Pregnancy: tolerance and suppression of immune responses

Influence of forkhead box protein 3 gene polymorphisms in recurrent pregnancy loss: A meta-analysis

BACKGROUND

Treg cells play an important role in development of tolerance in maternal immune system against the semi-allogenic embryo. Human forkhead box protein 3 (FOXP3) gene, is the major transcription factor responsible for the regulation of Treg function during pregnancy. Single nucleotide polymorphisms (SNPs) of FOXP3 gene have been reported as a risk factor for Recurrent Pregnancy Loss (RPL), however, results from previous studies are inconsistent.

METHODOLOGY

We have collected data from different studies to investigate the overall association of FOXP3 SNPs with risk of RPL. PubMed, Google Scholar, Elsevier, and Cochrane databases were searched to identify eligible studies. Odds Ratio (OR) and 95 % Confidence Interval (CI), calculated via fixed effect or random effect models, were used to evaluate strength of association. This meta-analysis included 11 studies (1383 RPL cases and 1413 controls) of 6 SNPs: rs3761548 A/C, rs2232365 A/G, rs2294021 T/C, 2280883 T/C, rs5902434del/ATT and rs141704699C/T, with ≥2 studies per SNPs and at least 1 significant result.

RESULTS

We observed that FOXP3 polymorphism was predominantly present in Asian women with history of RPL. rs2232365 A/G, rs3761548 A/C, rs2294021 T/C, rs2280883 T/C and rs5902434del/ATT polymorphisms were significantly associated with risk of RPL in Indian population. Further, among the most commonly seen polymorphism, rs3761548 A/C was significantly associated with risk of RPL in women from Kazakhstan, China and Gaza, Palestine; rs2232365 A/G in populations of Kazakhstan, Egypt, Iran and Gaza, Palestine. Results of this study indicates that FOXP3 polymorphism is significantly associated with risk of RPL, especially in Asians.

Gut Microbiota, Inflammation, and Probiotic Supplementation in Fetal Growth Restriction-A Comprehensive Review of Human and Animal Studies

Fetal growth restriction (FGR) is a pathological state that represents a fetus's inability to achieve adequate growth during pregnancy. Several maternal, placental, and fetal factors are likely associated with FGR etiology. FGR is linked to severe fetal and neonatal complications, as well as adverse health consequences in adulthood. Numerous randomized controlled trials (RCTs) have demonstrated improved growth in FGR fetuses with promising treatment strategies such as maternal micronutrient, amino acid, and nitric oxide supplementation. Elevated inflammation in pregnant women diagnosed with FGR has been associated with an imbalance between pro- and anti-inflammatory cytokines. Gut microbiota dysbiosis may result in increased FGR-related inflammation. Probiotic treatment may relieve FGR-induced inflammation and improve fetal growth. The aim of this review is to provide an overview of the gut microbiota and inflammatory profiles associated with FGR and explore the potential of probiotics in treating FGR.

Human Listeriosis

Listeria monocytogenes is a Gram-positive facultative intracellular pathogen that can cause severe invasive infections upon ingestion with contaminated food. Clinically, listerial disease, or listeriosis, most often presents as bacteremia, meningitis or meningoencephalitis, and pregnancy-associated infections manifesting as miscarriage or neonatal sepsis. Invasive listeriosis is life-threatening and a main cause of foodborne illness leading to hospital admissions in Western countries. Sources of contamination can be identified through international surveillance systems for foodborne bacteria and strains' genetic data sharing. Large-scale whole genome studies have increased our knowledge on the diversity and evolution of L. monocytogenes, while recent pathophysiological investigations have improved our mechanistic understanding of listeriosis. In this article, we present an overview of human listeriosis with particular focus on relevant features of the causative bacterium, epidemiology, risk groups, pathogenesis, clinical manifestations, and treatment and prevention.

