The role of gamma/delta T cells in the feto-maternal relationship

Assessment of immune cells in the uterine fluid at the time of the embryo transfer

PROBLEM

Although endometrial receptivity is a key factor in influencing implantation in both naturally conceived and assisted reproductive technology (ART) cycles, very little is known about the endometrium milieu around the time of implantation. Previous studies have demonstrated the presence of several cytokines in the endometrium that affect implantation. However, there is lacking data about the presence of immune cell subtypes within the endometrium and in the uterine cavity at the time of implantation.

METHOD OF STUDY

This study was approved by the Institutional Review Board (# 225589). The study was designed as a prospective observational cohort study between May 2021 and December 2022 at a single academic-based fertility center. All patients underwent at least one In Vitro Fertilization (IVF) cycle and have frozen embryos. Twenty-four participants were recruited for this study which was conducted during the frozen embryo transfer (FET) cycle regardless of the outcome of previous cycles. Two samples were acquired from each subject, denoted as lower and upper. A trial transfer catheter was introduced under ultrasound guidance into the lower uterine segment. Upon removal, the tip was rinsed in IMDM medium containing 10% FBS (lower uterus). A transfer catheter was then loaded with the embryo that was placed in the upper uterus under ultrasound guidance. The tip of the transfer catheter was rinsed in separate aliquot of the above media (upper uterus). After centrifugation, pelleted cells were stained for the following surface markers: CD45, CD3, CD19, CD4, CD8, gamma delta TCR, CD25, CD127, CD66b, CD14, CD16, CD56 and acquired on Sony SP6800 Spectral Analyzer.

RESULTS

Upon staining the pelleted cells, we were able to identify viable leukocytes from samples obtained from both, upper and lower uterus (0.125 × 106 cells ± SD 0.32), (0.123 × 106 cells ± SD 0.12), respectively. Among total viable cells, there was no significant difference in both percent and number of CD45+ cells between the upper and lower uterus (9.88% ± 6.98 SD, 13.67% ± 9.79 SD, p = .198) respectively. However, there was significantly higher expression of CD3+ (p = .006), CD19+ (p = .032) and CD14+ (p = .019) cells in samples collected from upper compared to lower uterus. Within all CD3+ cells, we found that gamma delta T cells (GDT) were the major population of T cells in both upper and lower uterus. In contrast, CD8+ T cells were significantly higher in the lower uterus when compared to the upper uterus (p = .009). There was no statistically significant difference in the expression of CD4+ T cells, T regulatory cells (CD4+CD25+CD127-), NK cells (CD56+), neutrophils (CD66b+) and FcγRIII+ cells (CD16+) between upper and lower uterus.

CONCLUSIONS

We believe the immune milieu at the time of embryo transfer will affect implantation. Understanding the composition of immune cells will guide further research in identifying optimal immune milieus that favor implantation. Comprehensive analysis of endometrium is expected to lead to new diagnostic and therapeutic approaches to improve IVF outcomes.

Innate and Adaptive Immune Systems in Physiological and Pathological Pregnancy

The dynamic immunological changes occurring throughout pregnancy are well-orchestrated and important for the success of the pregnancy. One of the key immune adaptations is the maternal immune tolerance towards the semi-allogeneic fetus. In this review, we provide a comprehensive overview of what is known about the innate and adaptive immunological changes in pregnancy and the role(s) of specific immune cells during physiological and pathological pregnancy. Alongside this, we provided details of remaining questions and challenges, as well as future perspectives for this growing field of research. Understanding the immunological changes that occur can inform potential strategies on treatments for the optimal health of the neonate and pregnant individual both during and after pregnancy.

An increased proportion of progesterone receptor A in peripheral B cells from women who ultimately underwent spontaneous preterm birth

The enormous challenge in unraveling the etiology of preterm birth (PTB) is to understand the complex interactions between gestational hormones, the immune system and reproductive tissues. PTB can be divided into spontaneous PTB (sPTB) and medically-indicated PTB, e.g. due to preeclampsia (PE) or HELLP syndrome. Progesterone (P4), important for establishment and maintenance of pregnancy, exerts anti-inflammatory effects. The impact of P4 on B cells and its support of maintaining maternal-fetal tolerance is widely unexplored. Therefore, we aimed to determine whether B cells express the progesterone receptor (PR) and to dissect a possible role of PR+ B cells in PTB. We found enhanced IL-6, IL-21 and TNF-α concentrations in maternal plasma in patients with sPTB and PE/HELLP compared to term delivery (TD), accompanied by enhanced PR-A expression by CD19+ B cells. In a second phase of the study, we recruited patients with imminent PTB (iPTB) and controls. Samples were collected at hospital admission and to a later time point, then divided into iPTB patients who delivered preterm and patients whose PTB was prevented. Within the group of iPTB patients, we observed very clear differences: enhanced levels of pro-inflammatory cytokines and increased percentages of PR-A+CD19+ B cells were found in iPTB patients that delivered preterm compared to patients who did not deliver preterm. We conclude that PTB is associated with the activation of an inflammatory pathway leading to the induction of PR-A by B cells. This might further trigger inflammation, result in the break of maternal-fetal tolerance and induce delivery.

Identification of key genes and immune cell infiltration in recurrent implantation failure: A study based on integrated analysis of multiple microarray studies

PROBLEM

Recurrent implantation failure (RIF) refers to a challenging topic in assisted reproductive technology (ART), the etiology of which may be attributed to impaired endometrial receptivity; however, the precise pathogenesis of RIF has not been thoroughly elucidated.

METHOD OF STUDY

Four RIF microarray datasets were obtained from the Gene Expression Omnibus database and integrated by the "sva" R package. The differentially expressed genes (DEGs) were analyzed using the "limma" package and then GO, KEGG, GSEA, and GSVA were applied to perform functional and pathway enrichment analysis. The immune cell infiltration in the RIF process was evaluated by the CIBERSORT algorithm. Finally, the hub genes were identified through the CytoHubba and subsequently verified using two items of external endometrial data.

RESULTS

236 genes were differentially expressed in the endometrium of the RIF group. Functional enrichment analysis demonstrated that the biological functions of DEGs were mainly correlated to the immune-related pathways, including immune response, TNF signaling pathway, complement and coagulation cascades. Among the immune cells, γδ T cells decreased significantly in the endometrium of RIF patients. In addition, the key DEGs such as PTGS2, FGB, MUC1, SST, VCAM1, MMP7, ERBB4, FOLR1, and C3 were screened and identified as the hub genes involved in the pathogenesis of RIF.

CONCLUSIONS

Abnormal immune response regulation of endometrium contributes to the occurrence of RIF, and γδ T cells may be the pivotal immune cells causing RIF. At the same time, the novel hub genes identified will provide effective targets for the prediction and therapy of RIF.

Sex-biased adaptive immune regulation in cancer development and therapy

The cancer research field is finally starting to unravel the mystery behind why males have a higher incidence and mortality rate than females for nearly all cancer types of the non-reproductive systems. Here, we explain how sex - specifically sex chromosomes and sex hormones - drives differential adaptive immunity across immune-related disease states including cancer, and why males are consequently more predisposed to tumor development. We highlight emerging data on the roles of cell-intrinsic androgen receptors in driving CD8⁺ T cell dysfunction or exhaustion in the tumor microenvironment and summarize ongoing clinical efforts to determine the impact of androgen blockade on cancer immunotherapy. Finally, we outline a framework for future research in cancer biology and immuno-oncology, underscoring the importance of a holistic research approach to understanding the mechanisms of sex dimorphisms in cancer, so sex will be considered as an imperative factor for guiding treatment decisions in the future.

