Elevated Serum Level of IL-35 Associated with the Maintenance of Maternal-Fetal Immune Tolerance in Normal Pregnancy

Exploring the Immunological Aspects and Treatments of Recurrent Pregnancy Loss and Recurrent Implantation Failure

Recurrent pregnancy loss (RPL) is defined as the occurrence of two or more consecutive pregnancy losses before 24 weeks of gestation. It affects 3-5% of women who are attempting to conceive. RPL can stem from a variety of causes and is frequently associated with psychological distress and a diminished quality of life. By contrast, recurrent implantation failure (RIF) refers to the inability to achieve a successful pregnancy after three or more high-quality embryo transfers or at least two instances of egg donation. RIF shares several causative factors with RPL. The immunological underpinnings of these conditions involve alterations in uterine NK cells, reductions in M2 macrophages and myeloid-derived suppressor cells, an increased Th1/Th2 ratio, a decreased Treg/Th17 ratio, the presence of shared ≥3 HLA alleles between partners, and autoimmune disorders. Various therapeutic approaches have been employed to address these immunological concerns, achieving varying degrees of success, although some therapies remain contentious within the medical community. This review intends to explore the immunological factors implicated in RPL and RIF and to analyze the immunological treatments employed for these conditions, which may include steroids, intravenous immunoglobulins, calcineurin inhibitors, anti-TNF antibodies, intralipid infusions, granulocyte colony-stimulating factor, and lymphocyte immunotherapy.

B cells: roles in physiology and pathology of pregnancy

B cells constitute a diverse and adaptable immune cell population with functions that can vary according to the environment and circumstances. The involvement of B cells in pregnancy, as well as the associated molecular pathways, has yet to be investigated. This review consolidates current knowledge on B cell activities and regulation during pregnancy, with a particular focus on the roles of various B cell subsets and the effects of B cell-derived factors on pregnancy outcomes. Moreover, the review examines the significance of B cell-associated autoantibodies, cytokines, and signaling pathways in relation to pregnancy complications such as pregnancy loss, preeclampsia, and preterm birth.

Efficacy of mesenchymal stromal cells in the treatment of unexplained recurrent spontaneous abortion in mice: An analytical and systematic review of meta-analyses

OBJECTIVES

Unexplained recurrent spontaneous abortion (URSA) remains an intractable reproductive dilemma due to the lack of understanding of the pathogenesis. This study aimed to evaluate the preclinical evidence for the mesenchymal stromal cell (MSC) treatment for URSA.

METHODS

A meticulous literature search was independently performed by two authors across the Cochrane Library, EMBASE, and PubMed databases from inception to April 9, 2023. Each study incorporated was assessed using the Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) risk of bias tool. The amalgamated standardized mean difference (SMD) accompanied by 95% confidence interval (CI) were deduced through a fixed-effects or random-effects model analysis.

RESULTS

A total of ten studies incorporating 140 mice were subjected to data analysis. The MSC treatment yielded a significant reduction in the abortion rate within the URSA model (OR = 0.23, 95%CI [0.17, 0.3], P<0.00001). Moreover, it elicited a positive modulatory impact on the expression profiles of several inflammatory cytokines in the decidual tissue of URSA murine models, inclusive of IL4 (SMD 1.63, 95% CI [0.39, 2.86], P = 0.01), IL10 (SMD 1.60, 95% CI [0.58, 2.61], P = 0.002), IFN-γ (SMD -1.66, 95%CI [-2.79, -0.52], P = 0.004), and TNF-α (SMD -1.98, 95% CI [-2.93, -1.04], P< 0.0001). Subgroup analyses underscored that the administration mode of intraperitoneal and uterine horn injections, and sources of bone MSCs and adipose-derived MSCs contributed positively to the expression of IL4, IL10, and decreased the expression of IFN-γ in decidual tissue of URSA (P<0.05). Conversely, the tail vein injections subgroup was observed with no statistical significance (P>0.05).

CONCLUSIONS

The findings underscore the considerable potential of MSCs in URSA therapy. Nonetheless, the demand for enhanced transparency in research design and direct comparisons between various MSC sources and administration routes in URSA is paramount to engendering robust evidence that could pave the way for successful clinical translation.

Biomolecules Involved in Both Metastasis and Placenta Accreta Spectrum-Does the Common Pathophysiological Pathway Exist?

