas the level of CD73 and HIF-α increased (p = 0.0010, 0.0023, 0.0006 respectively). The results of CD39 and CD37 were also confirmed by protein analysis (p = 0.0047, 0.0364 respectively). Almost, the same results for CD39 and CD73 expression at mRNA and protein levels were observed in isolated Treg cells. Moreover, we found the higher expression of miR-206 and miRNA-30a (p = 0.0038, 0.0123), but the lower expression of miRNA-18a (p = 0.0101) in RPL. The concentration level of IGF-1, and TGF-β reduced (p = 0.0017, 0.0065 respectively) while the level of HIF-α elevated (p = 0.0235) in serum samples of RPL. In conclusion, we observed the dysregulation of molecules that are involved in ATP catabolism and hypoxia, including CD39, CD73, and HIF-1a which is related to miR-18a, miR-30a, and miR-206 change in RPL women. It may be potentially used for RPL prognosis by more comprehensive future studies.

The immunomodulatory effect of intradermal allogeneic PBMC therapy in patients with recurrent spontaneous abortion

BACKGROUND

There has been limited study on the impact of PBMC therapy in RSA patients with immunological disorders such as Th17 and Treg cell dysregulation, as well as their associated factors. This study aimed to assess the efficacy of PBMC therapy in modulating immune cell frequency, cytokine production, transcription factors, and miRNAs implicated in the regulation of their function, as well as their potential superiority to routine treatments.

METHODS

Fifty RSA women who had received PBMCs and 50 matched-paired control RSA women who had received the routine treatments were recruited and followed for three months. The frequencies of Th17, Treg, NK, and B cells were assessed using flow cytometry. Thereafter, the gene expression level of the transcription factors and related miRNAs of Treg cell and Th17 cell was quantified using RT-PCR. Then ELISA was employed to assess the cytokine production of Th17 and Treg cells. Finally, the live birth rate and miscarriage rate were evaluated as clinical outcomes in this study.

RESULTS

Flow cytometry analysis revealed that PBMC therapy significantly reduces the frequencies of Th17 and NK cells while enhancing the frequency of Treg cells. RT-PCR analysis confirmed that PBMC therapy significantly downregulates RORγt and upregulates FoxP3. Likewise, RT-PCR analysis showed that PBMC therapy reduces the expression of miR-25, miR-155, and miR-326 while increasing the expression of miR-10a. ELISA results demonstrated that PBMC therapy considerably decreases the concentration of inflammatory cytokines IL-1β, IL-17, and TNF-α and enhances the concentration of anti-inflammatory cytokines IL-10 and TGF-β. Following PBMC therapy live birth rate raised while miscarriage rate reduced.

CONCLUSION

Our findings suggested that, in contrast to routine treatments, PBMC therapy can significantly modulate the maternal immune system by enhancing the Treg/Th17 paradigm and regulating the expression of Treg and Th17 cell-associated cytokines, transcription factors, and miRNAs. This treatment also can increase the live birth rate in RSA patients.

Insights into the immunomodulatory regulation of matrix metalloproteinase at the maternal-fetal interface during early pregnancy and pregnancy-related diseases

Trophoblast immune cell interactions are central events in the immune microenvironment at the maternal-fetal interface. Their abnormalities are potential causes of various pregnancy complications, including pre-eclampsia and recurrent spontaneous abortion. Matrix metalloproteinase (MMP) is highly homologous, zinc(II)-containing metalloproteinase involved in altered uterine hemodynamics, closely associated with uterine vascular remodeling. However, the interactions between MMP and the immune microenvironment remain unclear. Here we discuss the key roles and potential interplay of MMP with the immune microenvironment in the embryo implantation process and pregnancy-related diseases, which may contribute to understanding the establishment and maintenance of normal pregnancy and providing new therapeutic strategies. Recent studies have shown that several tissue inhibitors of metalloproteinases (TIMPs) effectively prevent invasive vascular disease by modulating the activity of MMP. We summarize the main findings of these studies and suggest the possibility of TIMPs as emerging biomarkers and potential therapeutic targets for a range of complications induced by abnormalities in the immune microenvironment at the maternal-fetal interface. MMP and TIMPs are promising targets for developing new immunotherapies to treat pregnancy-related diseases caused by immune imbalance.