A Whole Genome Sequencing-Based Epidemiological Investigation of a Pregnancy-Related Invasive Listeriosis Case in Central Italy

Listeriosis is currently the fifth most common foodborne disease in Europe. Most cases are sporadic; however, outbreaks have also been reported. Compared to other foodborne infections, listeriosis has a modest incidence but can cause life-threatening complications, especially in elderly or immunocompromised people and pregnant women. In the latter case, the pathology can be the cause of premature birth or spontaneous abortion, especially if the fetus is affected during the first months of gestation. The causative agent of listeriosis, Listeria monocytogenes, is characterized by the innate ability to survive in the environment and in food, even in adverse conditions and for long periods. Ready-to-eat food represents the category most at risk for contracting listeriosis. This study presents the result of an investigation carried out on a case of maternal-fetal transmission of listeriosis which occurred in 2020 in central Italy and which was linked, with a retrospective approach, to other cases residing in the same city of the pregnant woman. Thanks to the use of next-generation sequencing methodologies, it was possible to identify an outbreak of infection, linked to the consumption of ready-to-eat sliced products sold in a supermarket in the investigated city.

Deletion of ACLY Disrupts Histone Acetylation and IL-10 Secretion in Trophoblasts, Which Inhibits M2 Polarization of Macrophages: A Possible Role in Recurrent Spontaneous Abortion

Changes to macrophage polarization affect the local microenvironment of the placenta, resulting in pathological pregnancy diseases such as recurrent spontaneous abortion (RSA). Macrophages are in close contact with trophoblasts during placental development, and trophoblast-derived cytokines are important regulators of macrophage polarization and function. Histone acetylation can affect the expression and secretion of cytokines, and ATP citrate lyase (ACLY) is an important factor that regulates histone acetylation. The aim of this study was to investigate the effect of ACLY expression differences in trophoblast on macrophage polarization and its mechanism. Our data demonstrate that ACLY level in placental villi of patients with RSA is decreased, which may lead to the inhibition of histone acetylation in trophoblasts, thereby reducing the secretion of IL-10. Reduced IL-10 secretion activates endoplasmic reticulum stress in macrophages, thus inhibiting their M2 polarization.

Neglected listeria infection in pregnancy in China: 93 cases

OBJECTIVE

Listeriosis is a foodborne disease that occurs in immunocompromised patients. Pregnant women are a high-risk group for the disease. Listeria infection during pregnancy is uncommon in China because of dietary habits, with little clinician attention and minimal therapeutic options due to its population-specific nature.This article studies the clinical characteristics of Listeria infection in pregnant women and the improvement of treatment methods.

SUBJECTS

This study collected clinical data from 16 cases of pregnant patients with laboratory-confirmed Listeria monocytogenes infections at the Women and Children's Hospital of Jiaxing University. These data were combined with 77 cases that were reported in the literature for a total of 93 cases of Listeria monocytogenes infection in pregnancy that occurred in China over a 15-year interval.

METHODS

We collected the clinical data of 16 pregnant patients with listeriosis diagnosed in the laboratory of the Women and Children's Hospital of Jiaxing University from May 2013 to December 2020, and combined it with 77 cases of Listeria monocytogenes during pregnancy in China obtained from a literature search. We summarized the clinical features of listeriosis in pregnancy infection and investigated its treatment methods and prevention.

RESULTS

Ninety-three cases of Listeria monocytogenes infection in pregnancy occurred in early, middle and late pregnancy in 31, 27, and 35 patients, respectively. The initial clinical presentation was fever in 90 patients, intermittent lower abdominal pain in 50 patients, and abnormal fetal movement and/or abnormal fetal heartbeat in 27 cases. Specimens with a positive bacterial culture included the following: 6 amniotic fluid cultures, 35 blood cultures, 37 maternal placenta and uterine secretion cultures, and 15 neonatal blood cultures. Fifty-seven cases of placental pathology, all showing of neutrophil infiltration, were 100% consistent with acute chorioamnionitis. Fifty-eight patients were initially treated with cephalosporin antibiotics, and only 24 cases were initially treated with broad-spectrum penicillins to cover the pathogenic bacteria. Drug sensitivity tests revealed resistant strains, 15 penicillin G-resistant, 14 oxacillin-resistant, and 13 ampicillin-resistant strains. After penicillin failure, vancomycin or meropenem was given. Maternal outcomes included the following: 20 cases of sepsis, 3 cases of pneumonia, 6 cases of acute pyelonephritis, 28 cases of intrauterine infection, 2 cases of multiple organ dysfunction syndromes, and 1 case of septic shock. The fetal and neonatal outcomes were as follows: 16 cases of abortion, 16 cases of intrauterine fetal death, 22 cases of death after birth, and 39 cases of cure.

