Peripheral CD300a+CD8+ T lymphocytes with a distinct cytotoxic molecular signature increase in pregnant women with chronic chorioamnionitis

Intra-amniotic inflammation in the mid-trimester of pregnancy is a risk factor for neuropsychological disorders in childhood

OBJECTIVES

Intra-amniotic inflammation is a subclinical condition frequently caused by either microbial invasion of the amniotic cavity or sterile inflammatory stimuli, e.g., alarmins. An accumulating body of evidence supports a role for maternal immune activation in the genesis of fetal neuroinflammation and the occurrence of neurodevelopmental disorders such as cerebral palsy, schizophrenia, and autism. The objective of this study was to determine whether fetal exposure to mid-trimester intra-amniotic inflammation is associated with neurodevelopmental disorders in children eight to 12 years of age.

METHODS

This is a retrospective case-control study comprising 20 children with evidence of prenatal exposure to intra-amniotic inflammation in the mid-trimester and 20 controls matched for gestational age at amniocentesis and at delivery. Amniotic fluid samples were tested for concentrations of interleukin-6 and C-X-C motif chemokine ligand 10, for bacteria by culture and molecular microbiologic methods as well as by polymerase chain reaction for eight viruses. Neuropsychological testing of children, performed by two experienced psychologists, assessed cognitive and behavioral domains. Neuropsychological dysfunction was defined as the presence of an abnormal score (<2 standard deviations) on at least two cognitive tasks.

RESULTS

Neuropsychological dysfunction was present in 45% (9/20) of children exposed to intra-amniotic inflammation but in only 10% (2/20) of those in the control group (p=0.03). The relative risk (RR) of neuropsychological dysfunction conferred by amniotic fluid inflammation remained significant after adjusting for gestational age at delivery [aRR=4.5 (1.07-16.7)]. Of the 11 children diagnosed with neuropsychological dysfunction, nine were delivered at term and eight of them had mothers with intra-amniotic inflammation. Children exposed to intra-amniotic inflammation were found to have abnormalities in neuropsychological tasks evaluating complex skills, e.g., auditory attention, executive functions, and social skills, whereas the domains of reasoning, language, and memory were not affected in the cases and controls.

CONCLUSIONS

Asymptomatic sterile intra-amniotic inflammation in the mid-trimester of pregnancy, followed by a term birth, can still confer to the offspring a substantial risk for neurodevelopmental disorders in childhood. Early recognition and treatment of maternal immune activation in pregnancy may be a strategy for the prevention of subsequent neurodevelopmental disorders in offspring.

Comprehensive analysis of immune-related genes associated with the microenvironment of patients with unexplained infertility

Background

Disturbances in immunological responses and modulation lead to implantation and pregnancy failure and might be involved in the pathogenesis of infertility. This project aimed to screen and identify immune-related genes as potential biomarkers for treatment.

Methods

Gene expression profiles were obtained from Gene Expression Omnibus (GEO) databases. Differentially expressed genes (DEGs) were screened using GEO 2R to explore potential biomarkers. Protein-protein interaction (PPI) network analysis and functional enrichment analysis were applied to explore possible mechanisms. The deconvolution algorithm [referred to as Cell-type Identification by Estimating Relative Subsets of RNA Transcripts (CIBERSORT)] was employed to assess tissue-infiltrating immune cells. Western blot analysis and immunohistochemistry (IHC) were conducted for determination of protein levels.

Results

In this research, we identified 24 candidate immune-related DEGs via combined DEGs and functional analysis. We also found that the ratio of M0 macrophages and resting mast cells was higher in infertile group (P<0.05), whereas the amounts of activated natural killer (NK) cells was significantly lower compared with the control group (P<0.05). Furthermore, we evaluated the relationship between immune cells and candidate genes and found that 17 genes were related to M0 macrophages, resting mast cells, or activated NK cells. The genes CD40, PRF1, and EDN3 were chosen based on validation from independent datasets. Finally, our clinical samples confirmed the expression of the 3 genes.

Conclusions

The study recognized 3 genes that are signatures and could be potential biomarkers for unexplained infertility. These genes might guide the immunotherapy of these patients and become new treatment targets.