Sirolimus- and cyclosporine-loaded nanostructured lipid carriers: Development, characterization, and in vitro evaluation in T-cell profiles of patients with a history of recurrent pregnancy loss

Purpose

The authors developed nanostructured lipid carriers (NLCs) loaded with sirolimus (SRL) and cyclosporine (CsA) to improve their therapeutic efficacy in recurrent pregnancy loss (RPL) patients.

Methods

Mono-delivery and co-delivery of SRL and CsA by NLCs (S-NLCs, C-NLCs, and S-C-NLCs) were developed. The MTT assay was used to study the optimum dose of formulations. PCR, Western blotting, and ELISA were also conducted.

Results

Well-designed nanodrugs with a suitable size, zeta potential, desirable encapsulation efficiency drug loading, and cellular uptake confirmed optimum formulations. Based on cell viability, the amounts of SRL and CsA could be reduced greatly due to the co-delivery by NLCs. Following S-NLCs and C-NLCs interventions in T cells of patients with RPL and immune abnormality, a significant difference was observed in transcription factors and cytokine levels of Th1, Th17, and Tregs compared with healthy samples. Thus, a higher level of pro-inflammatory cytokines (IFN-γ, TNF-α, IL-17, and IL-21) and their regulators (T-bet and RORγt), as well as a lower level of an anti-inflammatory cytokine (IL-10) and its regulatory (Foxp3), were observed. However, no significant difference was found following the S-C-NLCs intervention.

Conclusions

S-C-NLCs effectively balance the immune responses in peripheral T cells in RPL patients to induce maternal immune tolerance.

The Progress of Research on Genetic Factors of Recurrent Pregnancy Loss

Recurrent pregnancy loss (RPL) is both mental and physical health problem affecting about 1-5% of women of childbearing age. The etiology of RPL is complex, involving chromosomal abnormalities, autoimmune diseases, metabolic disorders, and endometrial dysfunction. The causes of abortion are still unknown in more than 50% of these cases. With the development of science and technology, an increasing number of scholars focus on this field and find that genetic factors may play an essential role in unexplained RPL, such as embolism-related genes, immune factor-related genes, and chromosomal numeric, and structural variation. This review summarizes the genetic factors associated with RPL, including genetic mutations and genetic polymorphisms, chromosomal variants, and chromosomal polymorphisms. Many related genetic factors have been found to be demographically and geographically relevant, some of which can be used for risk prediction or screening for the etiology of RPL. However, it is difficult to predict and prevent RPL due to uncertain pathogenesis and highly variable clinical presentation. Therefore, the genetic factors of RPL still need plentiful research to obtain a more accurate understanding of its pathogenesis and to provide more detection means for the screening and prevention of RPL.

Relationship between the Dietary Inflammatory Index Score and Cytokine Levels in Chinese Pregnant Women during the Second and Third Trimesters

The impact of dietary inflammatory potential on serum cytokine concentrations in second and third trimesters of Chinese pregnant women is not clear. A total of 175 pregnant women from the Tianjin Maternal and Child Health Education and Service Cohort (TMCHESC) were included. The dietary inflammatory index (DII) was calculated based on 24-h food records. Serum tumor necrosis factor-α (TNF-α), interleukin 1β (IL-1β), IL-6, IL-8, IL-10, C-reactive protein (CRP), and monocyte chemoattractant protein-1 (MCP-1) levels in the second and third trimesters were measured. The mean DII scores (mean ± SD) were -0.07 ± 1.65 and 0.06 ± 1.65 in the second and third trimesters, respectively. In the third trimester, IL-1β (p = 0.039) and MCP-1 (p = 0.035) levels decreased and then increased with increasing DII scores. IL-10 concentrations decreased in pregnant women whose DII scores increased between the second and third trimesters (p = 0.011). Thiamin and vitamin C were negatively correlated with MCP-1 (β = -0.879, and β = -0.003) and IL-6 (β = -0.602, and β = -0.002) levels in the third trimester. In conclusion, the DII score had a U-shaped association with cytokine levels during the third trimester. Changes in DII scores between the second and third trimesters of pregnancy were correlated with cytokine levels during the third trimester.