The process of epithelial-to-mesenchymal transition (EMT) is crucial in the implantation of the blastocyst and subsequent placental development. The trophoblast, consisting of villous and extravillous zones, plays different roles in these processes. Pathological states, such as placenta accreta spectrum (PAS), can arise due to dysfunction of the trophoblast or defective decidualization, leading to maternal and fetal morbidity and mortality. Studies have drawn parallels between placentation and carcinogenesis, with both processes involving EMT and the establishment of a microenvironment that facilitates invasion and infiltration. This article presents a review of molecular biomarkers involved in both the microenvironment of tumors and placental cells, including placental growth factor (PlGF), vascular endothelial growth factor (VEGF), E-cadherin (CDH1), laminin γ2 (LAMC2), the zinc finger E-box-binding homeobox (ZEB) proteins, αVβ3 integrin, transforming growth factor β (TGF-β), β-catenin, cofilin-1 (CFL-1), and interleukin-35 (IL-35). Understanding the similarities and differences in these processes may provide insights into the development of therapeutic options for both PAS and metastatic cancer.

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

PURPOSE OF THE REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Cytokine see-saw across pregnancy, its related complexities and consequences

During pregnancy, a woman's immune system adapts to the changing hormonal concentrations, causing immunologic transition. These immunologic changes are required for a full-term pregnancy, preserving the fetus' innate and adaptive immunity. Preterm labor, miscarriage, gestational diabetes mellitus, and pre-eclampsia are all caused by abnormal cytokine expression during pregnancy and childbirth. A disruption in the cytokine balance can lead to autoimmune diseases or microbiologic infections, or to autoimmune illness remission during pregnancy with postpartum recurrence. The cytokine treatments are essential and damaging to the developing fetus. The current review summarizes the known research on cytokine changes during pregnancy and their possible consequences for pregnant women. Studies suggest that customizing medication for each woman and her progesterone levels should be based on the cytokine profile of each pregnant woman. Immune cells and chemicals play an important function in development of the placenta and embryo. During pregnancy, T cells divide and move, and a careful balance between proinflammatory and anti-inflammatory cytokines is necessary. The present review focuses on the mother's endurance in generating fetal cells and the immunologic mechanism involved.

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

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

At Embryo Implantation Site IL-35 Secreted by Trophoblast, Polarizing T Cells towards IL-35+ IL-10+ IL-4+ Th2-Type Cells, Could Favour Fetal Allograft Tolerance and Pregnancy Success

We investigated the role of rhIL-35, at low concentrations compatible with those produced by human trophoblast cells (less than 1 ng/mL), on human T helper (Th) cell functions and the presence of decidual IL-35-producing Th cells in human pregnancy. We found that human trophoblast cells produced IL-35 but not IL-4 or IL-10. RhIL-35, at concentrations produced by human trophoblasts, polarized T cells towards IL-35+, IL-10+, IL-4+ Th2-type cells and to Foxp3+ EBI3+ p35+ T reg cells producing IL-35 but not IL-10 and IL-4. Moreover, rhIL-35 at low concentrations did not suppress the proliferation of Th cells but stimulated IL-4 and IL-10 production by established Th clones. In particular, Th1-type clones acquired the capacity to produce IL-4. In addition, purified human trophoblast cell supernatants containing IL-35 upregulated IL-4 and IL-10 production by Th clones. Finally, IL-35+, IL-10+, IL-4+ Th2-type cells, which were found to be induced by low concentrations of IL-35 compatible with those produced by human trophoblasts, are exclusively present in the decidua of a successful pregnancy and at the embryo implantation site, suggesting their stringent dependence on trophoblast cells. Thus, the proximity of Th cells to IL-35-producing trophoblasts could be the determining factor for the differentiation of IL-35+, IL-10+, IL-4+ Th2-type cells that are crucial for human pregnancy success.

Maternal Serum Cytokine Concentrations in Healthy Pregnancy and Preeclampsia

The maternal immune response is essential for successful pregnancy, promoting immune tolerance to the fetus while maintaining innate and adaptive immunity. Uncontrolled, increased proinflammatory responses are a contributing factor to the pathogenesis of preeclampsia. The Th1/Th2 cytokine shift theory, characterised by bias production of Th2 anti-inflammatory cytokine midgestation, was frequently used to reflect the maternal immune response in pregnancy. This theory is simplistic as it is based on limited information and does not consider the role of other T cell subsets, Th17 and Tregs. A range of maternal peripheral cytokines have been measured in pregnancy cohorts, albeit the changes in individual cytokine concentrations across gestation is not well summarised. Using available data, this review was aimed at summarising changes in individual maternal serum cytokine concentrations throughout healthy pregnancy and evaluating their association with preeclampsia. We report that TNF-α increases as pregnancy progresses, IL-8 decreases in the second trimester, and IL-4 concentrations remain consistent throughout gestation. Lower second trimester IL-10 concentrations may be an early predictor for developing preeclampsia. Proinflammatory cytokines (TNF-α, IFN-γ, IL-2, IL-8, and IL-6) are significantly elevated in preeclampsia. More research is required to determine the usefulness of using cytokines, particularly IL-10, as early biomarkers of pregnancy health.