Comparing Mouse and Human Tissue-Resident γδ T Cells

Circulating immune cell compartments have been extensively studied for decades, but limited access to peripheral tissue and cell yield have hampered our understanding of tissue-based immunity, especially in γδ T cells. γδ T cells are a unique subset of T cells that are rare in secondary lymphoid organs, but enriched in many peripheral tissues including the skin, uterus, and other epithelial tissues. In addition to immune surveillance activities, recent reports have revealed exciting new roles for γδ T cells in homeostatic tissue physiology in mice and humans. It is therefore important to investigate to what extent the developmental rules described using mouse models transfer to human γδ T cells. Besides, it will be necessary to understand the differences in the development and biogenesis of human and mouse γδ T cells; to understand how γδ T cells are maintained in physiological and pathological circumstances within different tissues, as well as characterize the progenitors of different tissue-resident γδ T cells. Here, we summarize current knowledge of the γδ T phenotype in various tissues in mice and humans, describing the similarities and differences of tissue-resident γδ T cells in mice and humans.

Early Pregnancy Human Decidua Gamma/Delta T Cells Exhibit Tissue Resident and Specific Functional Characteristics

A successful pregnancy is a complicated process that builds upon two aspects of the maternal immune system that need to be balanced. As one of the indispensable groups of immune cell at the maternal-fetal interface, the decidual gamma/delta (γδ) T cells have attracted research attention in normal pregnancy and miscarriage. However, the role of γδ T cells in fetal growth remains poorly understood. Here we found that the γδ T cell population resident in decidua during early pregnancy was enriched and secreted growth factors including growth differentiation factor 15 (GDF15) and bone morphogenetic protein 1 (BMP1). A diminution in such growth factors may impair fetal development and result in fetal growth restriction. We also observed that early decidual γδ T cells exhibited stronger cytokine-secretion characteristics, but that their cytotoxic actions against A549 cells were weaker, compared with γδ T cells in peripheral blood mononuclear cells (PBMCs). In addition, the functional abilities of early decidual γδ T cells in promoting trophoblast cell proliferation, migration, invasion, and tube formation were also significantly more robust than in γδ T cells of PBMCs. These findings highlight the importance of γδ T cells in fetal growth and maternal immunotolerance during pregnancy, and show that they differ from γδ T cells in PBMCs. We thus recommend additional investigation in this research area to further elucidate a role for γδ T cells in pregnancy.

Progesterone: A Unique Hormone with Immunomodulatory Roles in Pregnancy

Progesterone is well known for its numerous endocrinologic roles in pregnancy but is also endowed with fascinating immunomodulatory capabilities. It can downregulate the induction of inflammatory reactions, the activation of immune cells and the production of cytokines, which are critical mediators of immune responses. These features appear to be critical to the success of pregnancy, given the ability of maternal immune reactivity to interfere with pregnancy and to contribute to several pregnancy complications. This review summarizes the contribution of maternal immune effectors in general, and cytokines in particular, to pregnancy complications such as recurrent miscarriage, pre-eclampsia and preterm labor; it describes the promise offered by supplementation with progesterone and the oral progestogen dydrogesterone, as well as the progesterone-induced blocking factor in the prevention and/or treatment of these serious complications.

Effect of steroid hormone receptor gene variants PROGINS (Alu insertion) and PGR C/T (rs1042839) as a risk factor for recurrent pregnancy loss in Kashmiri population (North India)

AIM

To unveil and evaluate the association and analyze the incidence and pattern of PGR gene polymorphisms (PROGINS insertion and PGR exon 5-C/T polymorphism) in recurrent pregnancy loss (RPL) couples of Kashmir.

METHODS

In this study, analyses of PGR gene polymorphisms in RPL couples were genotyped by amplification-refractory mutation system polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism.

RESULTS

Molecular analysis of PGR gene polymorphisms indicated that the genotypic and allelic frequencies of PROGINS insertion and PGR exon 5 C/T polymorphisms of female group in cases and controls to be significantly different and poses risk in predisposition to RPL. Moreover, haplotype analysis in female group revealed that P1P2/CC and P1P2/CT genotype are significantly associated with RPL.

CONCLUSION

Our data indicate that the PROGINS insertion and exon 5-C/T polymorphism can act as useful genetic markers in the female group, but needs to be replicated in further studies including various other single nucleotide polymorphisms of PGR gene relevant to pregnancy loss which may contribute to novel therapeutic targets with improved conclusions.

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

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

Activated γδ T Cells With Higher CD107a Expression and Inflammatory Potential During Early Pregnancy in Patients With Recurrent Spontaneous Abortion

Previous studies have reported the involvement of γδ T cells in recurrent spontaneous abortion (RSA); however, both pathogenic and protective effects were suggested. To interrogate the role of γδ T cells in RSA, peripheral blood from RSA patients and healthy women with or without pregnancy were analyzed for γδ T cells by flow cytometry (n = 9–11 for each group). Moreover, the decidua from pregnant RSA patients and healthy controls (RSA-P and HC-P group, respectively) was simultaneously stained for γδ T cells by immunohistochemistry (IHC) and bulk sequenced for gene expression. Our results demonstrated that the frequencies of peripheral γδ T cells and their subpopulations in RSA patients were comparable to that in healthy subjects, but the PD1 expression on Vδ2⁺ cells was increased in pregnant patients. Furthermore, peripheral Vδ2⁺ cells in RSA-P patients demonstrated significantly increased expression of CD107a, as compared to that in pregnant healthy controls. In addition, RSA-P patients had higher proportion of IL-17A-secreting but not IL-4-secreting Vδ2⁺ cells compared to the control groups. In decidua, an inflammatory microenvironment was also evident in RSA-P patients, in which CCL8 expression and the infiltration of certain immune cells were higher than that in the HC-P group, as revealed by transcriptional analysis. Finally, although the presence of γδ T cells in decidua could be detected during pregnancy in both RSA patients and healthy subjects by multicolor IHC analysis, the expression of CD107a on γδ T cells was markedly higher in the RSA-P group. Collectively, our results indicated that the increased activation, cytotoxicity, and inflammatory potential of peripheral and/or local γδ T cells might be responsible for the pathogenesis of RSA. These findings could provide a better understanding of the role of γδ T cells in RSA and shed light on novel treatment strategies by targeting γδ T cells for RSA patients.

Roles of γδT cells in pregnancy and pregnancy-related complications

A successful pregnancy is a complex and unique process comprised of discrete events, including embryo implantation, placentation, and parturition. To maintain the balance between maternal-fetal immune tolerance and resistance to infections, the maternal immune system must have a high degree of stage-dependent plasticity throughout the period of pregnancy. Innate immunity is the frontline force for the establishment of early anti-infection and tolerance mechanisms in mammals. Belonging to the innate immune system, a subset of T cells called γδT cells (based on γδT cell receptors) are the main participants in immune surveillance and immune defense. Unlike traditional αβT cells, γδT cells are regarded as a bridge between innate immunity and acquired immunity. In this review, we summarize current knowledge on the functional plasticity of γδT cells during pregnancy. Furthermore, we discuss the roles of γδT cells in pathological pregnancies.