A Comprehensive Investigation into the Distribution of Circulating B Cell Subsets in the Third Trimester of Pregnancy

Maternal B cells play a crucial role in the development and maintenance of pregnancy, due to their humoral activities and regulatory functions. In the study, we investigated the alterations in the distributions of naïve and memory B cell subsets, as well as regulatory B (Breg) cells, in the third trimester of pregnancy. Peripheral blood from 14 healthy pregnant women in the third trimester and 7 healthy non-pregnant women was collected and examined for the frequencies of B cell subsets, including IgD⁺CD27⁻ naïve, IgD⁺CD27⁺ un-switched memory, IgD⁻CD27⁺ switched memory, CD38^intCD24^int mature–naïve, CD38⁻CD24^hi primarily memory and CD38^hiCD24^hi transitional B cells by flow cytometry. Breg cell subsets were also characterized based on the expression of CD5, CD1d and IL-10. In pregnant women, the proportions of un-switched memory and transitional B cells were significantly decreased. Additionally, the frequencies of both CD5⁺CD1d⁺ Breg and IL-10-producing B10 cells were decreased in pregnancy. Changes in the distribution of transitional B cells as well as Breg cells may be crucial contributors for the development of altered maternal immune responses and tolerance needed for the maintenance of normal pregnancy in the third trimester.

Allogeneic lymphocytes immunotherapy in female infertility: Lessons learned and the road ahead

The endometrium is an essential tissue in the normal immunologic dialogue between the mother and the conceptus, which is necessary for the proper establishment and maintenance of a successful pregnancy. It's become evident that the maternal immune system plays a key role in the normal pregnancy's initiation, maintenance, and termination. In this perspective, the immune system contributes to regulating all stages of pregnancy, thus immunological dysregulation is thought to be one of the major etiologies of implantation failures. Many researchers believe that immune therapies are useful tactics for improving the live births rate in certain situations. Lymphocyte immunotherapy (LIT) is an active form of immunotherapy that, when used on the relevant subgroups of patients, has been shown in multiple trials to dramatically enhance maternal immunological balance and pregnancy outcome. The primary goal of LIT is to regulate the immune system in order to create a favorable tolerogenic immune milieu and tolerance for embryo implantation. However, there are a plethora of influential factors influencing its therapeutic benefits that merit to be addressed. The objective of our study is to discuss the mechanisms and challenges of allogeneic LIT.

The role of endometrial B cells in normal endometrium and benign female reproductive pathologies: a systematic review

STUDY QUESTION

What are the similarities and differences in endometrial B cells in the normal human endometrium and benign reproductive pathologies?

SUMMARY ANSWER

Endometrial B cells typically constitute <5% of total endometrial CD45⁺ lymphocytes, and no more than 2% of total cells in the normal endometrium, and while their relative abundance and phenotypes vary in benign gynaecological conditions, current evidence is inconsistent.

WHAT IS KNOWN ALREADY

B cells are vitally important in the mucosal immune environment and have been extensively characterized in secondary lymphoid organs and tertiary lymphoid structures (TLSs), with the associated microenvironment germinal centre. However, in the endometrium, B cells are largely overlooked, despite the crucial link between autoimmunity and reproductive pathologies and the fact that B cells are present in normal endometrium and benign female reproductive pathologies, scattered or in the form of lymphoid aggregates (LAs). A comprehensive summary of current data investigating B cells will facilitate our understanding of endometrial B cells in the endometrial mucosal immune environment.

STUDY DESIGN, SIZE, DURATION

This systematic review retrieved relevant studies from four databases (MEDLINE, EMBASE, Web of Science Core Collection and CINAHL) from database inception until November 2021.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The search strategy combined the use of subject headings and relevant text words related to ‘endometrium’, ‘B cells’ and B-cell derivatives, such as ‘antibody’ and ‘immunoglobulin’. Non-benign diseases were excluded using cancer-related free-text terms, and searches were limited to the English language and human subjects. Only peer-reviewed research papers were included. Each paper was graded as ‘Good’, ‘Fair’ or ‘Poor’ quality based on the NEWCASTLE-OTTAWA quality assessment scale. Only ‘Good’ quality papers were included.