Tryptophan catabolism to serotonin and kynurenine in women undergoing in-vitro fertilization

This cross-sectional clinical study was designed to explore the impact of tryptophan-kynurenine and tryptophan-serotonin (5 HT) pathways on reproductive performance during in vitro fertilization (IVF). Paired serum and follicular fluid (FF) samples were obtained from 64 consecutive IVF patients. The analysis was done by using LC-MS/MS. Ovarian hyperstimulation resulted in decreased serum tryptophan (p<0.004), 5-HT (p<0.049) and kynurenine (p<0.001). FF levels of tryptophan (R=0.245, p<0.051), kynurenine (R=0.556, p<0.001) and 5-HT (R=0.523, p<0.001) were positively related to their respective serum levels. Clinical pregnancy was associated with higher serum 5-HT (p<0.045) and FF 5-HT (p<0.020) and lower kynurenine to 5-HT ratio (p<0.024). Chemical pregnancy was also positively related to FF 5-HT (R=0.362, p<0.024). Moreover, there was a direct relationship of the number of mature oocytes to the FF 5-HT (R=0.363, p<0.020) but it was inversely related to FF tryptophan to 5-HT and FF kynurenine to 5-HT ratios (R=-0.389, p<0.016 and R=-0.337, p<0.036, respectively). Multivariate logistic regression revealed that the number of mature oocytes was significantly influenced by FF 5-HT (?=0.473, p<0.001). In IVF patients ovarian hyperstimulation results in a reduction of the availability of tryptophan to catabolic pathways to kynurenine and 5-HT. Outcome measures improved significantly when 5-HT predominated over kynurenine.

Serum level of interleukin-35 as a potential prognostic factor for gastric cancer

AIMS

Interleukin-35 (IL-35), a novel anti-inflammatory cytokine, has recently been implicated in tumor development, progression, and survival. However, the relationship between serum IL-35 levels and gastric cancer (GC) is inconclusive. Here, we performed this study to clarify the role of serum level of IL-35 in GC patients.

METHODS

We enrolled 180 GC patients and 170 healthy controls and used enzyme-linked immunosorbent assay to detect serum IL-35 levels. The clinical relevance between IL-35 and clinical pathology parameters was assessed. Univariate and multivariate logistic regressions were used to determine the feasibility of IL-35 as a clinical biomarker.

RESULTS

We observed that serum IL-35 levels were significantly higher in GC patients (17.559 ± 13.266 pg/mL) than in healthy controls (8.077 ± 3.801 pg/mL, P < .001). High serum IL-35 levels were significantly associated with clinical stage (P = .048) and Helicobacter pylori (HP) infection (P < .001). The Kaplan-Meier survival analysis indicated that patients in the high-IL-35 group had poor overall survival (OS) and progression-free survival (PFS) (median OS: 26.0 vs 36.0 months, P < .001; median PFS: 18.0 vs.26.0 months, P = .044). Multivariate analyses demonstrated that serum IL-35 was an independent prognostic factor for GC (OS: hazard ratio [HR] = 1.031 [95% CI, 1.017-1.045], P < .001; PFS: HR = 1.029 [95% CI, 1.015-1.043], P < .001).

CONCLUSIONS

High serum IL-35 levels are associated with poor disease prognosis in GC patients, and it may be become a new and promising biomarker for prognosis of gastric cancer.

Evaluation of Transforming Growth Factor-β1 and Interleukin-35 Serum Levels in Patients with Placenta Accreta

OBJECTIVE

Placenta accreta is a pregnancy-related disorder with extreme trophoblast invasion and the adherence of the placenta to the uterine wall. This study aimed to investigate the serum level of transforming growth factor-beta 1 (TGF-β1) and interleukin (IL)-35 in patients with placenta accreta.

METHODS

Thirty-one women with placenta accreta and 57 healthy pregnant women were enrolled. The serum levels of TGF-β1 and IL-35 were measured using the enzyme-linked immunosorbent assay method.