CONCLUSION

In our study and reported cases, Listeria monocytogenes in pregnancy is associated with fever as the primary manifestation, a high incidence of adverse pregnancy outcomes, and a significant increase in fetal and neonatal mortality. The low coverage of practical use of antimicrobial drugs and the emergence of drug-resistant strains in recent years have increased the difficulty of treatment, suggesting the need for clinicians to raise awareness of the disease and strengthen healthy diet promotion for women in pregnancy.

Decidual CXCR4+ CD56bright NK cells as a novel NK subset in maternal-foetal immune tolerance to alleviate early pregnancy failure

Natural killer (NK) cells preferentially accumulate at maternal-foetal interface and are believed to play vital immune-modulatory roles during early pregnancy and related immunological dysfunction may result in pregnant failure such as recurrent miscarriage (RM). However, the mechanisms underlying the establishment of maternal-foetal immunotolerance are complex but clarifying the roles of decidual NK (dNK) cells offers the potential to design immunotherapeutic strategies to assist RM patients. In this report, we analysed RNA sequencing on peripheral NK (pNK) and decidual NK cells during early pregnancy; we identified an immunomodulatory dNK subset CXCR4+ CD56bright dNK and investigated its origin and phenotypic and functional characteristics. CXCR4+ CD56bright dNK displayed a less activated and cytotoxic phenotype but an enhanced immunomodulatory potential relative to the CXCR4 negative subset. CXCR4+ CD56bright dNK promote Th2 shift in an IL-4-dependent manner and can be recruited from peripheral blood and reprogramed by trophoblasts, as an active participant in the establishment of immune-tolerance during early pregnancy. Diminished CXCR4+ dNK cells and their impaired ability to induce Th2 differentiation were found in RM patients and mouse models of spontaneous abortion. Moreover, adoptive transfer of CXCR4+ dNK cells to NK-deficient (Nfil3-/-) mice showed great therapeutic potential of CXCR4+ dNK via recovering the Th2/Th1 bias and reducing embryo resorption rates. The identification of this new dNK cell subset may lay the foundation for understanding NK cell mechanisms in early pregnancy and provide potential prognostic factors for the diagnosis and therapy of RM.

Foxp3 TSDR Hypermethylation Is Correlated with Decreased Tregs in Patients with Unexplained Recurrent Spontaneous Abortion

A decline of T regulatory cell (Treg) number and function is associated with unexplained recurrent spontaneous abortion (URSA). However, the mechanism of downregulation of Tregs in URSA patients is still unknown. This study aimed to investigate the changes of Tregs in URSA patients and the epigenetic regulation for these changes. Venous blood samples were collected from 20 patients with URSA and 20 healthy control subjects. Treg number and inhibitory capacity, and Foxp3 mRNA expression and Foxp3 TSDR methylation were compared between the 2 groups. Correlations between Treg frequency and inhibitory function and TSDR methylation status were examined by Spearman's correlation. The proportion of Tregs within the population of CD4⁺ T cells and the expression of Foxp3 mRNA was significantly lower in URSA patients than in healthy control subjects. Tregs from URSA patients and healthy controls both significantly inhibited the cytotoxic activity of natural killer (NK) cells toward K562 targets; however, the inhibitory ability of Tregs from URSA patients was significantly lower than that from healthy controls. The methylation level of the Treg-specific demethylated region (TSDR) in the Foxp3 gene was significantly greater in URSA patients than in the controls, and the level of methylation was inversely correlated with the proportion of Tregs and Foxp3 mRNA expression in the peripheral blood. However, the methylation level was not correlated with the inhibitory function of Tregs. A decrease of Treg number and function may be related to the pathogenesis of URSA, and Foxp3 hypermethylation may be associated with the decreased Treg number.