MAIN RESULTS AND THE ROLE OF CHANCE

Twenty-seven studies met the selection criteria and were included in this review: 10 cross-sectional studies investigated B cells in the normal endometrium; and 17 case–control studies compared the characteristics of endometrial B cells in control and benign female reproductive pathologies including endometritis, endometriosis, infertility, abnormal uterine bleeding, endometrial polyps and uterine fibroids. In all studies, B cells were present in the endometrium, scattered or in the form of LAs. CD20⁺ B cells were more abundant in patients with endometritis, but the data were inconsistent as to whether B-cell numbers were increased in endometriosis and patients with reproductive pathologies.

LIMITATIONS, REASONS FOR CAUTION

Although only ‘good’ quality papers were included in this systematic review, there were variations in patients’ age, diagnostic criteria for different diseases and sample collection time among included studies. Additionally, a large number of the included studies only used immunohistochemistry as the identification method for endometrial B cells, which may fail to provide an accurate representation of the numbers of endometrial B cells.

WIDER IMPLICATIONS OF THE FINDINGS

Histological studies found that endometrial B cells are either scattered or surrounded by T cells in LAs: the latter structure seems to be under hormonal control throughout the menstrual cycle and resembles TLSs that have been observed in other tissues. Further characterization of endometrial B cells and LAs could offer insights to endometrial B-cell function, particularly in the context of autoimmune-associated pathologies, such as endometriosis. Additionally, clinicians should be aware of the limited value of diagnosing plasma cell infiltration using only CD138.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by Finox Biotech. The authors have no conflicts of interest to declare.

PROSPERO REGISTRATION NUMBER

This systematic review was registered in PROSPERO in January 2020 (PROSPERO ID: CRD42020152915).

Role of CD20 + IL-10 + B-lymphocytes in immunoregulatory processes in women with reccurent miscarriage

To determine the level of CD20 + IL-10 + B-lymphocytes in pregnant women with the threat of termination of pregnancy at 5-12 weeks and recurrent miscarriage in history and compare the data obtained with the end of gestation. A survey of 65 women at a gestational age of 5-12 weeks was carried out. The main group consisted of 33 women with a threatening recurrent miscarriage at the time of the examination, the comparison group consisted of 10 pre-pregnant women with a threatening sporadic miscarriage at the time of the examination, the control group consisted of 22 pregnant women without signs of a threatening miscarriage. The main group, depending on the outcomes of pregnancy, is divided into 2 subgroups: subgroup A - pregnancy ended in undeveloped pregnancy or miscarriage (9 women), subgroup B - pregnancy ended in childbirth (24 women). The relative content of CD20 + IL-10 + B-lymphocytes was determined by flow cytometry on FACSCanto II (Becton Dickinson, USA). Women in the main group had a significantly lower level of CD20 + IL-10 + B-lymphocytes in comparison with the rest of the surveyed. A retrospective analysis revealed that among women of subgroup A there was a sharp decrease in CD20 + IL-10 + cells compared with subgroup B. Prediction of a non-developing pregnancy and spontaneous miscarriage up to 22 weeks of gestation in pregnant women with threatened spontaneous miscarriage and a history of recurrent miscarriage is possible with the relative content of CD20 + IL-10 + equal to or less than 4.5% (sensitivity 100%, specificity 82.6%, accuracy 87.9%).

Immune checkpoints and reproductive immunology: Pioneers in the future therapy of infertility related Disorders?

As co-stimulatory receptors, immune checkpoint molecules are found on the surface of various immune cells and transduce inhibitory signals following ligand binding. The most studied members in this regard include PD-1, TIM-3, and CTLA-4. The physiological part immune checkpoints possess is the prevention of dangerous immune attacks towards self-antigens throughout an immune response, which takes place through the negative regulation of the effector immune cells, through the induction of T-cell exhaustion, for instance. It has recently been suggested that each checkpoint reduces immunoactivation via distinct intracellular mechanisms of signaling. Regulators of immune checkpoints are supposed to participate actively in immune defense mechanisms against infections, preventing autoimmunity, transplantation, and tumor immune evasion. In pregnancy, as an active immunotolerance mechanism which is also natural, the maternal immune system encounters two simultaneous challenges; in addition to accepting the semi-allogeneic fetus, the maternal immune system should also prevent infections. In this regard, the part immune checkpoint molecules possess is particularly interesting. Herein, the current understanding of such part in reproductive immunology is described.

