What is the role of regulatory T cells in the success of implantation and early pregnancy?

The aging ovary impairs acute stroke outcomes

In experimental stroke, ovariectomized (OVX) adult rats have larger infarct volumes and greater sensory-motor impairment as compared to ovary-intact females and is usually interpreted to indicate that ovarian hormones are neuroprotective for stroke. Previous work from our lab shows that middle-aged, acyclic reproductively senescent (RS) females have worse stroke outcomes as compared to adult (normally cycling) females. We hypothesized that if loss of ovarian estrogen is the critical determinant of stroke outcomes, then ovary-intact middle-aged acyclic females, who have reduced levels of estradiol, should have similar stroke outcomes as age-matched OVX. Instead, the data demonstrated that OVX RS animals showed better sensory-motor function after stroke and reduced infarct volume as compared to ovary-intact females. Inflammatory cytokines were decreased in the aging ovary after stroke as compared to non-stroke shams, which led to the hypothesis that immune cells may be extravasated from the ovaries post-stroke. Flow cytometry indicated reduced overall T cell populations in the aging ovary after middle cerebral artery occlusion (MCAo), with a paradoxical increase in regulatory T cells (Tregs) and M2-like macrophages. Moreover, in the brain, OVX RS animals showed increased Tregs, increased M2-like macrophages, and increased MHC II + cells as compared to intact RS animals, which have all been shown to be correlated with better prognosis after stroke. Depletion of ovary-resident immune cells after stroke suggests that there may be an exaggerated response to ischemia and possible increased burden of the inflammatory response via extravasation of these cells into circulation. Increased anti-inflammatory cells in the brain of OVX RS animals further supports this hypothesis. These data suggest that stroke severity in aging females may be exacerbated by the aging ovary and underscore the need to assess immunological changes in this organ after stroke.

The Role of T Cells in Ovarian Physiology and Infertility

Infertility affects one in six couples worldwide, with more than 48 million couples affected internationally. The prevalence of infertility is increasing which is thought to be attributed to delayed child-bearing due to socioeconomic factors. Since women are more prone to autoimmune diseases, we sought to describe the correlation between ovarian-mediated infertility and autoimmunity, and more specifically, the role of T cells in infertility. T cells prevent autoimmune diseases and allow maternal immune tolerance of the semi-allogeneic fetus during pregnancy. However, the role of T cells in ovarian physiology has yet to be fully understood.

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

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

Gene polymorphism associated with FOXP3, CTLA-4 and susceptibility to pre-eclampsia: a meta-analysis and trial sequential analysis

Previous studies have detected the correlation of polymorphisms in regulatory T cells associated genes FOXP3 and CTLA-4 with pre-eclampsia (PE) risk, but the results are inconsistent among studies. Eligible studies were retrieved in several database. Odds ratios (ORs) with 95% confidence intervals (CIs) were utilised to evaluate the relationship between FOXP3 rs3761548, FOXP3 rs2232365, CTLA-4 rs231775 polymorphisms, and PE susceptibility in the genetic models. The subgroup analysis and trial sequential analysis were performed. Twelve studies with a total of 4658 participants were included. There was a statistically significant association between FOXP3 rs3761548 polymorphism and PE within the recessive model in Asian (OR = 0.54, 95% CI = 0.34-0.86). Trial sequential analysis indicated sufficient proof of such association in the Asian population. This meta-analysis provides sufficient statistical evidence indicating an association between FOXP3 rs3761548 polymorphism and PE risk in Asian.IMPACT STATEMENTWhat is already known on this subject? FOXP3 and CTLA4 are markers of regulatory T cells which play a crucial role during a preeclamptic pregnancy.What do the results of this study add? Eleven studies with a total of 4658 participants were included. There was a statistically significant association between FOXP3 rs3761548 polymorphism and pre-eclampsia (PE) within the recessive model in Asian (OR = 0.54, 95% CI = 0.34-0.86). Trial sequential analysis indicated sufficient proof of such association in the Asian population. However, there was no enough evidence could proof significant association between FOXP3 rs2232365 or CTLA-4 rs231775 polymorphism and PE.What are the implications of these findings for clinical practice and/or further research? This meta-analysis provides sufficient statistical evidence indicating an association between FOXP3 rs3761548 polymorphism and PE risk in Asian. The findings in this study may provide a basis for the further study on FOXP3 rs3761548 polymorphism in future research.

Altered eutopic endometrial T-regulatory and T-helper 17 lymphocyte ratio in women with unexplained subfertility

PROBLEM

Perturbations in T-helper lymphocyte profiles have previously been associated with endometriosis related subfertility and conception failure. Hence a retrospective in vitro study was conducted to evaluate the relationship between T-regulatory (Treg) and T-helper 17 (Th17) lymphocytes in the eutopic endometrium of women with unexplained subfertility and correlate these profiles to their conception status.