RESULTS

The serum levels of both TGF-β and IL-35 were significantly higher in the placenta accreta group compared with the group of healthy women (1082.48 pg/mL vs 497.33 pg/mL and 4541.14 pg/mL vs 1306.04 pg/mL; P <.001, respectively). Moreover, the level of TGF-β1 positively correlated with the IL-35 level but other factors such as age, gestations, live births, and abortions did not correlate with IL-35 and TGF-β1 levels.

CONCLUSION

The serum levels of IL-35 and TGF-β1 may contribute to the pathogenesis of placenta accreta and could be considered as potential targets in clinical and diagnostic approaches.

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.

Associations between microRNA (miR-25, miR-32, miR-125, and miR-222) polymorphisms and recurrent implantation failure in Korean women

Background

Recurrent implantation failure (RIF) is the failure of embryos to implant more than two times in a given individual. There is debate about a precise definition for RIF, but we consider more than two implantation failures for individuals who undergo in vitro fertilization-embryo transfer (IVF-ET) to constitute RIF. There are many potential reasons for RIF, including embryonic factors, immunological factors, uterine factors, coagulate factors, and genetic factors. Genetic variation has been suggested as one of the contributing factors leading to RIF, and a number of single-nucleotide polymorphisms (SNPs) have been reported to be associated with RIF. The recent elucidation of miRNA functions has provided new insight into the regulation of gene expression.

Methods

We investigated associations between polymorphisms in four miRNAs and RIF in 346 Korean women: 118 patients with RIF and 228 controls. We determined the genotypes of the miRNAs in the study participants by polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) analysis. We analyzed the effects of genotypes, allele combinations, and environmental and clinical factors on the risk of RIF.

Results

The miR-25 T/miR-125aT/miR-222G (odds ratio (OR), 0.528; 95% confidence interval (CI), 0.282–0.990; P = 0.044) and miR-25 T/miR-125aT allele combinations were associated with a reduced risk of RIF. The miR-25 T/miR-32C/miR-125aC/miR-222 T allele combination was associated with an increased risk of RIF. The miR-222GT+TT genotypes interacted with high prothrombin time (≥ 12 s) to increase the risk of RIF.

Conclusions

MicroRNA polymorphisms are significantly different between patients that experience RIF and healthy controls. Combinations of microRNA polymorphisms were associated with the risk of RIF. Interactions between environmental factors and genotypes increased the risk of RIF in Korean women.

Patients with idiopathic recurrent miscarriage have abnormally high TGFß+ blood NK, NKT and T cells in the presence of abnormally low TGFß plasma levels

Background

Previously, we demonstrated up-regulated activated CD4+ and CD8+ T lymphocytes as well as up-regulated cytotoxic NK cells in the blood of patients with idiopathic recurrent miscarriage. In the present study, we tried to identify deficiencies in counter-regulating immune mechanisms of these patients.

Method

Cytokines were determined in NK cells and in plasma samples of 35 healthy controls, 33 patients with idiopathic recurrent miscarriage, 34 patients with end stage renal disease, 10 transplant patients early and 37 transplant patients late post-transplant using flow-cytometry and luminex. In addition, cytokines were studied in supernatants of cell cultures with peripheral blood mononuclear cells stimulated in-vitro with tumor cell line K562.

Results

Patients with idiopathic recurrent miscarriage exhibited the highest absolute cell counts of circulating TGFß1+ NK, NKT and T lymphocytes and the lowest TGFß1 plasma levels of all study groups (for all p < 0.050). In-vitro, peripheral blood mononuclear cells of patients with idiopathic recurrent miscarriage showed high spontaneous TGFß1 production that could not be further increased by stimulation with K562, indicating increased consumption of TGFß1 by activated cells in the cell culture. Moreover, patients with idiopathic recurrent miscarriage had abnormally high IL4+ as well as abnormally high IFNy+ NK cells (p < 0.010) but similar IL10+ NK cell numbers as female healthy controls and showed the lowest plasma levels of IL10, TGFß3, IL1RA, IL1ß, IL5, IL6, IL8, IL17, TNFα, GM-CSF, TPO and VEGF and the highest plasma levels of G-CSF, FGF-basic, CCL3 and CXCL5 as compared to female HC and female transplant recipients (for all p < 0.050).

Conclusions

Patients with idiopathic recurrent miscarriage show an activated immune system that can hardly be stimulated further and cannot be efficiently down-regulated by up-regulated TGFß1+ and IL4+ NK, NKT and T lymphocytes which are present concomitantly in these patients. The strongly decreased TGFß and IL10 plasma levels indicate deficient down-regulation and reflect a dysbalance of the immune system in patients with idiopathic recurrent miscarriage. These findings may be relevant for explaining the pathogenesis of idiopathic recurrent miscarriage.