Multiomic immune clockworks of pregnancy

Preterm birth is the leading cause of mortality in children under the age of five worldwide. Despite major efforts, we still lack the ability to accurately predict and effectively prevent preterm birth. While multiple factors contribute to preterm labor, dysregulations of immunological adaptations required for the maintenance of a healthy pregnancy is at its pathophysiological core. Consequently, a precise understanding of these chronologically paced immune adaptations and of the biological pacemakers that synchronize the pregnancy "immune clock" is a critical first step towards identifying deviations that are hallmarks of peterm birth. Here, we will review key elements of the fetal, placental, and maternal pacemakers that program the immune clock of pregnancy. We will then emphasize multiomic studies that enable a more integrated view of pregnancy-related immune adaptations. Such multiomic assessments can strengthen the biological plausibility of immunological findings and increase the power of biological signatures predictive of preterm birth.

γδ T cell frequencies are altered in HIV positive pregnant South African women and are associated with preterm birth

Background

Preterm birth is the leading cause of neonatal and child mortality worldwide. Maternal HIV infection and antiretroviral treatment (ART) increase the rate of preterm birth, but the underlying mechanisms remain unknown, limiting progress in prediction, prevention and treatment. While overall γδ T cell levels remain constant, acute HIV infection is associated with a depletion of the Vδ2 subset and an increase in the Vδ1 subset, which do not return to baseline with ART. γδ T cells have also been implicated in adverse pregnancy outcomes and we therefore investigated the potential association between maternal HIV infection, peripheral γδ T cell frequencies and preterm birth.

Methods

Study participants were HIV positive (n = 47) and HIV negative (n = 45) women enrolled in a prospective pregnancy cohort study at Chris Hani Baragwanath Academic Hospital in Soweto, South Africa. Women were enrolled in early pregnancy and gestational age was accurately determined by first trimester ultrasound scan. Peripheral blood samples were collected in each trimester and peripheral blood mononuclear cells isolated. Frequencies of γδ T cells, Vδ1+ and Vδ2+ γδ T cell subsets, and CCR6 chemokine receptor expression were determined by flow cytometry.

Results

Total γδ T cell levels were similar between HIV positive and HIV negative women throughout pregnancy. However, in each trimester maternal HIV infection was associated with reduced levels of the Vδ2+ subset and increased levels of the Vδ1+ subset, leading to a reversal of the Vδ1/Vδ2 ratio. Timing of ART initiation among HIV positive women did not affect levels of γδ T cells, the Vδ1+ and Vδ2+ subsets, or the Vδ1/Vδ2 ratio. Importantly, preterm birth was associated with lower total γδ T cell levels in early pregnancy and γδ T cell frequencies were lowest in HIV positive women who delivered preterm. Moreover, in the first trimester the proportion of Vδ1+ T cells that were CCR6+ was significantly reduced in HIV+ women and women who delivered preterm, resulting in the lowest proportion of CCR6+ Vδ1 T cells in HIV positive women who delivered preterm.

Conclusions

Our findings suggest that altered γδ T cell frequencies may link maternal HIV infection and preterm birth. γδ T cell frequencies in early pregnancy may serve as predictive biomarkers to identify women at risk of delivering preterm.

Is there a role for HLA-G in the induction of regulatory T cells during the maintenance of a healthy pregnancy?

PROBLEM

Pregnancy remains an immune challenge for the uterus that has to adapt to a semi-allogeneic fetus using various regulatory mechanisms. Both HLA-G and regulatory T cells (CD4⁺  CD25⁺  FOXP3⁺  T_regs ) are upregulated in successful pregnancy, but not in abortion. It is unclear if HLA-G plays a role in the upregulation of regulatory cells.

METHOD OF STUDY

We measured the level of both sHLA-G and T_reg  cells in the blood of healthy pregnant multigravida, unexplained recurrent spontaneous abortions (URSA) and healthy non-pregnant and nulliparous females. We cultured peripheral blood lymphocytes of healthy non-pregnant multigravida females who never had an abortion with lymphocytes of their partners at ratio of 1:1, with and without sHLA-G to detect changes in number of T_reg  cells, or relevant cytokines.

RESULTS

Soluble HLA-G concentrations and T_reg  cells percentage were significantly lower in women with URSA as compared to healthy pregnant multigravida women and were comparable to healthy non-pregnant nulliparous women. Percentage of T_regs  increased between zero time and mixed lymphocyte cultures (MLC) in both cultures with and without recombinant sHLA-G but no significant difference between the two cultures. When stimulated with sHLA-G the mean extracellular IL-10 concentration was unchanged, while the mean INF-γ concentration was slightly higher with no significant difference. Intracellular TGF-β was higher in CD4⁺  cells after incubation with sHLA-G.

CONCLUSION

The results of this study are consistent with previous studies on the role of sHLA-G and T_reg  cells in inducing immune-tolerance in pregnancy. The results also suggest a possible role for HLA-G in the enrichment of T_reg  cells.

Human Peripheral Blood Gamma Delta T Cells: Report on a Series of Healthy Caucasian Portuguese Adults and Comprehensive Review of the Literature

Gamma delta T cells (Tc) are divided according to the type of Vδ and Vγ chains they express, with two major γδ Tc subsets being recognized in humans: Vδ2Vγ9 and Vδ1. Despite many studies in pathological conditions, only a few have quantified the γδ Tc subsets in healthy adults, and a comprehensive review of the factors influencing its representation in the blood is missing. Here we quantified the total γδ Tc and the Vδ2/Vγ9 and Vδ1 Tc subsets in the blood from 30 healthy, Caucasian, Portuguese adults, we characterized their immunophenotype by 8-color flow cytometry, focusing in a few relevant Tc markers (CD3/TCR-γδ, CD5, CD8), and costimulatory (CD28), cytotoxic (CD16) and adhesion (CD56) molecules, and we examined the impacts of age and gender. Additionally, we reviewed the literature on the influences of race/ethnicity, age, gender, special periods of life, past infections, diet, medications and concomitant diseases on γδ Tc and their subsets. Given the multitude of factors influencing the γδ Tc repertoire and immunophenotype and the high variation observed, caution should be taken in interpreting “abnormal” γδ Tc values and repertoire deviations, and the clinical significance of small populations of “phenotypically abnormal” γδ Tc in the blood.