METHOD OF STUDY

Eutopic endometrial biopsies were collected during the mid-secretory phase of the menstrual cycle, from women with unexplained subfertility. These samples were evaluated immunohistochemically for Treg and Th17 lymphocytes as well as the related proinflammatory cytokine, Interleukin-17 (IL-17). These eutopic endometrial T lymphocyte subpopulations were compared to the patients' conception status in subsequent cycles.

RESULTS

Though Treg cells were not indicative of conception success in subsequent cycles, patients who maintained their subfertile (no conception) status were observed to have a higher Th17 cell count in their eutopic endometrium. The ratio of Treg:Th17 cell counts was significantly correlated to patient conception status as well. These trends stayed consistent irrespective of concurrent endometriosis.

CONCLUSION

Patients with a high proinflammatory Th17 lymphocyte profile and low Treg:Th17 ratio in their eutopic endometrium during the secretory phase of their menstrual cycle are more likely to not conceive in subsequent cycles.

Effects of treatment with hydroxychloroquine on the modulation of Th17/Treg ratio and pregnancy outcomes in women with recurrent implantation failure: clinical trial

AIM

The imbalance of Th17/Treg cells has been recently suggested as a new risk factors for recurrent implantation failure (RIF). Furthermore Th17/Treg cells are involved in immune regulation in peripheral blood and endometrial tissue of patients with RIF. In this research, we investigated the effects of Hydroxychloroquine (HCQ) on the level and function of Th17 and Treg cells in women with RIF. It may be possible to improve pregnancy outcomes by modulating high cytokine levels.

METHODS

Women with RIF received oral HCQ (n = 60) on day 4 of the menstrual cycle and continued until day 20 of the menstrual cycle and 2 days before embryo transfer and continued until the day of the pregnancy test, for a total of 16 days in another cycle. The serum levels of IL-17 and IL-10, the expression of transcription factors related to Th17 and Treg cells and the immune-reactivity of IL-17, IL-21 as Th17 related cytokines and IL-10, TGF- β as Treg related cytokines in endometrial tissues were evaluated by ELISA, real-time PCR, and fluorescent immunohistochemistry respectively.

Results: Treatment with HCQ down-regulated Th17 related cytokines and function and up-regulated Treg related cytokines and function significantly (p < .001). RORγt, the Th17 transcription factor, expression was down-regulated and FOXP-3, the T-reg transcription factor, expression was up-regulated. The biochemical pregnancy rate was not significantly different in RIF patients before and after treatment.

CONCLUSION

Our results demonstrated that the administration of HCQ in RIF women with immune cell disorders during pregnancy could affect the Th17/Treg ratio and enhance Treg and diminish Th17 responses which may be associated with successful pregnancy outcomes. However, significant difference in pregnancy outcomes was not observed in the present study.

Decreased expression of ligands of placental immune checkpoint inhibitors in uncomplicated and preeclamptic oocyte donation pregnancies

Oocyte donation (OD) pregnancies are characterized by a complete immunogenetic dissimilarity between mother and fetus, which requires enhanced immunoregulation compared to naturally conceived (NC) pregnancies. The trophoblast expresses co-inhibitory ligands crucial for regulation of the maternal T cell response. Therefore, we studied the role of placental immune checkpoint inhibitors for the establishment of fetal tolerance and their relation to the development of preeclampsia in OD compared to NC pregnancies. Placental tissue from uncomplicated OD (n = 21) and NC (n = 21) pregnancies, and OD (n = 9) and NC (n = 15) pregnancies complicated with preeclampsia were studied. Protein expression of co-inhibitory ligands PD-L1 and CD200 was double blind semi-quantitatively determined by immunohistochemistry. Messenger RNA expression of PD-L1, CD200 and indoleamine 2,3-dioxygenase (IDO) was determined using qPCR. Decreased PD-L1 and CD200 protein expression and increased IDO mRNA expression was observed in uncomplicated OD versus NC pregnancies (all p < 0.05). CD200 protein expression was positively correlated with PD-L1 expression in all groups, with the number of HLA total mismatches and with HLA class I mismatches in uncomplicated OD cases (all p < 0.05). Preeclamptic cases showed lower PD-L1 protein and CD200 protein and mRNA expression in OD compared to NC pregnancies (all p < 0.05). This study shows that signaling by co-inhibitory PD-L1 and CD200 and by immunosuppressive IDO is altered in the placenta of OD pregnancies, suggesting a contribution to the higher risk for preeclampsia. These insights provide future prospects in unraveling the immune paradox of oocyte pregnancy, which are applicable for better risk management and treatment of uncomplicated and preeclamptic pregnancies.