The promising biological role of postbiotics derived from probiotic Lactobacillus species in reproductive health

Recent investigations have meaningfully developed our knowledge of the features of the reproductive microbiome/metabolome profile and their relations with host responses to offer an optimal milieu for the development of the embryo during the peri-implantation period and throughout pregnancy. In this context, the establishment of homeostatic circumstances in the Female Reproductive Tract (FRT), in various physiological periods, is a significant challenge, which appears the application of postbiotics can facilitate the achievement of this goal. So, currently, scientific literature confirms that postbiotics due to their antimicrobial, antiviral, and immunomodulatory properties can be considered as a novel biotherapeutic approach. Future investigation in this field will shed more translational mechanistic understanding of the interaction of the postbiotics derived from vaginal Lactobacilli with females' health and reproduction.

T lymphocytes and preeclampsia: The potential role of T-cell subsets and related MicroRNAs in the pathogenesis of preeclampsia

Innate and adaptive immune systems have a crucial role in initiating and progressing some pregnancy disorders such as preeclampsia (PE), which is one of the pregnancy-specific disorders that could result in neonatal and maternal morbidity and mortality. The dysregulation of the spiral artery and inadequate trophoblast invasion lead to PE symptoms through producing various inflammatory cytokines and anti-angiogenic factors from the placenta. T lymphocytes play a special role in the epithelium and stroma of the human endometrium. CD4+ T helper (Th) cells, Th1/Th2, and Th17/T regulatory (Treg) balance mainly contribute to the establishment of a pregnancy-favorable environment. This review examined the dysregulation of some cytokines produced from T cells, the dysregulation of the transcription factors of Th cells, the expression of chemokine receptors on T cells, as well as the effects of some factors including vitamin D on the activity of T cells, and finally, the dysregulation of various miRNAs related to T cells, which could cause PE.

Immunosuppressive Mechanisms of Regulatory B Cells

Regulatory B cells (Bregs) is a term that encompasses all B cells that act to suppress immune responses. Bregs contribute to the maintenance of tolerance, limiting ongoing immune responses and reestablishing immune homeostasis. The important role of Bregs in restraining the pathology associated with exacerbated inflammatory responses in autoimmunity and graft rejection has been consistently demonstrated, while more recent studies have suggested a role for this population in other immune-related conditions, such as infections, allergy, cancer, and chronic metabolic diseases. Initial studies identified IL-10 as the hallmark of Breg function; nevertheless, the past decade has seen the discovery of other molecules utilized by human and murine B cells to regulate immune responses. This new arsenal includes other anti-inflammatory cytokines such IL-35 and TGF-β, as well as cell surface proteins like CD1d and PD-L1. In this review, we examine the main suppressive mechanisms employed by these novel Breg populations. We also discuss recent evidence that helps to unravel previously unknown aspects of the phenotype, development, activation, and function of IL-10-producing Bregs, incorporating an overview on those questions that remain obscure.

Intrauterine administration of peripheral blood mononuclear cells activated by human chorionic gonadotropin in patients with repeated implantation failure: A meta-analysis

The purpose of this study was to assess whether intrauterine administration of peripheral blood mononuclear cells (PBMCs) activated by human chorionic gonadotropin (hCG) could improve the pregnancy and live birth rates in women with repeated implantation failure (RIF), and whether the parameters of co-culture of hCG and PBMCs would affect the clinical outcomes. Six databases (PubMed, Ovid, Medline, NCBI, Cqvip and Wanfang) were searched up to October 2020 by two independent reviewers. Seven studies were included according to specific inclusion and exclusion criteria. A meta-analysis showed that the pregnancy and live birth rates were significantly increased in the case group compared with the control group (odds ratio [OR]: 3.43, 95 % confidence interval [CI]: 1.78-6.61; P =  0.0002 and OR: 2.79, 95 % CI: 1.09-7.15; P =  0.03), especially when hCG was cultured with PBMCs for 48 h or PBMCs administration was performed two or three days before embryo transfer (ET). Neither the dosage of the hCG co-cultured with PBMCs nor the mean concentration of the administered PBMCs appeared to influence the therapeutic efficiency. In conclusion, intrauterine administration of PBMCs co-cultured with hCG for 48 h, conducted two or three days before ET, could be an effective therapy for women experiencing RIF. Due to the limitations of sample size and quality of the included studies, further high-quality studies with large sample sizes are warranted to optimize the parameters of hCG and PBMC co-culture to help more RIF patients benefit from this therapy.