Placental bed research: II. Functional and immunological investigations of the placental bed

Research on the placenta as the interface between the mother and the fetus has been undertaken for some 150 years, and in 2 subsequent reviews, we attempted to summarize the situation. In the first part, we described the discovery of unique physiological modifications of the uteroplacental spiral arteries, enabling them to cope with a major increase in blood flow necessary to ensure proper growth of the fetus. These consist of an invasion of the arterial walls by trophoblast and a progressive disappearance of its normal structure. Researchers then turned to the pathophysiology of the placental bed and in particular to its maternal vascular tree. This yielded vital information for a better understanding of the so-called great obstetrical syndromes (preeclampsia, fetal growth restriction, premature labor and delivery, placenta accreta). Systematic morphological investigations of the uteroplacental vasculature showed that preeclampsia is associated with decreased or failed transformation of spiral arteries and the persistence of endothelial and smooth muscle cells in segments of their myometrial portion. Here we report on recent functional investigations of the placental bed, including in situ biophysical studies of uteroplacental blood flow and vascular resistance, and manipulation of uteroplacental perfusion. These new methodologies have provided a novel way of identifying pregnancies in which remodeling is impaired. In animals it is now possible to manipulate uteroplacental blood flow, leading to an enhancement of fetal growth; this opens the way to trials in abnormal human pregnancies. In this second part, we explored a new, extremely important area of research that deals with the role of specific subsets of leukocytes and macrophages in the placental bed. The human first-trimester decidua is rich in leukocytes called uterine natural killer cells. Both macrophages and uterine natural killer cells increase in number from the secretory endometrium to early pregnancy and play a critical role in mediating the process of spiral artery transformation by inducing initial structural changes. It seems therefore that vascular remodeling of spiral arteries is initiated independently of trophoblast invasion. Dysregulation of the immune system may lead to reproductive failure or pregnancy complications, and in this respect, recent studies have advanced our understanding of the mechanisms regulating immunological tolerance during pregnancy, with several mechanisms being proposed for the development of tolerance to the semiallogeneic fetus. In particular, these include several strategies by which the trophoblast avoids maternal recognition. Finally, an important new dimension is being explored: the likelihood that pregnancy syndromes and impaired uteroplacental vascular remodeling may be linked to future maternal and even the child's cardiovascular disease risk. The functional evidence underlying these observations will be discussed.

Decidual RANKL/RANK interaction promotes the residence and polarization of TGF-β1-producing regulatory γδ T cells

ABSTACT

Decidual γδΤ (dγδΤ) cells play an essential role during successful pregnancy; however, the residence and polarization of γδΤ cells in decidua remain unclear. In this study, we observed higher levels of receptor activator for nuclear factor-κ B ligand (RANKL) on decidual stromal cells (DSCs), and its receptor RANK on dγδΤ cells in decidua from normal pregnancy compared with patients with recurrent spontaneous abortion (RSA). RANKL expressed by DSCs can induce the polarization of peripheral blood γδΤ (pγδΤ) and dγδΤ cells to Foxp3 + γδΤ cells, and upregulate the expression of transforming growth factor (TGF)-β1. This process is mediated through activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). In addition, RANKL promotes the adhesion of dγδΤ cells to DSCs in vitro, which is associated with the upregulation of ICAM-1 and VCAM-1 on DSCs and integrins on dγδΤ cells. RANKL knockout leads to the decreased numbers of uterus total γδΤ cells, Foxp3+γδΤ cells and the expression of TGF-β1, and the increased pregnancy loss in mice. These results suggest that RANKL is a pivotal regulator of maternal-fetal tolerance by triggering the polarization and residence of TGF-β1-producing Foxp3+γδΤ cells in early pregnancy. The abnormal low level of RANKL/RANK results in pregnancy loss because of the dialogue disorder between DSCs and dγδΤ cells. This observation provides a scientific basis on which a potential marker can be detected to early warning of pregnancy loss.

Progesterone modulates the T-cell response via glucocorticoid receptor-dependent pathways

PROBLEM

Steroid hormones such as progesterone and glucocorticoids rise during pregnancy and are accountable for the adaptation of the maternal immune system to pregnancy. How steroid hormones induce fetal tolerance is not fully understood. We hypothesized that steroid hormones selectively regulate the T-cell response by promoting T-cell death.

METHOD OF STUDY

We incubated murine spleen cells isolated from non-pregnant and pregnant mice with physiological concentrations of steroid hormones in vitro and analyzed T-cell subsets after 48 h of incubation. Results We found that progesterone and the synthetic glucocorticoid dexamethasone induce T-cell death. CD4⁺ regulatory T (T_reg ) cells were refractory toward progesterone-induced cell death, in contrast to conventional CD4⁺ T cells, which resulted in a preferential enrichment of CD4⁺ T_reg cells in culture. T cells isolated from pregnant mice at early and late gestation showed comparable sensitivity to steroid-induced cell death. The target receptor for progesterone in immune cells is controversially discussed. We provide here support of progesterone binding to the glucocorticoid receptor as only T cells lacking the glucocorticoid but not the progesterone receptor showed resistance against progesterone-induced death. Conclusions Our results indicate that high levels of progesterone during pregnancy can induce selective T-cell death by binding the glucocorticoid receptor. Although physiological hormone concentrations were used, due to different bioavailability of steroid hormones in vivo these results have to be validated in an in vivo model. This mechanism might ensure immunological tolerance at the feto-maternal interface at gestation.

IL-25 promotes Th2 bias by upregulating IL-4 and IL-10 expression of decidual γδT cells in early pregnancy

Decidual immune cells (DICs), consisting of both innate and adaptive immune cells, have a pivotal role in maintaining immune tolerance for normal pregnancy. Our previous study demonstrated that interleukin (IL)-25 stimulates the proliferation of decidual stromal cells (DSCs) in an autocrine manner. However, the role of IL-25 in functional regulation of DICs is largely unknown. Flow cytometry was used to analyze the expression of IL-25 and its receptor (IL-17RB) in DICs, and the effect of IL-25 on the expression of Ki-67, IL-4, IL-10, interferon (IFN)-γ and transforming growth factor (TGF)-β in decidual γδT cells. In addition, ELISA assays were performed to detect the secretion of IL-10 and TGF-β in decidual γδT cells. The present findings indicated that decidual CD56 bright CD16-natural killer (NK) cells, natural killer T (NKT) cells, regulatory T (Treg) cells, CD3⁺ T cells, macrophages and γδT cells co-expressed IL-25 and IL-17RB, particularly γδT cells. Recombinant human (rh) IL-25 protein upregulated the expression of Ki-67, IL-4, and IL-10, but downregulated the expression of IFN-γ in γδT cells; however, anti-human IL-25 or IL-17RB neutralizing antibody reversed these effects. These data suggest that IL-25 may promote IL-10 production by γδT cells as well as the proliferation of γδT cells, and possibly forms a positive feedback loop to maintain a T helper 2 cell bias at the maternal-fetal interface and further contributes to the maintenance of successful pregnancy.

Human Zika infection induces a reduction of IFN-γ producing CD4 T-cells and a parallel expansion of effector Vδ2 T-cells

The definition of the immunological response to Zika (ZIKV) infection in humans represents a key issue to identify protective profile useful for vaccine development and for pathogenesis studies. No data are available on the cellular immune response in the acute phase of human ZIKV infection, and its role in the protection and/or pathogenesis needs to be clarified. We studied and compared the phenotype and functionality of T-cells in patients with acute ZIKV and Dengue viral (DENV) infections. A significant activation of T-cells was observed during both ZIKV and DENV infections. ZIKV infection was characterized by a CD4 T cell differentiation toward effector cells and by a lower frequency of IFN-γ producing CD4 T cells. Moreover, a substantial expansion of CD3⁺CD4⁻CD8⁻ T-cell subset expressing Vδ2 TCR was specifically observed in ZIKV patients. Vδ2 T cells presented a terminally differentiated profile, expressed granzyme B and maintained their ability to produce IFN-γ. These findings provide new knowledge on the immune response profile during self-limited infection that may help in vaccine efficacy definition, and in identifying possible immuno-pathogenetic mechanisms of severe infection.