Difference of regulatory T cells, IL10, IL6, IFNγ, and IDO levels in female with high ASA and virgin: A research article

OBJECTIVE

The maternal immune system requires tolerance for conception to occur. It is not only the balance of Th 1/Th2 that plays a role in pregnancy, but also the regulatory T cells (Tregs) that regulate the important role in pregnancy. One cause of failure in pregnancy is due to immunological factors, including antisperm antibodies (ASA). About 10-30% of infertile couples are caused by ASA. Th1 secretes Interferon γ (IFNγ). IFNγ is also an inducer indoleamin 2,3 dioksigenase (IDO). Cooperation between Tregs and IDO will induce tolerance for pregnancy.Th2 secretes most ofinterleukin (IL)10. Increased IL10 and decreased IL6 occur during pregnancy. The aim of this study was to analyse difference of Tregs, IL10, IL6, IFNγ, and IDO levels in female with high ASA and virgin.

METHODS

Samples with high ASA were examined ASA titres using the husband's sperm auto-agglutination test (HSAaT) method.49 samples were analysed. Tregs were evaluated using flowcytometry with the human forkhead box P3 (FoxP3) staining kit of Biotech and Device.Level of IL10, IL6, and IFNγ was determined using an Abcam ELISA kit. Level of IDO was determined using an RnD ELISA kit. The data were analysed using the Mann-whitney tests.

RESULTS

There are differences in the Tregs population (p = 0.000<0.05) but there is no difference IL10, IL6, IFNγ, and IDO levels in female with high ASA and virgin (p 0.140 > 0.05, p 0.680 > 0.05, p 0.204 > 0.05, and p 0.362 > 0.05).

CONCLUSION

High ASA affects of the Tregs population but has no effect on cytokines IL10, IL6, IFNγ, and IDO.

The role of two common FOXP3 gene promoter polymorphisms in preeclampsia in a Turkish population: a case-control study

Preeclampsia (PE), which occurs in approximately 5% of pregnancies worldwide and constitutes clinically serious complications in 2-3%, is one of the leading causes of maternal and prenatal morbidity and mortality. Recent studies report that regulatory T (Treg) cells, which act as immunosuppressant, are associated with PE. It is clearly defined that FOXP3/Scurfin (Forkhead Box P3) is involved in the development and function of Tregs. However, there are different conclusions regarding the relationship between PE and FOXP3 gene polymorphisms for different populations. For this reason, in this study we investigate the association between FOXP3 gene promoter region polymorphisms and PE in a Turkish population 500 PE patients and 500 healthy pregnant women. Blood samples taken from pregnant women were studied by PCR-RFLP method. As a result, rs2232365 polymorphism was significantly associated with disease (p < .0001) while no significant association was found between rs3761548 polymorphism and the disease (p = .17). Based on these results, it is though that FOXP3 rs2232365 polymorphism may be predisposed to PE development in terms of Turkish population. However, further and functional studies are needed in terms of other polymorphisms and mutations.IMPACT STATEMENTWhat is already known on this subject? A number of recent publications suggest that Tregs may play a role in the pathogenesis of PE. It is known that a stable and high FOXP3 expression is required to maintain the suppressive T cell function of Tregs. Down regulation of FOXP3 in PE has been reported in many previous studies, but the mechanism is still uncertain.What do the results of this study add? Our study has examined two FOXP3 promoter region polymorphisms in terms of Turkish population for the first time. Rs2232365 polymorphism associated with the disease in heterozygous genotype.What are the implications of these findings for clinical practice and/or further research? It has been shown that FOXP3 gene promoter region polymorphisms may be associated with PE for Turkish population. Our results can be a guide for more detailed statistical evaluations and functional studies.

Ovarian stimulation does not influence the uterine immune environment in healthy infertile women

RESEARCH QUESTION

There is some controversy regarding the impact of ovarian stimulation on immune cells in women undergoing IVF. The study's aim was to determine whether ovarian stimulation affected immune uterine cells in healthy women undergoing IVF.

DESIGN

This prospective cohort study included 28 patients undergoing IVF and 47 healthy oocyte donors. Endometrial biopsies were taken in a natural cycle and after ovarian stimulation. All participants had a normal karyotype, pelvic ultrasound and cervical cytology results and thyroid-stimulating hormone concentration, as well as normal glucose and insulin concentrations and inherited and acquired thrombophilia test results. Screening tests including human papillomavirus were normal. Immune cells were analysed using three techniques: fluorescence-activated cell sorting, immunohistochemistry and gene expression. A human leukocyte antigen (HLA)-C tetramer was used as an 'artificial embryo'. The expression of genes including those for tumour necrosis factor (TNF)-α and interleukin-10 (IL-10) was analysed.