Pan-cancer analysis identifies CD300 molecules as potential immune regulators and promising therapeutic targets in acute myeloid leukemia

BACKGROUND

CD300s are a group of proteins playing vital roles in immune responses. However, much is yet to be elucidated regarding the expression patterns and clinical significances of CD300s in cancers.

METHODS

In this study, we comprehensively investigated CD300s in a pan-cancer manner using multi-omic data from The Cancer Genome Atlas. We also studied the relationship between CD300s and the immune landscape of AML.

RESULTS

We found that CD300A-CD300LF were generally overexpressed in tumors (especially AML), whereas CD300LG was more often downregulated. In AML, transactivation of CD300A was not mediated by genetic alterations but by histone modification. Survival analyses revealed that high CD300A-CD300LF expression predicted poor outcome in AML patients; the prognostic value of CD300A was validated in seven independent datasets and a meta dataset including 1115 AML patients. Furthermore, we demonstrated that CD300A expression could add prognostic value in refining existing risk models in AML. Importantly, CD300A-CD300LF expression was closely associated with T-cell dysfunction score and could predict response to AML immunotherapy. Also, CD300A was found to be positively associated with HLA genes and critical immune checkpoints in AML, such as VISTA, CD86, CD200R1, Tim-3, and the LILRB family genes.

CONCLUSIONS

Our study demonstrated CD300s as potential prognostic biomarker and an ideal immunotherapy target in AML, which warrants future functional and clinical studies.

The Role of IL-27 in the Systemic Inflammatory Response That Accompanies Preterm Labour

This study aimed to investigate whether interleukin-27 (IL-27) activates maternal peripheral blood mononuclear cells (PBMCs) and induces inflammatory responses in amniotic epithelial cells in preterm labour (PL). The expression of IL-27p28, EBI3 and IL-27Rα was compared in maternal PBMCs of the PL, term labour (TL) and term not in labour (TNL) groups. The relationship between IL-27 and molecules associated with PBMC activation was investigated using bioinformatic and quantitative reverse transcription polymerase chain reaction (qRT-PCR) analyses. We investigated the inflammatory effects of IL-27 in PBMCs and its underlying mechanisms in vitro. In addition, we treated amniotic epithelial cells (WISH cells) with a PBMC-conditioned medium to identify the inflammatory effects of IL-27-treated PBMCs in amniotic epithelial cells. The expression of IL-27p28 and IL-27Rα in PBMCs of the PL group was higher than that in the TL/TNL groups. Bioinformatic analysis revealed that IL-27 was positively correlated with IFNG, IL6, IL1β, CXCL10 and ICAM1 in the whole blood samples of pregnant women in the PL group, which was confirmed using qRT-PCR. Furthermore, rhIL-27 promoted the expression of Th1 cell-related molecules (T-bet, IFN-γ and ICAM-1) and proinflammatory cytokines (IL-6 and IL-1β) in PBMCs in vitro, which was partially mediated by the JAK2/STAT1 pathway. In addition, it enhanced the expression of IL-27p28, EBI3 and IL-27Rα in PBMCs. Moreover, the expression of IL-6, IL-1β and TNF-α in WISH cells was significantly increased by the conditional medium derived from IL-27-treated PBMCs. IL-27 upregulated the expression of Th1 cell-related molecules and proinflammatory cytokines in PBMCs partially mediated by the JAK2/STAT1 pathway. Inflammatory responses were induced in WISH cells by a conditional medium derived from IL-27-treated PBMCs. Therefore, IL-27 may contribute to PL by promoting inflammation in maternal PBMCs and amniotic epithelial cells.

Impact of CMV and age on T cell subsets defined by CD161, CD300a, and/or CD57 expression in healthy Andalusians

Immunosenescence affects innate and adaptive immunity impairing the response to pathogens and vaccines. Chronic infection with cytomegalovirus (CMV) has been shown to drive 'early immunosenescence' and can considerably impact both the function and phenotype of immune cells, especially T cells. We have previously shown that the expression of CD57, CD300a, and CD161 was differentially affected by age and chronic CMV infection, indicating that these markers are a hallmark of CMV infection and T cell ageing. The aim of this present study was to clarify whether these three markers define distinct T cell subpopulations with a specific functional and molecular signature. Specifically, we analyzed the effect of age and chronic CMV infection on the functionality of T cells according to CD161, CD300a, and CD57 expression. We found that these markers defined different T cell subsets, both at the phenotypic and functional levels. CD57 was the best biomarker for CD4+ T cell cytotoxicity and was a hallmark of CMV infection. CD300a+ T cells were heterogeneous and included different cell subsets. The population of CD161+ T cells dramatically decreased with age, independently of CMV infection, and represented a sign of age-associated immune system alterations. The latter could contribute to an increased risk of autoimmune disease and infection in older adults. Our results underline the importance of better understanding the factors involved in the immunosenescence process to be able to uncover new biomarkers and open new avenues for the investigation and development of novel age-related disease therapies.