Immunogenetic contributions to recurrent pregnancy loss

While sporadic pregnancy loss is common, occurring in 15 % of pregnancies, recurrent pregnancy loss (RPL) impacts approximately 5 % of couples. Though multiple causes are known (including structural, hormonal, infectious, autoimmune, and thrombophilic causes), after evaluation, roughly half of all cases remain unexplained. The idiopathic RPL cases pose a challenging therapeutic dilemma in addition to incurring much physical and emotional morbidity. Immunogenetic causes have been postulated to contribute to these cases of RPL. Natural Killer cell, T cell expression pattern changes in the endometrium have both been shown in patients with RPL. Human leukocyte antigen (HLA) and cytokine allelic variations have also been studied as etiologies for RPL. Some of the results have been promising, however the studies are small and have not yet put forth outcomes that would change our current diagnosis and management of RPL. Larger database studies are needed with stricter control criteria before reasonable conclusions can be drawn.

A shift in the balance of T17 and Treg cells in menstrual blood of women with unexplained recurrent spontaneous abortion

To determine usefulness of menstrual blood for assessment of differential frequency of T cell subsets, peripheral blood (PB) and menstrual blood (MB) from healthy fertile (n=15), unexplained recurrent spontaneous abortion (URSA) women (n=15) and unexplained infertile women (n=8) were collected in the second day of menstrual bleeding. Frequency of T cell subsets was measured by flow cytometry. URSA and unexplained infertile patients had higher frequency of TCRαβ(+)CD3(+)CD56(-) and CD45RO(+) T cells as well as CD45RO(+)/CD45RO(-) ratio in PB as compared to MB. Frequency of CD3(+)TCRγδ(+) cells in PB of unexplained infertile and MB of URSA patients were significantly lower than that in fertile group. In all groups MB contained higher percentage of CD4(+)CD25(+)Foxp3(+) regulatory and lower percentages of CD16(+) T cells compared to PB. T17 cells (CD3(+)CD56(-)IL-17(+)) was found to be significantly higher in MB of only fertile and unexplained infertile subjects and not URSA patients in comparison with PB. Compared to PB, only fertile women had higher T17:Treg ratio in their MB. URSA women had significantly lower MB T17 cells and T17:Treg ratio compared to those in fertile and unexplained infertile women. Based on the findings presented here, we speculate that MB has its own unique immune milieu which is not solely continuation of the immune environment of secretory endometrium. Indeed, immunophenotyping of MB immune cells could potentially be a useful tool for investigation of immunological disturbances in pregnancy-related disorders.

Loss of Intra-Epithelial Endocervical Gamma Delta (GD) 1 T Cells in HIV-Infected Women

PROBLEM

Human gamma delta (GD) T cells play a well-documented role in epithelial barrier surveillance and protection. Two subsets of GD T cells, defined by the use of either the Vdelta2 (GD2) or Vdelta1 (GD1) TCR, predominate. We hypothesized that endocervical GD T cells play important role in lower genital tract anti-HIV immune responses.

METHOD OF STUDY

HIV-infected (n = 18) and HIV-uninfected (n = 19) pre-menopausal women participating in the WIHS cohort were recruited. Frequency and phenotype of GD T cells were determined in endocervical cytobrush samples and peripheral blood by multicolor flow cytometry.

RESULTS

We found depletion of GD2 cells in the blood of HIV-infected women as well as significant decrease in the frequency of endocervical GD1 cells compared to uninfected women.

CONCLUSION

We report for the first time, the GD1 cells are a predominant endocervical T-cell subset that is significantly decreased in HIV-infected women.

MTHFR (C677T) polymorphism and PR (PROGINS) mutation as genetic factors for preterm delivery, fetal death and low birth weight: A Northeast Indian population based study

Preterm delivery (PTD) is one of the most significant contributors to neonatal mortality, morbidity, and long-term adverse consequences for health; with highest prevalence reported from India. The incidence of PTD is alarmingly very high in Northeast India. The objective of the present study is to evaluate the associative role of MTHFR gene polymorphism and progesterone receptor (PR) gene mutation (PROGINS) in susceptibility to PTD, negative pregnancy outcome and low birth weights (LBW) in Northeast Indian population.

Methods

A total of 209 PTD cases {extreme preterm (< 28 weeks of gestation, n = 22), very preterm (28–32 weeks of gestation, n = 43) and moderate preterm (32–37 weeks of gestation, n = 144) and 194 term delivery cases were studied for MTHFR C677T polymorphism and PR (PROGINS) gene mutation. Statistical analysis was performed using SPSS software.

Results

Distribution of MTHFR and PR mutation was higher in PTD cases. Presence of MTHFR C677T polymorphism was significantly associated and resulted in the increased risk of PTD (p < 0.001), negative pregnancy outcome (p < 0.001) and LBW (p = 0.001); more significantly in extreme and very preterm cases. Presence of PR mutation (PROGINS) also resulted in increased risk of PTD and negative pregnancy outcome; but importantly was found to increase the risk of LBW significantly in case of very preterm (p < 0.001) and moderately preterm (p < 0.001) delivery cases.

Conclusions

Both MTHFR C677T polymorphism and PR (PROGINS) mutation are evident genetic risk factors associated with the susceptibility of PTD, negative pregnancy outcome and LBW. MTHFR C677T may be used as a prognostic marker to stratify subpopulation of pregnancy cases predisposed to PTD; thereby controlling the risks associated with PTD.

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This is the first study involving the analysis of genetic risk factors associated with preterm delivery in Northeast India.

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MTHFR C677T polymorphism and PR (PROGINS) mutation in predisposition to preterm delivery, negative pregnancy outcome and low birth weight.

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MTHFR C677T polymorphism may be used as a prognostic marker to stratify subpopulation of pregnancy cases predisposed to PTD; thereby controlling the risks associated with PTD.

Glucocorticoid Regulation of Reproduction

It is well accepted that stress, measured by increased glucocorticoid secretion, leads to profound reproductive dysfunction. In times of stress, glucocorticoids activate many parts of the fight or flight response, mobilizing energy and enhancing survival, while inhibiting metabolic processes that are not necessary for survival in the moment. This includes reproduction, an energetically costly procedure that is very finely regulated. In the short term, this is meant to be beneficial, so that the organism does not waste precious energy needed for survival. However, long-term inhibition can lead to persistent reproductive dysfunction, even if no longer stressed. This response is mediated by the increased levels of circulating glucocorticoids, which orchestrate complex inhibition of the entire reproductive axis. Stress and glucocorticoids exhibits both central and peripheral inhibition of the reproductive hormonal axis. While this has long been recognized as an issue, understanding the complex signaling mechanism behind this inhibition remains somewhat of a mystery. What makes this especially difficult is attempting to differentiate the many parts of both of these hormonal axes, and new neuropeptide discoveries in the last decade in the reproductive field have added even more complexity to an already complicated system. Glucocorticoids (GCs) and other hormones within the hypothalamic-pituitary-adrenal (HPA) axis (as well as contributors in the sympathetic system) can modulate the hypothalamic-pituitary-gonadal (HPG) axis at all levels-GCs can inhibit release of GnRH from the hypothalamus, inhibit gonadotropin synthesis and release in the pituitary, and inhibit testosterone synthesis and release from the gonads, while also influencing gametogenesis and sexual behavior. This chapter is not an exhaustive review of all the known literature, however is aimed at giving a brief look at both the central and peripheral effects of glucocorticoids on the reproductive function.