RESULTS

A comparison was made of the percentage and gene expression of CD56^brightCD16^- uterine natural killer (uNK), CD56^dimCD16⁺ natural killer cells, CD56^-CD16⁺ natural killer cells and TregCD25⁺CD4⁺FoxP3⁺ cells, uNK binding to the HLA-C tetramer, and TNF-α and IL-10 expression. No between- or within-group differences were observed in natural versus ovarian stimulation cycles.

CONCLUSIONS

Ovarian stimulation does not affect the uterine immune cell population or HLA-C binding in healthy women undergoing ovarian stimulation. Further studies are underway to find out if different responses might be seen in women with previous autoimmune disorders.

Angiogenesis, Lymphangiogenesis, and the Immune Response in South African Preeclamptic Women Receiving HAART

Purpose of the review: This review highlights the role of angiogenesis, lymphangiogenesis, and immune markers in human immunodeficiency virus (HIV)-associated preeclamptic (PE) pregnancies in an attempt to unravel the mysteries underlying the duality of both conditions in South Africa. Recent findings: Studies demonstrate that HIV-infected pregnant women develop PE at a lower frequency than uninfected women. In contrast, women receiving highly active anti-retroviral therapy (HAART) are more inclined to develop PE, stemming from an imbalance of angiogenesis, lymphangiogenesis, and immune response. Summary: In view of the paradoxical effect of HIV infection on PE development, this study examines angiogenesis, lymphangiogenesis, and immune markers in the highly HIV endemic area of KwaZulu-Natal. We believe that HAART re-constitutes the immune response in PE, thereby predisposing women to PE development. This susceptibility is due to an imbalance in the angiogenic/lymphangiogenic/immune response as compared to normotensive pregnant women. Further large-scale studies are urgently required to investigate the effect of the duration of HAART on PE development.

New Paradigm in the Role of Regulatory T Cells During Pregnancy

Semi-allogenic fetuses are not rejected by the maternal immune system because feto-maternal tolerance induced by CD4⁺CD25⁺FoxP3⁺ regulatory T (Treg) cells is established during pregnancy. Paternal antigen-specific Treg cells accumulate during pregnancy, and seminal plasma priming plays an important role in expanding paternal antigen-specific Treg cells in mouse models. Although paternal-antigen specific Treg cells have not been identified in humans, recent studies suggest that antigen-specific Treg cells exist and expand at the feto-maternal interface in humans. Studies have also revealed that reduction of decidual functional Treg cells occurs during miscarriage with normal fetal chromosomal content, whereas insufficient clonal expansion of decidual Treg cells is observed in preeclampsia. In this review, we will discuss the recent advances in the investigation of mechanisms underlying Treg cell-dependent maintenance of feto-maternal tolerance.

Therapeutic role of granulocyte colony-stimulating factor (G-CSF) for infertile women under in vitro fertilization and embryo transfer (IVF-ET) treatment: a meta-analysis

OBJECTIVE

The aim of this meta-analysis is to explore the beneficial role of granulocyte colony-stimulating factor (G-CSF) on infertile women under artificial reproduction technology treatment.

METHOD

Medline, Embase and ISI Web of Science databases were searched to identify relevant randomized control trials. Studies before July, 2017 were included for primary screening. Meta-analysis of the total and subgroup patients was conducted, and relative risks (RRs) and their 95% confidence intervals (95% CI) were calculated by a fixed-effect model if no heterogeneity (evaluated as I2 statistic) existed. Otherwise, a random-effects model was adopted. Subgroup analysis was performed by administrating route or clinical indication. Egger test and influence analysis were conducted to evaluate the publication bias and study power, respectively.

RESULTS

The final selection enrolled 10 RCTs, involving 1016 IVF-ET cycles (521 distributed to the G-CSF group and 495 to the control). Compared with control group, G-CSF administration could significantly improve clinical pregnancy rate (CPR, RR 1.89, 95% CI 1.53-2.33), while it had no beneficial effect on embryo implantation rate (IR, RR 1.84, 95% CI 0.84-4.03). The subgroup analysis by administration route showed that both uterine infusion and subcutaneous injection can produce a substantial increase in CPR, with the pooled RRs (95% CI) 1.46 (1.04-2.05) and 2.23 (1.68-2.95), respectively. Nevertheless, most of included RCTs dealt with the RIF subjects, and the pooled analysis of this data showed a higher PR and IR in G-CSF group as compared to that in the control, with the RRs (95% CI) 2.07 (1.64-2.61) and 1.52 (1.08-2.14), respectively. Egger regression test did not demonstrate any significance for the publication bias.

CONCLUSION

G-CSF administration has a beneficial role on the clinical outcome after embryo transfer by both routes of local infusion and systematic administration, especially for the cases with RIF. Further RCTs are needed to investigate the role of G-CSF in thin endometrium patients.