Perinatal listeriosis patients treated at a maternity hospital in Beijing, China, from 2013-2018

Background

Listeriosis is a rare but severe foodborne infectious disease. Perinatal listeriosis is often associated with septicemia, central nervous system (CNS) infection, and serious adverse pregnancy outcomes (miscarriage and neonate death). Here we report the characteristics and outcomes of perinatal listeriosis cases treated over 6 years at Beijing Obstetrics and Gynecology Hospital (BOGH), the largest maternity hospital in China.

Methods

We retrospectively reviewed the records of laboratory-confirmed, pregnancy-associated listeriosis cases treated from January 1, 2013 to December 31, 2018. The clinical manifestations, laboratory results, perinatal complications and outcomes (post-natal follow-up of 6 months) were investigated.

Results

In BOGH, 12 perinatal listeriosis cases were diagnosed based on Listeria monocytogenes positive culture, including 10 single pregnancies and 2 twin pregnancies. The corresponding incidence of pregnancy-associated listeriosis was 13.7/100,000 deliveries. Among those cases, four pregnant women and four newborns had septicemia, and two of the neonates with septicemia also suffered CNS infection. All the maternal patients recovered. Two inevitable miscarriages and four fetal stillbirths occurred. Of the eight delivered newborns, six survived, and two died within 2 days from birth. None of the survivors had neurological sequelae during a 6-month follow-up. The overall feto-neonatal fatality rate was 57.1%; notably, this rate was 100% for infections occurring during the second trimester of pregnancy and only 14.3% for those occurring in the third trimester.

Conclusions

Perinatal listeriosis is associated with high feto-neonatal mortality, and thus, a public health concern. Additional large-scale studies are needed to strengthen the epidemiological understanding of listeriosis in China.

Seroprevalence of Malaria and Hepatitis B Coinfection among Pregnant Women in Tamale Metropolis of Ghana: A Cross-Sectional Study

Background

Coinfections are becoming common risk factors that may contribute to the increased burden of morbidity in pregnancy. The aim of this study was to assess the seroprevalence of coinfections of malaria, hepatitis B (HBV), human immunodeficiency virus (HIV), and syphilis among pregnant women attending antenatal clinics (ANC) in the Tamale Metropolis.

Methods

By means of rapid diagnostic tests (RDTs), pregnant women attending the Tamale Teaching Hospital (TTH) were screened for malaria, HBV infection, HIV infection, and syphilis from March 2013 to February 2015. Haemoglobin (Hb) values, sickling, and glucose-6-phosphate dehydrogenase deficiency (G6PDd) statuses were also assessed using full blood count (FBC), sodium metabisulphite, and methaemoglobin reduction tests, respectively. Logistic regression analysis was performed to estimate the risks/odds ratios (ORs) for the coinfections and other variables (age, gravidity, and time of the first ANC visit) with 95% confidence intervals (CIs) and set p values for accepting any differences at <0.05.