Electronic supplementary material

The online version of this article (10.1186/s12865-019-0290-3) contains supplementary material, which is available to authorized users.

Evaluation of IL-17 and IL-35 Serum Levels in Patients with Preeclampsia

BACKGROUND

Pre-eclampsia (PE) is the most common pregnancy complication affecting 2-8% of all pregnancies. PE could lead to maternal and prenatal morbidity. Imbalanced cytokine network and altered levels of several inflammatory and anti-inflammatory cytokines have been reported in PE. Because of scare information regarding the roles of IL-17 and IL-35 in PE, the current study aimed to investigate the serum level of these cytokines in a group of Iranian women suffering from PE.

METHODS

Serum samples were collected from 100 pre-eclamptic and 100 healthy pregnant women. Patients and controls were matched for age, ethnicity and body mass index. The level of IL-35 and IL-17 were evaluated by ELISA technique. T test and one-way ANOVA with Tukey Post-Hoc test were used for analysis and p<0.05 were assumed significant.

RESULTS

The serum level of IL-35 was increased in pre-eclamptic subjects as compared with healthy pregnant women (p<0.001). There was no significant difference in the serum level of IL-17 between pre-eclamptic and healthy pregnant women (p=0.73). Moreover, the results of the present study also showed that the pregnant women with severe pre-eclampsia had higher level of IL-35 in their sera when compared to those with mild form of the disease (p<0.001). In addition, the serum level of IL-35 was significantly elevated in women with higher proteinuria (p<0.001).

CONCLUSION

Based on the our results, it seems that elevated levels of IL-35 in sera of pre-eclamptic women might work as a marker to evaluate the severity of the preeclampsia.

Associations of maternal oestradiol, cortisol, and TGF-β1 plasma concentrations with thyroid autoantibodies during pregnancy and postpartum

BACKGROUND

Thyroid physiology and autoimmunity are altered in pregnancy. While oestradiol, cortisol, and TGF-β1 are implicated in these phenomena outside pregnancy, their associations with thyroid autoantibodies during pregnancy and postpartum are not thoroughly examined. This study aimed to unravel their eventual associations during pregnancy and postpartum in the same cohort of 93 pregnant women studied prospectively from 2015 to 2017.

METHODS

Blood samples were drawn at the 24th and the 36th gestational week and at the 1st postpartum week for measurements of thyroid hormones, TSH, anti-TPO, anti-Tg, oestradiol, cortisol, and TGF-β1.

RESULTS

Serum anti-TPO was greater (P < 0.05) at the 1st postpartum than at the 24th and 36th gestational weeks. At the 36th gestational week, cortisol was greater (P < 0.05) and TGF-β1 lower (P < 0.05) than at the 24th gestational and the 1st postpartum weeks. At the 1st postpartum week, cortisol correlated negatively with anti-Tg (r = -0.419) (P < 0.05). ΔTGF-β1 was the best negative and Δoestradiol the best positive predictor of the 1st postpartum week anti-TPO (P < 0.05, b = -0.509; P < 0.05, b = 0.459 respectively).

CONCLUSIONS

At postpartum, increased TGF-β1 is related to a less pronounced anti-TPO increase as compared to the 3rd trimester, suggesting an immunosuppressive role for TGF-β1. During pregnancy and postpartum, oestradiol, cortisol, and TGF-β1 are associated with suppression of thyroid autoantibodies.

Immunological Basis for Recurrent Fetal Loss and Pregnancy Complications

Pregnancy stimulates an elaborate assortment of dynamic changes, allowing intimate approximation of genetically discordant maternal and fetal tissues. Although the cellular and molecular details about how this works remain largely undefined, important clues arise from evaluating how a prior pregnancy influences the outcome of a future pregnancy. The risk of complications is consistently increased when complications occurred in a prior pregnancy. Reciprocally, a prior successful pregnancy protects against complications in a future pregnancy. Here, we summarize immunological perturbations associated with fetal loss, with particular focus on how both harmful and protective adaptations may persist in mothers. Immunological aberrancy as a root cause of pregnancy complications is also considered, given their shared overlapping risk factors and the sustained requirement for averting maternal-fetal conflict throughout pregnancy. Understanding pregnancy-induced immunological changes may expose not only new therapeutic strategies for improving pregnancy outcomes but also new facets of how immune tolerance works that may be applicable to other physiological and pathological contexts.