INTERGROWTH-21 Identifies High Prevalence of Low Symphysis-Fundal Height in Indigenous Pregnant Women Experiencing Multiple Infections, Nutrient Deficiencies, and Inflammation: The Maternal Infections, Nutrient Deficiencies, and Inflammation (MINDI) Cohort

BACKGROUND

In the absence of ultrasound, symphysis-fundal height (SFH) can assess maternal-fetal well-being as it is associated with gestational age, fetal weight, and amniotic fluid volume. However, other modifiers of SFH, including maternal infections, nutrient deficiencies, and inflammation (MINDI), have not been widely explored.

OBJECTIVES

Our objectives were 2-fold: 1) to assess prevalence of low SFH in indigenous Panamanian women using both Pan-American Health Organization (PAHO) and INTERGROWTH-21 standards and 2) to explore associations of SFH with maternal health indicators: infections (oral, skin, urogenital, nematode infections), nutrient deficiencies [protein and iron indicators (ferritin, serum iron, serum transferrin receptor, hepcidin), folate, and vitamins A, D, and B-12], and inflammation [leukocytes, C-reactive protein (CRP), cytokines].

METHODS

For this cross-sectional study, low-SFH-for-gestational-age was assessed using PAHO and INTERGROWTH <10th centile in 174 women at ≥16 weeks of gestation. Bootstrapping selected MINDI variables for inclusion in multivariable fractional polynomial (MFP) logistic regressions for low SFH. Associations of MINDI variables with hepcidin were also investigated.

RESULTS

Prevalence of low SFH was 8% using PAHO, but using INTERGROWTH, 50.6% had SFH <10th centile, including 37.9% <3rd centile. Both PAHO-SFH <10th centile and INTERGROWTH-SFH <3rd centile were associated with higher hepcidin (OR = 1.12, P = 0.008, and OR = 3.04, P = 0.001, respectively) and with lower TNF-α (OR = 0.73, P = 0.012, and OR = 0.93, P = 0.015, respectively). Wood-smoke exposure increased the odds of PAHO-SFH <10th centile (OR = 1.19, P = 0.009), whereas higher BMI decreased the odds of INTERGROWTH-SFH <3rd centile (OR = 0.87, P = 0.012). Lower pulse pressure (OR = 0.90, P = 0.009) and lower inflammatory responses [lower lymphocytes (OR = 0.21, P = 0.026), IL-17 (OR = 0.89, P = 0.011)] distinguished SFH <3rd centile from SFH ≥3rd to <10th centiles using INTERGROWTH-21 standards. The MFP regression for hepcidin controlling for SFH (adjusted R 2 = 0.40, P = 0.001) revealed associations with indicators of inflammation (CRP, P < 0.0001; IL-17, P = 0.012), acidic urinary pH (P = 0.008), and higher intake of supplements (P = 0.035).

CONCLUSIONS

Associations of low SFH with MINDI variables, including hepcidin, highlight its potential for early detection of multicausal in utero growth faltering.

The determinant role of IL-6 in the establishment of inflammation leading to spontaneous preterm birth

Preterm birth (PTB) and its consequences are a major public health concern as preterm delivery is the main cause of mortality and morbidity at birth. There are many causes of PTB, but inflammation is undeniably associated with the process of premature childbirth and fetal injury. At present, treatments clinically available mostly involve attempt to arrest contractions (tocolytics) but do not directly address upstream maternal inflammation on development of the fetus. One of the possible solutions may lie in the modulation of inflammatory mediators. Of the many pro-inflammatory cytokines involved in the induction of PTB, IL-6 stands out for its pleiotropic effects and its involvement in both acute and chronic inflammation. Here, we provide a detailed review of the effects of IL-6 on the timing of childbirth, its occurrence during PTB and its indissociable roles with associated fetal tissue damage.