Results

Within the two-year study period, data were collected from 3,127 pregnant women. The mean age (SD) of the pregnant women was 28.5 (±5.0) years. Of the total number, seroprevalence was high for malaria (11.6%) and HBV infection (4.2%) and low for HIV infection (1.0%) and syphilis (0.4%) monoinfections. Mal/HBV coinfection was higher (0.7%) when compared with Mal/HIV (0.1%), Mal/syphilis (0.0%), HBV/HIV (0.0%), HBV/syphilis (0.1%), and HIV/syphilis (0.0%) coinfections. The mean Hb (g/dl) for the women with the four monoinfections was significantly different from one another (p=0.009). Pregnant women with malaria infection were about 2 times more likely to be coinfected with HBV even after adjusting for potential confounders (adjusted odds ratio (AOR) = 1.66, 95% CI = 1.04-2.65, p=0.031). Those in their third trimester and visiting the ANC for the first time were significantly less likely to be infected with HBV (AOR = 0.45, 95% CI = 0.28-0.73, p=0.001), with malaria/HBV coinfection (AOR = 0.09, 95% CI = 0.01-0.68, p=0.020), and with any coinfection (AOR = 0.19, 95% CI = 0.06-0.63, p=0.007).

Conclusion

A comparatively high seroprevalence of malaria and its coinfection with HBV in pregnant women was observed in this study. Considering the effects that both malaria and HBV have on the liver, it would be expedient to conduct further studies to assess liver function among malaria/HBV-infected individuals, while interventions to prevent coinfections among pregnant women are intensified.

Maternal N-Carbamylglutamate Supply during Early Pregnancy Enhanced Pregnancy Outcomes in Sows through Modulations of Targeted Genes and Metabolism Pathways

Reducing pregnancy loss is important for improving reproductive efficiency for both human and mammalian animals. Our previous study demonstrates that maternal N-carbamylglutamate (NCG) supply during early pregnancy enhances embryonic survival in gilts. However, whether maternal NCG supply improves the pregnancy outcomes is still not known. Here we found maternal NCG supply during early pregnancy in sows significantly increased the numbers of total piglets born alive per litter ( P < 0.05) and significantly changed the levels of metabolites in amniotic fluid and serum involved in metabolism of energy, lipid, and glutathione and immunological regulation. The expression of endometrial progesterone receptor membrane component 1 (PGRMC1) was significantly increased by NCG supplementation ( P < 0.05) as well as the expression of PGRMC1, endothelial nitric oxide synthesases (eNOS), and lamin A/C in fetuses and placentae ( P < 0.05). Among the NCG-associated amino acids, arginine and glutamine, markedly increased PGRMC1 and eNOS expression in porcine trophectoderm cells ( P < 0.05), whereas glutamate could stimulate the expression of vimentin and lamin A/C in porcine trophectoderm (pTr) cells ( P < 0.05) and proline stimulated lamin A/C expression ( P < 0.05). Collectively, these data reveal the mechanisms of NCG in reducing early embryo loss. These findings have important implications that NCG has great potential to improve pregnancy outcomes in human and mammalian animals.

Uterine CD56dim and CD16+ Cells in Refractory Antiphospholipid Antibody-Related Pregnancy Loss and Chromosomally Intact Abortuses: A Case-Control Study

AIM

To evaluate the role of uterine natural killer (uNK) CD56^dim and CD16⁺ cells in patients with refractory antiphospholipid, antibody-mediated, recurrent, pregnancy loss.

SETTINGS AND DESIGN

A case-control study was conducted between 2012 and 2015 at a university hospital.

PATIENTS AND METHODS

A group of 118 women with a history of antiphospholipid antibody syndrome experiencing fetal loss in spite of low dose aspirin (LDA) and low molecular weight heparin (LMWH) treatment in the current pregnancy were included in this study. A group of 32 patients undergoing an elective termination of viable pregnancies before 20 weeks were taken as controls. Suction evacuation was performed to collect abortus specimens, and uterine wall curettage was performed to collect decidua specimens, which were then stained using monoclonal antibodies specific to CD56 and CD16.

STATISTICS

Statistical analyses were performed using the Statistical Package for the Social Sciences version 18 software. Chi-square and Fisher exact tests were used for making comparison between the groups.