FoxP3 gene promoter polymorphism affects susceptibility to preeclampsia

BACKGROUND

Preeclampsia (PE) is a multifactorial pregnancy disorder and is a major cause of maternal morbidity and mortality. Despite intense study, the pathophysiology of preeclampsia remains enigmatic. Recent studies have reported that regulatory T cells (Tregs) is linked with PE. It is well identified that FoxP3/Scurfin is involved in development and function of Tregs. However, the association between PE and the FoxP3 gene polymorphism has not been sufficiently investigated. In this study, we hypothesized that polymorphisms of the FoxP3 may be related to PE.

METHODS

We assessed the relationship between four single-nucleotide polymorphisms (SNPs) in the FoxP3 genes with sequence-specific primers (PCR-SSP) in 81 PE patients and 90 age-matched controls.

RESULT

We identified significant difference of rs4824747 GG genotype frequency between the PE and control groups. Women with GG genotypes exhibited higher (OR=6.25, 95% CI=2.63-14.85; P<0.0001) risk of developing PE. None of the other investigated SNPs (rs2232365, rs3761547 and rs3761548) showed significant association with PE.

CONCLUSION

We suggest that FoxP3 polymorphisms (rs4824747) could be a potential contributor for the development of PE in Iranian women.

CD33(+) /HLA-DR(neg) and CD33(+) /HLA-DR(+/-) Cells: Rare Populations in the Human Decidua with Characteristics of MDSC

PROBLEM

Human pregnancy needs a remarkable local immune tolerance toward the conceptus. Myeloid-derived suppressor cells (MDSC) are important players promoting cancer initiation and progression by suppressing T-cell functions and thus inducing immune tolerance. Therefore, MDSC were expected within decidua.

METHODS

Subpopulations of CD33(+) immune cells were isolated from human early pregnancy decidua and characterized phenotypically and functionally by microscopy, FACS analysis, RT-PCR, Western blotting and in the coculture with T cells.

RESULTS

Decidua harbors CD33(+) /HLA-DR(neg) and CD33(+) /HLA-DR(+/-) cells which both express arginase, iNOS and IDO and a typical cytokine profile. Both subtypes potently suppress T-cell proliferation and therefore fulfill the criteria of MDSC.

CONCLUSION

We characterized a new population of CD33(+) /HLA-DR(neg) and CD33(+) /HLA-DR(+/-) cells in human early pregnancy decidua with properties of classical MDSC and thus potentially being an important player in immune tolerance in pregnancy.

Regulatory T-cells and preeclampsia: an overview of literature

Regulatory T-cells (Tregs) are key players in successful pregnancy and their deficiencies are implicated in pregnancy complications such as preeclampsia (PE), but the results are inconsistent among studies. This study aims to compile an overview of the studies about the associations of Tregs and PE risk and to provide recommendations for future research. A sensitive search of three databases including PubMed, Scopus and Google scholar (from 1995 to January 9, 2015) identified 636 unique titles. An accurate process of study selection, data extraction and method qualification were independently conducted by authors on retrieved papers. Seventeen papers met the inclusion criteria and were included in quality assessment. Regarding the source of Tregs, 14 studies assessed Tregs in peripheral blood, 2 studies in peripheral blood and decidua and one study in peripheral blood and umbilical cord blood. Despite variation in the combinations of markers and other aspects of the studies designs, remarkable constancy in the results of studies that measured Tregs as CD4+FoxP3+ or CD4+CD25+FoxP3+ cells (but not CD4+CD25(high/low)FoxP3+ markers) was found, which in broad terms showed a shift towards fewer Treg cells in PE. This review revealed an association between lower percentage of circulating CD4+FoxP3+ or CD4+CD25+FoxP3+ Tregs and the risk of PE. Given the above issue and regarding the high consistency of studies on reduction of suppressive activity of Tregs in PE, we have proposed a model in which the Tregs deficiency is a reflection of immune endocrine imbalance, which reverses maternal tolerance and results in development of preeclampsia.

Intrauterine insemination of cultured peripheral blood mononuclear cells prior to embryo transfer improves clinical outcome for patients with repeated implantation failures

Implantation failure is a major limiting factor in assisted reproduction improvement. Dysfunction of embryo–maternal immuno-tolerance pathways may be responsible for repeated implantation failures. This fact is supported by immunotropic theory stipulating that maternal immune cells, essentially uterine CD56+ natural killer cells, are determinants of implantation success. In order to test this hypothesis, we applied endometrium immuno-modulation prior to fresh embryo transfer for patients with repeated implantation failures. Peripheral blood mononuclear cells were isolated from repeated implantation failure patients undergoing assisted reproductive technology cycles. On the day of ovulation induction, cells were isolated and then cultured for 3 days and transferred into the endometrium cavity prior to fresh embryo transfer. This immunotherapy was performed on 27 patients with repeated implantation failures and compared with another 27 patients who served as controls. Implantation and clinical pregnancy were increased significantly in the peripheral blood mononuclear cell test versus control (21.54, 44.44 vs. 8.62, 14.81%). This finding suggests a clear role for endometrium immuno-modulation and the inflammation process in implantation success. Our study showed the feasibility of intrauterine administration of autologous peripheral blood mononuclear cells as an effective therapy to improve clinical outcomes for patients with repeated implantation failures and who are undergoing in vitro fertilization cycles.