Expression of kisspeptin/GPR54 and PIBF/PR in the first trimester trophoblast and decidua of women with recurrent spontaneous abortion

Kisspeptin and its receptor GPR54 play a major role in trophoblast invasion, and progesterone-induced blocking factor (PIBF) is needed for maintaining pregnancy. The expression of kisspeptin/GPR54 and PIBF/progesterone receptor (PR) in trophoblasts and deciduas and the relationship between kisspeptin and PIBF were investigated in the same women with recurrent spontaneous abortion (RSA). Trophoblastic and decidual tissues were collected from 32 RSA women who miscarried a genetically normal fetus, and 35 women who had voluntary abortion. Kisspeptin, GPR54, PIBF and PR were investigated using immunohistochemistry. Kisspeptin, GPR54 and PIBF expressions in syncytiotrophoblasts and cytotrophoblasts were decreased in RSA women as compared to controls (P<0.05). Kisspeptin, PIBF and PR expressions in deciduas were significantly decreased in RSA women as compared to controls (P<0.01). GPR54 expression in deciduas nearly showed no difference between the RSA group and the control group (P=0.958). Kisspeptin and PIBF expressions in syncytiotrophoblasts, cytotrophoblasts and deciduas were correlated with each other in the RSA group (Kappa=0.602, P=0.001; Kappa=0.590, P=0.001; Kappa=0.392, P=0.011). These data support the hypothesis that decreased kisspeptin and PIBF expressions in trophoblasts and deciduas are associated with RSA.

Effect of progesterone on Th1/Th2/Th17 and regulatory T cell-related genes in peripheral blood mononuclear cells during pregnancy in cows

T helper (Th) cells play a central role in immune responses and new Th1/Th2/Th17 and regulatory T (Treg)-cell paradigm in pregnancy has developed. Progesterone (P(4)) is essential for the maintenance of pregnancy; however the effect of P(4) on Th1/Th2/Th17 and Treg paradigm is unclear in cows. We evaluated the effect of P(4) on the expression of Th1/Th2/Th17 and Treg-related cytokines, transcription factors, and P(4) receptors in the peripheral blood mononuclear cells (PBMCs) from 8 pregnant (163.1 ± 16.9 days of gestation) and 8 non-pregnant luteal phase cows. PBMCs were stimulated with P(4) at 0, 0.1, 1 or 10 μg/ml, and the mRNA expression of Th1, Th2, Th17 and Treg-related cytokines (IFN-γ, IL-4, IL-17 and TGF-β), transcription factors (T-bet, GATA-3, RORC and Foxp3) and P(4) receptors (PGR, PGRMC1 and PGRMC2) were analyzed by real time RT-PCR. In both pregnant and non-pregnant cows, P(4) significantly inhibited the expression of IFN-γ and IL-17 dose-dependently, whereas P(4) did not affect the expression of TGF-β and Foxp3. In addition, P(4) significantly decreased the expression of T-bet and RORC, and enhanced the expression of IL-4 in the pregnant cows, but this reaction was not found in the non-pregnant cows. P(4) tended to increase PGRMC1 in the pregnant cows but not in the non-pregnant cows, indicating that PGRMC1 may be involved in the regulation of the effect of P(4) during bovine pregnancy. These results indicate that P(4) is an important regulator of Th1/Th2/Th17 and Treg immunity, and higher Th2 immunity is characteristic in the pregnant cows.

Effects of lactation and pregnancy on gene expression of endometrium of Holstein cows at day 17 of the estrous cycle or pregnancy

Objectives were to determine effects of lactation and pregnancy on endometrial gene expression on d 17 of the estrous cycle and pregnancy. Heifers (n = 33) were assigned randomly after parturition to lactating (L, n = 17) or nonlactating (NL, n = 16) groups. Cows were subjected to an ovulation synchronization program for a timed artificial insemination (TAI); 10 cows in L and 12 in NL were inseminated. Slaughter occurred 17 d after the day equivalent to TAI, and intercaruncular endometrial tissues were collected. Gene expression was determined by DNA microarray analysis for pregnant (L, n = 8; NL, n = 6) and noninseminated cyclic (L, n = 7; NL, n = 4) cows. Differentially expressed genes were selected with a P-value <0.01 and absolute expression >40. In addition, a fold effect >1.5 was used as a criterion for genes affected by pregnancy. In total, 210 genes were differentially regulated by lactation (136 downregulated and 74 upregulated), and 702 genes were differentially regulated by pregnancy (407 downregulated and 295 upregulated). The interaction effect of pregnancy and lactation affected 61 genes. Genes up- and downregulated in pregnant cows were associated with several gene ontology terms, such as defense response and interferon regulatory factor, cell adhesion, and extracellular matrix. The gene ontology analyses of up- and downregulated genes of lactating cows revealed terms related to immunoglobulin-like fold, immune response, COMM domain, and non-membrane-bounded organelle. Several genes upregulated by lactation, such as IGHG1, IGLL1, IGK, and TRD, were related to immune function, particularly for B cells and γδ T cells. Developmental genes related to limb and neural development and glucose homeostasis (e.g., DKK1, RELN, PDK4) were downregulated by lactation, whereas an interaction was also detected for RELN. The stated genes associated with immune function and developmental genes expressed in the endometrium affected by lactational state are possible candidate genes for interventions to improve fertility of lactating dairy cows.

Differential expression of CXC chemokines CXCL10 and CXCL12 in term and pre-term neonates and their mothers

BACKGROUND AND AIM

Pre-term delivery is a mostly unknown frequent disorder worldwide. This project aimed to investigate the circulating levels of CXCL12 (SDF-1) and CXCL10 (IP-10) in cord blood of term and pre-term delivered fetuses and their corresponding mothers.

MATERIAL AND METHODS

Cord and peripheral blood samples were collected from 50 pre-term and 50 term infants and their mothers. Serum levels of CXCL12 and CXCL10 were measured by ELISA.

RESULTS

The findings of this study indicated that the circulating levels of CXCL10 were elevated in mothers bearing pre-term infants, while CXCL12 was only increased in pre-term infants.

CONCLUSION

The results suggested that the pathophysiological status of both mother and infant are involved in prematurity. Moreover, these findings suggest an inflammatory response in pre-term labor, which probably is controlled by inducible chemokines such as CXCL10.