RESULTS

Abnormal fetal karyotype was found in nine (9/97) cases of the study group, which means that abnormal karyotype accounts for only 9.3% of the causes of failure of treatment. Abnormal karyotype was found in four cases of the control group. Only cases with normal karyotyping were subjected to decidual uNK cells analysis. We found that CD56^dim and CD16⁺ were found in the decidua of 79 cases (79/97), which means that aberrant natural killer cells expression might account for 81.4% of the cases of refractory antiphospholipid antibody (APA)-mediated recurrent pregnancy loss.

CONCLUSION

CD56^dim and CD16⁺ uNK cells might be correlated with refractory APA-mediated recurrent pregnancy loss.

Expression of CD24 and Siglec-10 in first trimester placenta: implications for immune tolerance at the fetal-maternal interface

During pregnancy, the fetal-maternal interface establishes immune tolerance between the fetus and the mother. CD24, a mucin-like glycoprotein expressed at the surface of hematopoietic cells and diverse tumor cells, is known to interact with the sialic acid-binding immunoglobulin-type lectins (Siglecs). This interaction was assessed as a candidate complex for the immune suppression response in the placenta. CD24 was affinity purified from term placenta and characterized by SDS-PAGE, Western blot and ELISA. Binding of recombinant Siglecs to placental CD24 was evaluated by ELISA. The expression of CD24 and Siglec-10 in first trimester placental tissues was investigated by immunohistochemistry and immunofluorescence. Placental CD24 had an apparent molecular weight of 30-70 kDa consistent with its high degree of N- and O-linked glycosylation. EDTA-sensitive CD24-Siglec-10 interaction via the terminal sialic acid glycan residues of CD24 was observed. CD24 did not interact with Siglec-3 or Siglec-5. During the first trimester, and already in gestational week (GA) 8, CD24 showed high expression in villous and extravillous cytotrophoblasts. There was also a mild expression in stromal cells, while syncytiotrophoblasts were negative. Co-localization of CD24 with Siglec-10 was observed in endometrial glands and in first trimester decidual cells in close vicinity to extracellular trophoblasts. This study is the first to demonstrate the early presence of CD24 in the placenta cytotrophoblast layers, placental bed and maternal uterine glands. The presence of the CD24-Siglec-10 in these regions of fetal-maternal interactions suggests a possible role in mediating immune tolerance at the fetal-maternal interface.

Selenium status in U.K. pregnant women and its relationship with hypertensive conditions of pregnancy

Dietary intake/status of the trace mineral Se may affect the risk of developing hypertensive conditions of pregnancy, i.e. pre-eclampsia and pregnancy-induced hypertension (PE/PIH). In the present study, we evaluated Se status in U.K. pregnant women to establish whether pre-pregnant Se status or Se supplementation affected the risk of developing PE/PIH. The samples originated from the SPRINT (Selenium in PRegnancy INTervention) study that randomised 230 U.K. primiparous women to treatment with Se (60 μg/d) or placebo from 12 weeks of gestation. Whole-blood Se concentration was measured at 12 and 35 weeks, toenail Se concentration at 16 weeks, plasma selenoprotein P (SEPP1) concentration at 35 weeks and plasma glutathione peroxidase (GPx3) activity at 12, 20 and 35 weeks. Demographic data were collected at baseline. Participants completed a FFQ. U.K. pregnant women had whole-blood Se concentration lower than the mid-range of other populations, toenail Se concentration considerably lower than U.S. women, GPx3 activity considerably lower than U.S. and Australian pregnant women, and low baseline SEPP1 concentration (median 3.00, range 0.90-5.80 mg/l). Maternal age, education and social class were positively associated with Se status. After adjustment, whole-blood Se concentration was higher in women consuming Brazil nuts (P= 0.040) and in those consuming more than two seafood portions per week (P= 0.054). A stepwise logistic regression model revealed that among the Se-related risk factors, only toenail Se (OR 0.38, 95% CI 0.17, 0.87, P= 0.021) significantly affected the OR for PE/PIH. On excluding non-compliers with Se treatment, Se supplementation also significantly reduced the OR for PE/PIH (OR 0.30, 95% CI 0.09, 1.00, P= 0.049). In conclusion, U.K. women have low Se status that increases their risk of developing PE/PIH. Therefore, U.K. women of childbearing age need to improve their Se status.