Differential expression and regulation of Ido2 in the mouse uterus during peri-implantation period

Ido2 is involved in tryptophan catabolism and immunity, but its physiological functions remain poorly understood. This study was undertaken to examine the expression and regulation of Ido2 gene in mouse uterus during the peri-implantation period. The results showed that Ido2 mRNA was highly expressed on day 4 of pregnancy and in the delayed implantation uterus. On days 5-8 of pregnancy, a low level of Ido2 expression was observed in the uteri. Simultaneously, Ido2 mRNA was also lowly expressed in the decidualized uterus. In the uterine stromal cells, 8-Br-cAMP could inhibit the expression of Ido2 mRNA. Moreover, Ido2 mRNA expression was gradually decreased after the stromal cells were treated with estrogen and progesterone and reached a nadir at 96 h. Further study found that overexpression of Ido2 could downregulate the expression of decidualization marker genes PRL, IGFBP1, and Dtprp under in vitro decidualization, while inhibition of Ido2 with devo-1-methyl-tryptophan (D-1-MT) could upregulate the expression of these marker genes. Under in vitro decidualization, overexpression of Ido2 could suppress the proliferation of uterine stromal cells and elevate the expression of Bax and MMP2 genes. On the contrary, Ido2 inhibitor D-1-MT could enhance the proliferation of stromal cells and expression of Bcl2 gene but decline the Bax/Bcl2 ratio. In the uterine stromal cells, estrogen and progesterone could induce the expression of Ido2 mRNA. These data indicate that Ido2 may be important for mouse embryo implantation and decidualization.

Innate immune system and preeclampsia

Normal pregnancy is considered as a Th2 type immunological state that favors an immune-tolerance environment in order to prevent fetal rejection. Preeclampsia (PE) has been classically described as a Th1/Th2 imbalance; however, the Th1/Th2 paradigm has proven insufficient to fully explain the functional and molecular changes observed during normal/pathological pregnancies. Recent studies have expanded the Th1/Th2 into a Th1/Th2/Th17 and regulatory T-cells paradigm and where dendritic cells could have a crucial role. Recently, some evidence has emerged supporting the idea that mesenchymal stem cells might be part of the feto-maternal tolerance environment. This review will discuss the involvement of the innate immune system in the establishment of a physiological environment that favors pregnancy and possible alterations related to the development of PE.

Differential expression and regulation of Tdo2 during mouse decidualization

Tryptophan 2,3-dioxygenase (Tdo2) is a rate-limiting enzyme which directs the conversion of tryptophan to kynurenine. The aim of this study was to examine the expression and regulation of Tdo2 in mouse uterus during decidualization. Tdo2 mRNA was mainly expressed in the decidua on days 6-8 of pregnancy. By real-time PCR, a high level of Tdo2 expression was observed in the uteri from days 6 to 8 of pregnancy, although Tdo2 expression was observed on days 1-8. Simultaneously, Tdo2 mRNA was also detected under in vivo and in vitro artificial decidualization. Estrogen, progesterone, and 8-bromoadenosine-cAMP could induce the expression of Tdo2 in the ovariectomized mouse uterus and uterine stromal cells. Tdo2 could regulate cell proliferation and stimulate the expression of decidual marker Dtprp in the uterine stromal cells and decidual cells. Overexpression of Tdo2 could upregulate the expression of Ahr, Cox2, and Vegf genes in uterine stromal cells, while Tdo2 inhibitor 680C91 could downregulate the expression of Cox2 and Vegf genes in uterine decidual cells. These data indicate that Tdo2 may play an important role during mouse decidualization and be regulated by estrogen, progesterone, and cAMP.

Thyroid autoantibodies in pregnancy: their role, regulation and clinical relevance

Autoantibodies to thyroglobulin and thyroid peroxidase are common in the euthyroid population and are considered secondary responses and indicative of thyroid inflammation. By contrast, autoantibodies to the TSH receptor are unique to patients with Graves' disease and to some patients with Hashimoto's thyroiditis. Both types of thyroid antibodies are useful clinical markers of autoimmune thyroid disease and are profoundly influenced by the immune suppression of pregnancy and the resulting loss of such suppression in the postpartum period. Here, we review these three types of thyroid antibodies and their antigens and how they relate to pregnancy itself, obstetric and neonatal outcomes, and the postpartum.