Vitamin D, autoimmunity and recurrent pregnancy loss: More than an association

Recurrent pregnancy loss (RPL) affects close to 1% of couples; however, the etiology is known in only about 50% of the cases. Recent studies show that autoimmune dysregulation is a probable cause of RPL, which in some cases may be overlooked. In order for a pregnancy to proceed to term, early modulation of immunologic response is required to induce tolerance to the semi-allogenic fetus. Certain subsets of both the innate and adaptive immune responses play a role in the induction of fetomaternal tolerance. A relatively predominant T-cell helper (Th) 2 and T regulatory (Treg) cell population seem to favor a better pregnancy outcome, whereas Th1 and Th17 cell populations appear to have an opposite effect. Lately, the role of vitamin D in the modulation of immune response was established. Vitamin D has been shown to promote a more favorable environment for pregnancy through various mechanisms, such as enhancement of the shift toward Th2 cells and regulation of immune cell differentiation and cytokine secretion. Therefore, it seems that vitamin D deficiency sways the balance toward a worse outcome and may play a part in recurrent pregnancy loss. This review sheds light on the immunologic changes, which occur in early pregnancy and the regulatory role vitamin D has in the maintenance of this delicate balance.

Expression and significance of dendritic cells and Th17/Treg in serum and placental tissues of patients with intrahepatic cholestasis of pregnancy

PURPOSE

Dendritic cells (DCs) are involved in immune system, which can also regulate the differentiation of T helper 17 (Th17) and regulatory T cells (Treg). DCs and Th17/Treg participate in preeclampsia and recurrent spontaneous abortion (RSA), but there is still lack of research in intrahepatic cholestasis of pregnancy (ICP). The aim was to evaluate the expression and significance of CD83+DCs, CD1a+DCs, interleukin-17 (IL-17) and IL-35 in serum and placental tissues of patients with ICP.

METHODS

Thirty cases of mild ICP, 25 cases of severe ICP were selected, and 30 cases of normal pregnant women were selected as control group. Enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) were used to detect the expression of CD83+DCs, CD1a+DCs, IL-17 and IL-35 in serum and placenta tissues, respectively.

RESULTS

There were more CD83+DCs, IL-17 expressed in placenta from women with ICP than in normal pregnancies, while the number of decidual CD1a+DCs, IL-35 was significantly lower in ICP than in normal pregnant women. The comparison within three groups had statistical difference (p < .05). Serum CD83+DCs and CD1a+DCs levels had no significance. IL-17 was higher in ICP, while IL-35 was lower.

CONCLUSIONS

DCs are involved in damaging the maternal-fetal immune tolerance by changing the phenotype and mature state, which may affect the differentiation of Th17/Treg to cause ICP.

Placental immune state shifts with gestational age

PROBLEM

Placental immunologic functions are implicated in both the maintenance of a healthy pregnancy and the pathogenesis of obstetric complications. Immune populations at the maternal-fetal interface are hypothesized to support fetomaternal tolerance, defend the fetus from infection, and contribute to labor initiation. Despite the many potential roles of placental immune cells in normal and abnormal pregnancy, little is known about placental immune population dynamics over gestation, particularly near parturition.

METHOD OF STUDY

A daily placental immune cell census was established in a murine model by flow cytometry from mid to late gestation and compared to the maternal systemic immune census. Shifts in the placental immune state were further characterized through cytokine ELISAs.

RESULTS

The placental immune census is distinct from the maternal systemic immune census, although the cells are primarily maternal in origin. Near term parturition, the placenta contains fewer CD11c-positive myeloid cells and regulatory T cells, and there is a concurrent decrease in placental IL-9 and IL-35.

CONCLUSION

The immune profile of the placenta demonstrates a decrease in both regulatory immune cell types and cytokines late in gestation. Establishing the placental immune population dynamics over a healthy pregnancy will allow future investigation of placental immune cells during abnormal pregnancy.

Elevated level of interleukin-35 in colorectal cancer induces conversion of T cells into iTr35 by activating STAT1/STAT3

IL-35 is a novel heterodimeric and inhibitory cytokine, composed of interleukin-12 subunit alpha (P35) and Epstein-Barr virus -induced gene 3 (EBI3). IL-35 has been reported to be produced by a range of cell types, especially regulatory T cells, and to exert immunosuppressive effects via the STATx signaling pathway. In this study, we demonstrated that IL-35 expression was elevated in both serum and tumors in patients with colorectal cancer. IL-35 mainly expressed in CD4⁺ T cells in human colorectal cancer tumors and adjacent tissues. Increased IL-35 expression in tumor-adjacent tissues was significantly associated with tumor metastasis. IL-35 inhibited the proliferation of CD4⁺CD25⁻ T effector cells in vitro in a dose-dependent manner, and its suppression was partially reversed by applying IL-35-neutralizing antibodies. IL-35 treatment activated the phosphorylation of both STAT1 and STAT3 in human CD4⁺ T cells. Meanwhile, IL-35 induced a positive feedback loop to promote its own production. We observed that Tregs obtained from colorectal cancer patients were capable of inducing more IL-35 production. In addition, EBI3 promoter-driven luciferase activity was higher than that of the mock plasmid after IL-35stimulation. Thus, our study indicates that the high level of IL-35 in colorectal cancer promotes the production of IL-35 via STAT1 and STAT3, which suppresses T cell proliferation and may participate in tumor immunotolerance.