Cnr2 deficiency confers resistance to inflammation-induced preterm birth in mice

Infection-induced inflammation, frequently associated with increased production of proinflammatory cytokines, is considered a significant contributor to preterm birth. A G protein-coupled cannabinoid receptor 2 (CB2), encoded by Cnr2, is expressed in various immune cells and was shown to modulate immune responses. We show here that Cnr2, but not Cnr1, deficient mice are resistant to lipopolysaccharide (LPS)-driven preterm birth and suppression of serum progesterone levels. After LPS challenge, Cnr2(-/-) mice exhibited increased serum levels of IL-10 with decreased IL-6 levels. These changes were associated with reduced LPS-induced Ptgs2 expression at the maternal-conceptus interface on day 16 of pregnancy. LPS stimulation of Cnr2(-/-) dendritic cells in vitro resulted in increased IL-10 with reduced IL-6 production and correlated with increased cAMP accumulation. Collectively, our results suggest that increased IL-10 production occurring via augmented cAMP accumulation represents a potential mechanism for the resistance of Cnr2(-/-) mice to LPS-induced preterm birth. These results may have clinical relevance, because currently, there are limited options to prevent preterm birth.

Listeriosis during Pregnancy: A Public Health Concern

Listeria was first described in 1926 by Murray, Webb, and Swann, who discovered it while investigating an epidemic infection among laboratory rabbits and guinea pigs. The role of Listeria monocytogenes as a foodborne pathogen was definitively recognized during the 1980s. This recognition was the consequence of a number of epidemic human outbreaks due to the consumption of contaminated foods, in Canada, in the USA and in Europe. Listeriosis is especially severe in immunocompromised individuals such as pregnant women. The disease has a low incidence of infection, although this is undeniably increasing, with a high fatality rate amongst those infected. In pregnant women listeriosis may cause abortion, fetal death, or neonatal morbidity in the form of septicemia and meningitis. Improved education concerning the disease, its transmission, and prevention measures for immunocompromised individuals and pregnant women has been identified as a pressing need.

Fetal regulatory T cells and peripheral immune tolerance in utero: implications for development and disease

The developing fetus must actively learn to tolerate benign antigens or suffer the consequences of broken tolerance. Tolerance of self-antigens prevents development of autoimmune diseases and is achieved by both deletion of autoreactive T cell clones in the thymus (central tolerance) and by the suppressive influence of CD4(+)  CD25(+)  FoxP3(+) regulatory T cells (Tregs) in the periphery. Fetal CD4(+) T cells have a strong predisposition to differentiate into tolerogenic Tregs that actively promote self-tolerance, as well as tolerance to non-inherited antigens on chimeric maternal cells that reside in fetal tissues. As the fetus nears birth, a crucial transition must occur between the tolerogenic fetal immune system and a more defensive adult-type immune system that is able to combat pathogens. This paper will review the unique tolerogenic nature of fetal T cells and will examine evidence for a novel model of fetal immune development: the layered immune system hypothesis.

Colostrogenesis: candidate genes for IgG1 transcytosis mechanisms in primary bovine mammary epithelial cells