Adaptive immune responses during pregnancy

It has long been believed that there is no immune interaction between mother and conceptus during pregnancy. This concept changed after evidence was provided that the maternal immune system is aware of the semiallogeneic conceptus and develops strategies to tolerate it. Since then, finely regulated mechanisms of active tolerance toward the fetus have been described. This Special Issue of the American Journal of Reproductive Immunology deals with these mechanisms. It begins with the description of minor histocompatibility antigens in the placenta; it further goes through adaptive immune responses toward paternal fetal antigens, mostly concentrating on regulatory T cells and molecules modulating the Th1/Th2 balance. The participation of antibody-producing B cells in normal and pathological pregnancies is also discussed. This introductory chapter resumes the concepts presented throughout the Issue and discusses the clinical applications raised from these concepts.

Physiological and molecular determinants of embryo implantation

Embryo implantation involves the intimate interaction between an implantation-competent blastocyst and a receptive uterus, which occurs in a limited time period known as the window of implantation. Emerging evidence shows that defects originating during embryo implantation induce ripple effects with adverse consequences on later gestation events, highlighting the significance of this event for pregnancy success. Although a multitude of cellular events and molecular pathways involved in embryo-uterine crosstalk during implantation have been identified through gene expression studies and genetically engineered mouse models, a comprehensive understanding of the nature of embryo implantation is still missing. This review focuses on recent progress with particular attention to physiological and molecular determinants of blastocyst activation, uterine receptivity, blastocyst attachment and uterine decidualization. A better understanding of underlying mechanisms governing embryo implantation should generate new strategies to rectify implantation failure and improve pregnancy rates in women.

Progesterone-mediated immunomodulation in pregnancy: its relevance to leukocyte immunotherapy of recurrent miscarriage

Progesterone is crucial for the establishment and maintenance of pregnancy. Progesterone-regulated genes in the pregnant uterus control the development of endometrial receptivity as well as recruitment and differentiation of decidual NK cells, which in turn act on angiogenesis and trophoblast invasion. The link between progesterone and the immune system is established by lymphocyte progesterone receptors expressed in peripheral blood gammadelta T cells of pregnant women and in peripheral NK cells. Regulation of lymphocyte progesterone receptors is activation related, thus efficient recognition of fetal antigens is a requirement for the initiation of progesterone-dependent immunoregulatory mechanisms. Several immunological effects of progesterone are mediated by progesterone-induced blocking factor--the product of a progesterone-induced gene in lymphocytes. One part of unexplained recurrent miscarriages might have an immunological etiology. Immunization of the mothers with paternal or third-party leukocytes aims to correct the misregulated antifetal immune response. There are, however, serious concerns about this treatment, including the lack of information about the mode of action and possible adverse effects of the treatment, the failure to detect a significant effect of immunotherapy and the lack of a reliable generally accepted marker for patient selection. These concerns will be discussed in this review.

Coding region polymorphisms in the indoleamine 2,3-dioxygenase (INDO) gene and recurrent spontaneous abortion

Indoleamine 2,3-dioxygenase (INDO) catalyzes degradation of the indole ring of indoleamines and locally depletes tryptophan. INDO expression suppresses T cell proliferation and activation. Genetic variation in the INDO gene may contribute to the variable INDO enzyme expression, activity and severity of some diseases. Recurrent spontaneous abortion (RSA) is a common pregnancy complication and the exact causes of RSA are not yet known. We performed an association study between INDO single nucleotide polymorphisms (SNPs) and RSA. To identify INDO SNPs we sequenced DNA samples for ten exons and adjacent intronic regions from 111 RSA patients. Consequently 10 SNPs were detected; four in exons (one in exon 4, two in exon 9 and one in exon 10) and six in intronic regions (one in intron 3, three in intron 6, one in intron 8 and one in intron 9). Three (IVS3+562 del C, IVS8+116 T→G and IVS9+2431 G→A) of these ten SNPs have been registered at the NCBI SNP database. Statistical analysis of allele, genotype and haplotype frequency distribution in the three most frequent SNPs (IVS3+562 del C, IVS6+61 G→A and IVS9+2431 G→A) showed no significant differences between the 111 RSA and 105 matched control women. CGA and CGG were the most frequent haplotypes in both the RSA and control groups. We conclude that there is no association between INDO polymorphisms and susceptibility of Iranian women to RSA.

Profile of peripheral blood neutrophil cytokines in diabetes type 1 pregnant women and its correlation with selected parameters in the newborns

PROBLEM

Interleukin (IL)-12, IL-10, tumor necrosis factor-alpha (TNF-alpha), IL-6 and IL-8 alter as pregnancy progresses, implying continuous immune regulation associated with the maintenance of pregnancy. We aimed to evaluate the peripheral blood neutrophil-derived production of these cytokines in the course of pregnancy complicated by type 1 diabetes.

METHOD

of study These parameters were measured in samples from healthy non-pregnant (C), diabetic non-pregnant (D), healthy pregnant (P) and pregnant diabetic (PD) women.