Interleukin-35 Level Is Elevated in Patients with Chronic Hepatitis B Virus Infection

Backgrounds: As one of the major public health problems, the hepatitis B virus (HBV) infection would activate the immune system. The outcome of HBV infection was affect significantly by the interactions between HBV and host immune response. Interleukins play important role in anti-viral immunity. Here we investigated the role of interleukin-35 (IL-35) in chronic HBV infection patients. Methods/Results: Serum IL-35 in 72 chronic hepatitis B virus infection patients and 41 healthy control subjects were analyzed by ELISA assay. The mRNA level of IL-35 in PBMCs was determined by RT-qPCR. In this study, we found that both protein and mRNA levels of IL-35 were significantly decreased in chronic HBV patients compared to the healthy controls. Furthermore, the statistical analysis found that serum IL-35 was significantly associated with HBV DNA (P =0.0158), ALT (P =0.0003), AST (P =0.0216), TB (P =0.0270) and AFP (P =0.0369). Importantly, correlation analysis also found that serum IL-35 level was negatively correlated with HBV DNA copies, ALT, AST, TB and AFP. Meanwhile, IL-35 treatment inhibited the level of HBV DNA, HBsAg and HBeAg in HepAD38 cells. Conclusion: Our study identified that IL-35 may be a novel marker associated with HBV infection and hepatocytes injury. These data suggested the potential use of IL-35 in the HBV treatment.

T helper cell subsets and related cytokines in infertile women undergoing in vitro fertilization before and after seminal plasma exposure

Objective

In vitro fertilization (IVF) is a well-known method for the treatment of infertility. The present study aimed to compare the differences between infertile women with successful and unsuccessful IVF outcomes regarding the expression of T helper (Th) cell transcription factors and a group of related cytokines before and after exposure to their husbands' seminal plasma.

Methods

This study was performed on 19 couples with unexplained infertility undergoing IVF treatment. Among the studied group, nine and 10 couples had successful and unsuccessful IVF outcomes, respectively. This study was carried out using real-time polymerase chain reaction.

Results

Before seminal plasma exposure, the expression levels of T-bet (p<0.007), interferon-γ (p=0.013), and tumor necrosis factor (TNF)-α (p=0.017) were higher in the infertile women with IVF failure than in those with successful IVF outcomes, while those of GATA3 (p<0.001), Foxp3 (p=0.001), and interleukin (IL)-35 (p<0.003) were lower. After seminal exposure, the expression of T-bet (p=0.02), Rorc (p<0.001), TNF-α (p=0.001), Foxp3 (p=0.02), and interferon-γ (p=0.001) increased in the unsuccessful IVF group, while the expression of Foxp3 (p=0.02), Rorc (p<0.001), IL-23 (p=0.04), IL-17 (p=0.02), IL-6 (p<0.001), transforming growth factor-β (p=0.01), and IL-35 (p<0.001) increased in the successful IVF group.

Conclusion

In summary, IVF failure was associated with imbalanced Th1/Th2/Th17/Treg responses. Moreover, our results show that seminal plasma might have a positive effect on IVF outcomes via changes in peripheral blood T cell subsets.

Interluekin-35 in Asthma and Its Potential as an Effective Therapeutic Agent

Interleukin- (IL-) 35 is a member of the IL-12 cytokine family and a heterodimeric protein formed by Epstein-Barr-induced gene 3 (EBI3) and IL-12p35. Emerging evidence shows that IL-35 is a key player in the regulation of cellular communication, differentiation, and inflammation. Altered IL-35 expression has been found in disease conditions such as cancer, rheumatoid arthritis, and, more recently, asthma. In cancer, IL-35 is involved in the regulation of tumorigenesis, cancer progression, and metastasis. In rheumatoid arthritis, IL-35 acts as a negative regulator of inflammation. Similarly, IL-35 also appears to suppress allergic inflammation in asthma. In an in vivo murine model of asthma, transfer of adenovirus-mediated IL-35 markedly reduced the degree of airway hyperresponsiveness (AHR) and inflammatory cell infiltration. Many studies have shown the involvement of IL-35 in a number of aspects of allergic inflammation, such as eosinophil and neutrophil recruitment as well as inhibition of inflammatory mediators of the Th2 subtype. However, the exact molecular mechanisms underlying the role of IL-35 in human asthma have yet to be fully elucidated. This review describes the current evidence regarding the role of IL-35 in the pathophysiology of asthma and evaluates the potential of IL-35 as a biomarker for airway inflammation and a therapeutic target for the treatment of asthma.