Bovine colostrogenesis is distinguished by the specific transfer of IgG1 from the blood to mammary secretions. The process has been shown to be initiated by hormones and occurs during the last weeks of pregnancy when steroid concentrations of estradiol (E2 ) and progesterone (P4 ) are highly elevated. Rodent intestinal uptake of immunoglobulin G is mediated by a receptor termed Fc fragment of IgG, Receptor, Transporter, alpha (FcGRT) and supported by light chain Beta-2-Microglobulin (β2M). We hypothesized that steroid hormone treatments (E2 and P4 ) of bovine mammary epithelial cells in vitro would induce up-regulation of IgG1 transcytosis candidate gene mRNA expression suggesting involvement in IgG1 transcytosis. Two different primary bovine mammary epithelial cell cultures were cultured on plastic and rat tail collagen and treated with hormonal combinations (steroids/lactogenic hormones). Evaluated mRNA components were bLactoferrin (bLf: a control), bFcGRT, β2M, and various small GTPases; the latter components are reported to direct endosomal movements in eukaryotic cells. All tested transcytosis components showed strong expression of mRNA in the cells. Expression of bFcGRT, bRab25 and bRhoB were significantly up-regulated (p < 0.05) by steroid hormones. bRab25 and bRhoB showed increased expression by steroid treatments, but also with lactogenic hormones. Analysis for the oestrogen receptor (ER) mRNA was mostly negative, but 25% of the cultures tested exhibited weak expression, while the progesterone receptor (PR) mRNA was always detected. bRab25 and bRhoB and likely bFcGRT are potential candidate genes for IgG1 transcytosis in bovine mammary cells.

Blockage of heme oxygenase-1 abrogates the protective effect of regulatory T cells on murine pregnancy and promotes the maturation of dendritic cells

Regulatory T cells (Treg) play an important role in fetal protection. They expand during normal pregnancy and protect fetal antigens from maternal effector cells. Their effect is associated with the up-regulation of tolerance-associated molecules at the fetal-maternal interface. Among these, Heme Oxygenase-1 (HO-1, coded by Hmox1) is of special importance as its blockage correlates with increased abortion rates and its up-regulation positively affects pregnancy outcome. Here, we aimed to investigate whether the protective effect of Treg is mediated by HO-1 in a mouse model. HO-1 blockage by Zinc Protoporhyrin (ZnPPIX) abrogated the protective effect of Treg transfer. We found that HO-1 is important in maintaining maternal dendritic cells (DCs) in an immature state, which contributes to the expansion of the peripheral Treg population. This brings to light one essential pathway through which Treg mediates the semi-allogeneic fetus tolerance.

Listeriosis in pregnancy: a secular trend in a tertiary referral hospital in Barcelona

The purpose of this study was to describe the variation in listeriosis infection incidence during pregnancy over a 25-year period based on salient clinical and laboratory features compiled in a tertiary referral hospital and to depict the clinical characteristics of these cases. A cohort was created of all cases of listeriosis in pregnant women or their neonates (early-onset form) diagnosed between 1985 and 2010. Forty-three cases of perinatal listeriosis were diagnosed among the 82,320 hospitalised pregnant women (incidence 0.5‰). Whereas the incidence remained almost constant at 0.24‰ until 2000, an increasing incidence was observed from then on, reaching 0.86‰ during the last years of the study period. A four-fold increase in listeriosis rate during pregnancy has occurred in recent years, with poorer outcome for those cases occurring before 28 weeks and for those in which early antibiotic treatment was not provided. These results should raise the awareness of the agencies and professionals involved in prenatal care.

Association between functional polymorphisms of Foxp3 gene and the occurrence of unexplained recurrent spontaneous abortion in a Chinese Han population

Unexplained recurrent spontaneous abortion (URSA) is an alloimmune disease associated with the failure of fetal-maternal immunologic tolerance in which the regulatory T lymphocytes (Treg) play a pivotal role. It is well known that Forkhead box P3 (Foxp3) is a crucial regulatory factor for the development and function of Treg cells. It has also been established that deficiency of the Foxp3 gene suppresses the regulatory function of Treg cells. To determine if functional polymorphisms at the Foxp3 loci are associated with URSA in humans, we genotyped four common polymorphisms of Foxp3 gene in 146 unrelated URSA patients and 112 healthy women. The results showed that rs3761548A/C and rs2232365A/G polymorphisms were significantly associated with URSA. Additionally, we found that the allelic distribution of rs5902434 del/ATT in URSA group was slightly different from that in the control group. We conclude that functional polymorphisms of the Foxp3 gene may confer an important susceptibility to URSA in the Chinese Han population, probably by altering Foxp3 function and/or its expression.