Fetomaternal Immune Tolerance: Crucial Mechanisms of Tolerance for Successful Pregnancy in Humans

For many years, the question of how the maternal immune system tolerates the foreign fetus has remained unanswered, and numerous studies have considerably attempted to elucidate underlying mechanisms for fetomaternal tolerance. This review aimed at discussing various significant mechanisms in fetomaternal compatibility. At the fetomaternal interface, in addition to having efficient control against infections, innate and adaptive maternal immune systems selectively prevent fetal rejection. In general, understanding the complex mechanisms of fetomaternal tolerance is critical for immunologic tolerance induction and spontaneous abortion prevention in high-risk populations. Different cells and molecules, such as regulatory T-cells, dendritic cells, decidua cells, IDO, Class I HLA molecules, TGF-β, and IL-10, induce maternal immune tolerance in the fetus in numerous ways. The findings on fetomaternal immune tolerance have remained controversial and require further research.

Altered Th17/Treg ratio as a possible mechanism in pathogenesis of idiopathic membranous nephropathy

Idiopathic membranous nephropathy (IMN) as a single organ autoimmune disease is a main cause of nephrotic syndrome in adults which is determined through autoantibodies to podocytes proteins. Th17/regulatory T (Treg) balance has emerged as a prominent factor in the regulation of autoimmunity. In this study, we evaluated the balance of Th17 and Treg cells, expression level of related master transcription factors, cytokines and microRNAs in mononuclear cells of peripheral blood of 30 patients with IMN and 30 healthy individuals before treatment. No significant variation was observed in Th17 cell frequency, retinoic acid receptor-related orphan nuclear receptor γt (RORɣt), signal transducer and Activator of transcription 3(STAT3), IL-17, and IL-23, while IL-21, IL-4, and IL-10 had significant increase in mRNA expression and protein level of peripheral blood mononuclear cells in IMN cases. Reduction in the percentage of Treg cells was also accompanied with significantly decreased expression of Forkhead box P3(FOXP3) and Transforming growth factor beta(TGF-β) in IMN patients compared to the control group. Our study revealed that Th17 cells themselves might not be engaged in the pathogenesis of newly diagnosed patients with IMN; however, decreased T reg cells and increased ratio of Th17/Treg lymphocytes might display a role in the pathogenesis of IMN before treatment.

The expression and clinical significance of three lncRNAs in patients with a missed abortion

Missed abortions are common complications that occur in early pregnancy, and impaired trophoblast functions have been indicated to be associated with their pathogenesis. The long noncoding RNAs (lncRNAs) Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1), HOX Transcript Antisense RNA (HOTAIR) and Maternally expressed gene 3 (MEG3) have been demonstrated to serve a crucial regulatory role in the mobility of trophoblast cells and embryo implantation. However, the expression profile and role of each of these three lncRNAs in patients with a missed abortion remain unclear. The expression of MALAT1, HOTAIR, and MEG3 in decidual and villous tissues from 26 patient exhibiting a missed abortion and 26 healthy controls was detected using reverse-transcription quantitative PCR. Serum TNF-α, IL-1β, IL-6 and IL-10 levels were measured using ELISA, and serum estradiol and progesterone levels were measured with electrochemiluminescence immunoassays. Additionally, the correlations between lncRNA expression and the levels of cytokines and hormones were further analyzed. MALAT1, HOTAIR and MEG3 expression was significantly higher in villous tissues of patients exhibiting a missed abortion compared with healthy controls. MALAT1 expression was higher in decidual tissues of patients exhibiting a missed abortion compared with healthy controls. Serum IL-10 levels were significantly lower in patients exhibiting a missed abortion compared with healthy controls. Serum estradiol and progesterone levels were significantly lower in the group of patients exhibiting a missed abortion compared with the control group. Furthermore, MALAT1 expression in villous tissue was inversely related to serum progesterone levels. The results of the current study suggest that MALAT1 may be associated with the pathogenesis of missed abortions.