Hepatosplenic gamma-delta T-cell lymphoma in a female patient after delivery

Hepatosplenic γδ T-cell lymphoma (HSTCL) is a very rare peripheral T-cell lymphoma characterized by extranodal infiltration of mature malignant post-thymic T-lymphocytes into sinusoids of the liver and spleen without lymphadenopathy and significant cytopenias. The aetiology of the disease is unknown. We describe the case of a female patient in whom HSTCL developed after delivery and who was previously without disease. Flow cytometry and liver puncture are essential for diagnosing HSTCL, especially in patients with unexplained pancytopenia and hepatosplenomegaly. Since phenotypic results can easily be misinterpreted as non-malignant, the examiner should have enough experience to recognize clonal changes of T-lymphocytes. Namely, in contrast to B-lymphocytes, T-lymphocytes do not have an efficient indicator of clonality and are recognized by flow cytometry based only on aberrant expression of commonly present antigens of T-cell and NK-cell subsets. At present, there is no known cure for HSTCL with a maximum survival up to 2 years.

Impact of mouse pregnancy on thymic T lymphocyte subsets

It has been reported that fetal lymphoid progenitor cells are acquired during gestation and are able to develop in the maternal mouse thymus into functional T cells. Moreover, previous pregnancies increase the number of fetal cells in the mother. In the present study, we investigated whether mouse pregnancy induces changes in T lymphocyte subsets in the maternal thymus. We determined the T lymphocyte subsets in two allogeneic cross-breedings, namely CBA/J × BALB/c (normal) and CBA/J × DBA/2 (abortion prone), and investigated the effects of the age and parity of the female, as well as pregnancy outcome, on thymocyte populations. In addition, hormonal effects were evaluated in a syngeneic combination (CBA/J × CBA/J). We found that during pregnancy both hormonal and allogeneic stimuli induced a reduction in the CD4+CD8+ subset with an increase in the CD4+CD8– population. Only young females of the normal combination exhibited an increase in the CD4–CD8+ population. All young mice showed an increase in CD4+CD25+FoxP3+ T cells. Interestingly, the γδT thymus pool was increased in all females of the normal allogeneic pregnancy only, suggesting the participation of this pool in the observed beneficial effect of multiparity in this cross-breeding. Our results demonstrate that allogeneic pregnancies induce important variations in maternal thymocyte subpopulations depending on the age of the female and the male component of the cross-breeding.

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.

Innate immune function in placenta and cord blood of hepatitis C--seropositive mother-infant dyads

Vertical transmission accounts for the majority of pediatric cases of hepatitis C viral (HCV) infection. In contrast to the adult population who develop persistent viremia in approximately 80% of cases following exposure, the rate of mother-to-child transmission (2-6%) is strikingly low. Protection from vertical transmission likely requires the coordination of multiple components of the immune system. Placenta and decidua provide a direct connection between mother and infant. We hypothesized that innate immune responses would differ across the three compartments (decidua, placenta and cord blood) and that hepatitis C exposure would modify innate immunity in these tissues. The study was comprised of HCV-infected and healthy control mother and infant pairs from whom cord blood, placenta and decidua were collected with isolation of mononuclear cells. Multiparameter flow cytometry was performed to assess the phenotype, intracellular cytokine production and cytotoxicity of the cells. In keeping with a model where the maternal-fetal interface provides antiviral protection, we found a gradient in proportional frequencies of NKT and gammadelta-T cells being higher in placenta than cord blood. Cytotoxicity of NK and NKT cells was enhanced in placenta and placental NKT cytotoxicity was further increased by HCV infection. HCV exposure had multiple effects on innate cells including a decrease in activation markers (CD69, TRAIL and NKp44) on NK cells and a decrease in plasmacytoid dendritic cells in both placenta and cord blood of exposed infants. In summary, the placenta represents an active innate immunological organ that provides antiviral protection against HCV transmission in the majority of cases; the increased incidence in preterm labor previously described in HCV-seropositive mothers may be related to enhanced cytotoxicity of NKT cells.

Innate immune function in placenta and cord blood of hepatitis C--seropositive mother-infant dyads

Vertical transmission accounts for the majority of pediatric cases of hepatitis C viral (HCV) infection. In contrast to the adult population who develop persistent viremia in ∼80% of cases following exposure, the rate of mother-to-child transmission (2–6%) is strikingly low. Protection from vertical transmission likely requires the coordination of multiple components of the immune system. Placenta and decidua provide a direct connection between mother and infant. We hypothesized that innate immune responses would differ across the three compartments (decidua, placenta and cord blood) and that hepatitis C exposure would modify innate immunity in these tissues. The study was comprised of HCV-infected and healthy control mother and infant pairs from whom cord blood, placenta and decidua were collected with isolation of mononuclear cells. Multiparameter flow cytometry was performed to assess the phenotype, intracellular cytokine production and cytotoxicity of the cells. In keeping with a model where the maternal-fetal interface provides antiviral protection, we found a gradient in proportional frequencies of NKT and γδ-T cells being higher in placenta than cord blood. Cytotoxicity of NK and NKT cells was enhanced in placenta and placental NKT cytotoxicity was further increased by HCV infection. HCV exposure had multiple effects on innate cells including a decrease in activation markers (CD69, TRAIL and NKp44) on NK cells and a decrease in plasmacytoid dendritic cells in both placenta and cord blood of exposed infants. In summary, the placenta represents an active innate immunological organ that provides antiviral protection against HCV transmission in the majority of cases; the increased incidence in preterm labor previously described in HCV-seropositive mothers may be related to enhanced cytotoxicity of NKT cells.

Innate immune function in placenta and cord blood of hepatitis C--seropositive mother-infant dyads

Vertical transmission accounts for the majority of pediatric cases of hepatitis C viral (HCV) infection. In contrast to the adult population who develop persistent viremia in approximately 80% of cases following exposure, the rate of mother-to-child transmission (2-6%) is strikingly low. Protection from vertical transmission likely requires the coordination of multiple components of the immune system. Placenta and decidua provide a direct connection between mother and infant. We hypothesized that innate immune responses would differ across the three compartments (decidua, placenta and cord blood) and that hepatitis C exposure would modify innate immunity in these tissues. The study was comprised of HCV-infected and healthy control mother and infant pairs from whom cord blood, placenta and decidua were collected with isolation of mononuclear cells. Multiparameter flow cytometry was performed to assess the phenotype, intracellular cytokine production and cytotoxicity of the cells. In keeping with a model where the maternal-fetal interface provides antiviral protection, we found a gradient in proportional frequencies of NKT and gammadelta-T cells being higher in placenta than cord blood. Cytotoxicity of NK and NKT cells was enhanced in placenta and placental NKT cytotoxicity was further increased by HCV infection. HCV exposure had multiple effects on innate cells including a decrease in activation markers (CD69, TRAIL and NKp44) on NK cells and a decrease in plasmacytoid dendritic cells in both placenta and cord blood of exposed infants. In summary, the placenta represents an active innate immunological organ that provides antiviral protection against HCV transmission in the majority of cases; the increased incidence in preterm labor previously described in HCV-seropositive mothers may be related to enhanced cytotoxicity of NKT cells.

Immune cells and molecules in pregnancy: friends or foes to the fetus?

Considering allograft rejection as a basic feature of the immune system, the mammalian pregnancy is an immunological paradox where the semi-allogeneic fetus is not rejected. How are the demands of pregnancy solved in the context of maternal immunity? Medawar's original proposal of maternal immune inertness during pregnancy should be revised to active materno-placental tolerance. Multiple mechanisms are involved in peripheral and local tolerance induction that prevents fetal rejection while maintaining competent immune surveillance and protection. The goal of this review is to discuss the major cellular and molecular components of the immune system that control and promote fetal survival.