RESULTS

Neutrophil-derived secretion of TNF-alpha and IL-12 increased along with progression of pregnancy in PD and P groups. The concentration of IL-10 from lipopolysaccharide (LPS)-stimulated neutrophils increased during the course of uncomplicated pregnancy but decreased in diabetic pregnancy. Concentration of IL-8 decreased with the advancing gestational age in P and PD groups. LPS-stimulated neutrophil-derived IL-6 concentration increased only in PD patients.

CONCLUSION

Our results show that diabetes creates pro-inflammatory environment thus potentially influencing the outcome of pregnancy. We conclude that neutrophil-derived cytokine production could contribute to the complications seen in pregnant women with type 1 diabetes.

Do molecular signals from the conceptus influence endometrium decidualization in rodents?

A critical period in establishing pregnancy occurs after the onset of implantation but before placental development. Evidence strongly suggests that abnormalities occurring during this period can result in pregnancy termination or in pre-eclampsia; the latter may lead to small-for-gestational-weight offspring that are likely to be unhealthy. Clearly, events occurring in the endometrium during the implantation process are crucial for proper fetal development and for optimal offspring health. In several mammalian species bi-directional communication between the conceptus and endometrium during implantation is required for successful pregnancy. Although different implantation and placentation modes occur in different mammalian species, common aspects of this bi-directional signaling may exist. The molecular signals from the trophoblast cells of the conceptus, which direct endometrial changes during implantation progression, are well known in some nonrodent species. Currently, we know little about such signaling in rodents during implantation progression, when the endometrium undergoes decidualization. This review focuses on data that support the hypothesis that paracrine signals from the rodent conceptus influence decidualization. Where possible, these findings are compared and contrasted with information currently known in other species that exhibit different implantation modes.

Potential immunomodulatory role of VIP in the implantation sites of prediabetic nonobese diabetic mice

Among several factors known to modulate embryo implantation and survival, uterine quiescence and neovascularization, maternal immunotolerance through the Th1/Th2 cytokine balance towards a Th2 profile, local regulatory T-cell (Treg) activation, and high levels of progesterone were assigned a prominent role. Vasoactive intestinal peptide (VIP) is a neuroimmunopeptide that has anti-inflammatory effects, promotes Th2 cytokines and CD4+CD25+FOXP3+Treg activation, and stimulates exocrine secretion, smooth muscle relaxation, and vasodilatation favoring uterus quiescence. The goal of the present work was to explore the participation of VIP in the implantation sites of normal and pregnant prediabetic nonobese diabetic (NOD) females, a mouse strain that spontaneously develops an autoimmune exocrinopathy similar to Sjögren's syndrome. Our results indicate a reduction in litter size from the third parturition onwards in the NOD female lifespan with increased resorption rates. Progesterone systemic levels were significantly decreased in pregnant NOD mice compared with BALB/c mice, although the allogeneic response to progesterone by spleen cells was not impaired. VIP receptors,Vipr1andVipr2(Vpac1andVpac2), were expressed at the implantation sites and VIP induced leukemia inhibitory factor (LIF) and Treg marker expression in both strains; however, a reducedVipexpression was found in NOD implantation sites. We conclude that the reduced birth rate at 16-week-old NOD mice with a Th1 systemic cytokine profile involves resorption processes with a lower expression of VIP at the sites of implantation, which acts as a local inducer of pro-implantatory LIF and Treg activation.

CTLA4Ig gene transfer alleviates abortion in mice by expanding CD4+CD25+ regulatory T cells and inducing indoleamine 2,3-dioxygenase

Successful pregnancy requires a state of immunological tolerance since normally the maternal immune system does not reject the semi-allogeneic conceptus. Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4), a ligand for B7, delivers negative signals to antigen presenting cells (APCs) to compete with CD28 for binding to B7 molecules and down-regulate proinflammatory responses, thus inhibiting T cell activation. Using CBA/J x DBA/2 matings as an abortion-prone model, we observed that adenovirus-mediated CTLA4Ig (Ad-CTLA4Ig) gene transfer improves pregnancy outcome. Ad-CTLA4Ig therapy skewed the ability of serum cytokine production toward a Th2 bias. Flow cytometry revealed that Ad-CTLA4Ig administration expanded peripheral CD4(+)CD25(+) regulatory T cell populations in CBA/J x DBA/2 matings. Furthermore, Ad-CTLA4Ig administration induced indoleamine 2,3-dioxygenase (IDO) and Foxp3 mRNA expression at the materno-fetal interface. Our results demonstrate that adenovirus-mediated CTLA4Ig gene transfer improves pregnancy outcome in a murine model of abortion by expanding the CD4(+)CD25(+) regulatory T cell population and inducing IDO mRNA expression.