Differences in Cytokine Expression and STAT3 Activation between Healthy Controls and Patients of Unexplained Recurrent Spontaneous Abortion (URSA) during Early Pregnancy

Unexplained recurrent spontaneous abortion (URSA) is a common complication of pregnancy. Although tolerance of the maternal immune system is considered to be essential for a normal pregnancy, the precise mechanism underlying the pathogenesis of URSA remains to be fully elucidated, albeit it is known to involve inflammation. Here, we examine the relationship between the expression of inflammatory cytokines and the activation of downstream signaling pathways in URSA patients. Decidual and peripheral blood samples were collected from 30 URSA patients and from 30 women with normal early pregnancies. Western blot analysis was used to measure the expression levels of signal transducers and activators of transcription 3(STAT3), phosphorylated STAT3(p-STAT3), and interleukin-17 receptor(IL-17R) in the decidual samples. Enzyme-linked immunosorbent assay was used to assess the levels of IL-17, IL-10, IL-6, and IL-23 in the peripheral blood and decidual samples. In the URSA patients, the IL-10 expression levels were lower than those in the control subjects (P<0.05), whereas IL-6, IL-17, and IL-23 were all expressed at higher levels(P<0.05). Furthermore, the expression levels of IL-17R and p-STAT3 were higher in the URSA patients, exhibiting a trend similar to that of IL-23. Our finding of increased IL-23 expression in the deciduae and peripheral blood of patients with URSA suggest that this maybe a contributing factor to the pathogenesis of this disease. Likewise, STAT3 activation through its phosphorylation, which was associated with the IL-23 increase, may also be involved in URSA pathogenesis. However, the precise pathogenic mechanism requires further study.

What is wrong with the regulatory T cells and foetomaternal tolerance in women with recurrent miscarriages?

Couples of whom the woman has had a miscarriage have two major concerns: the cause and possible risk of recurrence. Unfortunately, a significant proportion of cases of recurrent miscarriage (RM) remain unexplained despite detailed investigation. Because data suggest that regulatory T cells (Treg) are involved in the maternal acceptance of the allogeneic foetus, RM could possibly be explained by a disturbance of the Treg network. The possible role of Tregs in RM is described in this review, as well as their potential application in diagnostics and therapeutic intervention trials.

Tryptophan metabolism, disposition and utilization in pregnancy

Tryptophan (Trp) requirements in pregnancy are several-fold: (1) the need for increased protein synthesis by mother and for fetal growth and development; (2) serotonin (5-HT) for signalling pathways; (3) kynurenic acid (KA) for neuronal protection; (4) quinolinic acid (QA) for NAD(+) synthesis (5) other kynurenines (Ks) for suppressing fetal rejection. These goals could not be achieved if maternal plasma [Trp] is depleted. Although plasma total (free + albumin-bound) Trp is decreased in pregnancy, free Trp is elevated. The above requirements are best expressed in terms of a Trp utilization concept. Briefly, Trp is utilized as follows: (1) In early and mid-pregnancy, emphasis is on increased maternal Trp availability to meet the demand for protein synthesis and fetal development, most probably mediated by maternal liver Trp 2,3-dioxygenase (TDO) inhibition by progesterone and oestrogens. (2) In mid- and late pregnancy, Trp availability is maintained and enhanced by the release of albumin-bound Trp by albumin depletion and non-esterified fatty acid (NEFA) elevation, leading to increased flux of Trp down the K pathway to elevate immunosuppressive Ks. An excessive release of free Trp could undermine pregnancy by abolishing T-cell suppression by Ks. Detailed assessment of parameters of Trp metabolism and disposition and related measures (free and total Trp, albumin, NEFA, K and its metabolites and pro- and anti-inflammatory cytokines in maternal blood and, where appropriate, placental and fetal material) in normal and abnormal pregnancies may establish missing gaps in our knowledge of the Trp status in pregnancy and help identify appropriate intervention strategies.