Circulating heat shock protein 70 (HSPA1A) in normal and pathological pregnancies

Heat shock proteins (Hsps) are ubiquitous and phylogenetically conserved molecules. They are usually considered to be intracellular proteins with molecular chaperone and cytoprotective functions. However, Hsp70 (HSPA1A) is present in the peripheral circulation of healthy nonpregnant and pregnant individuals. In normal pregnancy, circulating Hsp70 levels are decreased, and show a positive correlation with gestational age and an inverse correlation with maternal age. The capacity of extracellular Hsp70 to elicit innate and adaptive proinflammatory (Th1-type) immune responses might be harmful in pregnancy and may lead to the maternal immune rejection of the fetus. Decreased circulating Hsp70 level, consequently, may promote the maintenance of immunological tolerance to the fetus. Indeed, elevated circulating Hsp70 concentrations are associated with an increased risk of several pregnancy complications. Elevated Hsp70 levels in healthy pregnant women at term might also have an effect on the onset of labor. In preeclampsia, serum Hsp70 levels are increased, and reflect systemic inflammation, oxidative stress and hepatocellular injury. Furthermore, serum Hsp70 levels are significantly higher in patients with the syndrome of hemolysis, elevated liver enzymes, and low platelet count (HELLP syndrome) than in severely preeclamptic patients without HELLP syndrome. In HELLP syndrome, elevated serum Hsp70 level indicates tissue damage (hemolysis and hepatocellular injury) and disease severity. Increased circulating Hsp70 level may not only be a marker of these conditions, but might also play a role in their pathogenesis. Extracellular Hsp70 derived from stressed and damaged, necrotic cells can elicit a proinflammatory (Th1) immune response, which might be involved in the development of the maternal systemic inflammatory response and resultant endothelial damage in preeclampsia and HELLP syndrome. Circulating Hsp70 level is also elevated in preterm delivery high-risk patients, particularly in treatment-resistant cases, and may be a useful marker for evaluating the curative effects of treatment for preterm delivery. In addition, increased circulating Hsp70 levels observed in asthmatic pregnant patients might play a connecting role in the pathomechanism of asthmatic inflammation and obstetrical/perinatal complications. Nevertheless, a prospective study should be undertaken to determine whether elevated serum Hsp70 level precedes the development of any pregnancy complication, and thus can help to predict adverse maternal or perinatal pregnancy outcome. Moreover, the role of circulating Hsp70 in normal and pathological pregnancies is not fully known, and further studies are warranted to address this important issue.

Role of progesterone receptor polymorphisms in the recurrent spontaneous abortions: Indian case

Background

We attempt to ascertain if the 3 linked single nucleotide polymorphisms (SNPs) of the Progesterone Receptor (PR) gene (exon 1: G 1031 C; S344T, exon 4: G 1978 T; L660V and exon 5: C 2310 T; H770H) and the PROGINS insertion in the intron G, between exons 7 and 8, are associated with Recurrent Spontaneous Abortion (RSA) in the Indian population.

Methodology/Principal Findings

A total of 143 women with RSA and 150 controls were sequenced for all the 8 exons looking for the above 3 linked SNPs of the PR gene earlier implicated in the RSA, as well as for any new SNPs that may be possibly found in the Indian population. PROGINS insertion was screened by electrophoresis. We did not find any new mutations, not observed earlier, in our population. Further, we did not find significant role of the *2 allele (representing the mutant allele at the three SNP loci) or the T2 allele (PROGINS insertion) in the manifestation of RSA. We also did not find an LD pattern between each of the 3 SNPs and the PROGINS insertion.

Conclusions/Significance

The results suggest that the PR gene mutations may not play any exclusive role in the manifestation of RSA, and instead, given significantly higher frequency of the *2 allele among the normal women, we surmise if it does not really confer a protective role among the Indian populations, albeit further studies are required in the heterogeneous populations of this region before making any conclusive statement.

Assay of T- and NK-cell subsets and the expression of NKG2A and NKG2D in patients with new-onset systemic lupus erythematosus

This study aims to explore the percentage of T-cell and NK-cell subsets, the expression of NKG2A and NKG2D on CD3+ T cells and CD3-CD56+ NK cells on the total lymphocytes in new-onset systemic lupus erythematosus (SLE) patients, and explore clinical significance of these cell subsets. Thirty-two SLE patients and 32 normal controls were enrolled. Flow cytometry was used to count T- and NK-cell subsets and to detect the expression of NKG2A and NKG2D on CD3+ T cells and CD3-CD56+ NK cells in patients with new-onset SLE. Results show that CD4+ T (t = 2.04, P < 0.05), CD4+/CD8+ T cell (t = 2.66, P < 0.05), CD4+ CD25+ T (t = 2.48, P < 0.05), CD3+CD56+ natural killer T (NKT) (t = 40.05, P < 0.01), CD3-CD56+CD16+ NK-cell subsets (t = 3.50, P < 0.01) were significantly decreased, CD8+ T-cell subsets was significantly increased in patients with new-onset SLE (t = 3.80, P < 0.01), as compared with healthy controls. CD8+ T-cell subset was significantly increased in patients with vasculitis (t = 2.47, P < 0.05), and CD3-CD56+CD16+ NK was increased in patients with arthritis (t = 3.21, P < 0.01). However, no statistically significant correlation was found among different PBMC subsets and SLEDAI activity scores. Patients with SLE had a lower expression of NKG2A (U = 2.42, P < 0.05) as well as NKG2A/NKG2D ratio (t = 2.61, P < 0.05) and a higher expression of NKG2D (t = 2.21, P < 0.05) on CD3+ T cells, compared with normal controls. However, they had a higher expression of NKG2A (t = 2.59, P < 0.05) as well as NKG2A/NKG2D ratio (t = 49.45, P < 0.01) and a lower expression of NKG2D (t = 3.05, P < 0.01) on CD3-CD56+ NK cells. Taken together, the findings indicate the decreased CD4+ T-cell, CD4+/CD8+ T-cell, CD4+CD25+ T-cell, CD3+CD56+ NKT-, and CD3-CD56+CD16+ NK-cell subsets, increased CD8+ T-cell subsets as well as the abnormal expression of NKG2A and NKG2D on CD3+ T and CD3-CD56 + NK cells may play a role in the etiology of SLE.

Progesterone in pregnancy; receptor-ligand interaction and signaling pathways

Progesterone is indispensable in creating a suitable endometrial environment for implantation, and also for the maintenance of pregnancy. Successful pregnancy depends on an appropriate maternal immune response to the fetus. Along with its endocrine effects, progesterone also acts as an "immunosteroid", by contributing to the establishment of a pregnancy protective immune milieu. Progesterone plays a role in uterine homing of NK cells and upregulates HLA-G gene expression, the ligand for NK inhibitory and activating receptors. At high concentrations, progesterone is a potent inducer of Th2-type cytokines as well as of LIF and M-CSF production by T cells. A protein called progesterone-induced blocking factor (PIBF), by inducing a Th2-dominant cytokine production mediates the immunological effects of progesterone. PIBF binds to a novel type of the IL-4 receptor and signals via the Jak/STAT pathway, to induce a number of genes, that not only affect the immune response, but might also play a role in trophoblast invasiveness.