Functional significance of lymphocytes in pregnancy and lymphocyte immunotherapy in infertility: A comprehensive review and update

During pregnancy, the fetal-maternal interface underlies several dynamic alterations to permit the fetus to be cultivated and developed in the uterus, in spite of being identifies by the maternal immune system. A large variety of decidual leukocyte populations, including natural killer cells, NKT cells, innate lymphoid cells, dendritic cells, B cells, T cells, subpopulations of helper T cells play a vital role in controlling the trophoblast invasion, angiogenesis as well as vascular remodeling. In contrast, several regulatory immunosuppressive mechanisms, including regulatory T cells, regulatory B cells, several cytokines and mediators are involved in maintain the homeostasis of immune system in the fetal-maternal interface. Nonetheless, aberrant alterations in the balance of immune inflammatory or immunosuppressive arms have been associated with various pregnancy losses and infertilities. As a result, numerous strategies have been developed to revers dysregulated balance of immune players to increase the chance of successful pregnancy. Lymphocyte immunotherapy has been developed through utilization of peripheral white blood cells of the husband or others and administered into the mother to confer an immune tolerance for embryo's antigens. However, the results have not always been promising, implying to further investigations to improve the approach. This review attempts to clarify the involvement of lymphocytes in contributing to the pregnancy outcome and the potential of lymphocyte immunotherapy in treatment of infertilities with dysregulated immune system basis.

Immunobiology of Acute Chorioamnionitis

Acute chorioamnionitis is characterized by neutrophilic infiltration and inflammation at the maternal fetal interface. It is a relatively common complication of pregnancy and can have devastating consequences including preterm labor, maternal infections, fetal infection/inflammation, fetal lung, brain, and gastrointestinal tract injury. In this review, we will discuss current understanding of the pathogenesis, immunobiology, and mechanisms of this condition. Most commonly, acute chorioamnionitis is a result of ascending infection with relatively low-virulence organisms such as the Ureaplasma species. Furthermore, recent vaginal microbiome studies suggest that there is a link between vaginal dysbiosis, vaginal inflammation, and ascending infection. Although less common, microorganisms invading the maternal-fetal interface via hematogenous route (e.g., Zika virus, Cytomegalovirus, and Listeria) can cause placental villitis and severe fetal inflammation and injury. We will provide an overview of the knowledge gleaned from different animal models of acute chorioamnionitis and the role of different immune cells in different maternal-fetal compartments. Lastly, we will discuss how infectious agents can break the maternal tolerance of fetal allograft during pregnancy and highlight the novel future therapeutic approaches.

Polyfunctional HIV-1 specific response by CD8+ T lymphocytes expressing high levels of CD300a

CD300a receptor is found on different CD8+ T cell subsets and its expression has been associated to a more cytotoxic molecular signature. CD300a has an important role in some viral infections and its expression levels are known to be modulated by human immunodeficiency virus (HIV)−1 infection on several cell types. The main objective of this work was to investigate CD300a expression and its regulation during HIV-1 specific CD8+ T cell responses. CD300a receptor expression was analysed by multiparametric flow cytometry on CD8+ T lymphocytes from HIV negative donors, naive HIV-1+ individuals and HIV-1+ subjects under suppressive combined antiretroviral therapy (cART). HIV-1 specific CD8+ T cell response was studied by stimulating cells with HIV-1 derived peptides or with a Gag HIV-1 peptide. Our results showed that HIV-1 specific CD8+ T cells expressing higher levels of CD300a were more polyfunctional showing an increased degranulation and cytokine production. Moreover, we observed an up-regulation of CD300a expression after Gag HIV-1 peptide stimulation. Finally, our results demonstrated an inverse correlation between CD300a expression on CD8+ T lymphocytes and HIV disease progression markers. In conclusion, CD300a expression is associated to a better and more polyfunctional HIV-1 specific CD8+ T cell response.

Immune responses in women with periodontitis and preterm low birth weight: Levels of CD4+ and CD8+ T cells in gingival granulation tissue

OBJECTIVE

Preterm Low-Birth-Weight (PLBW) is frequently associated with periodontal disease. However, the mechanism is still unknown. The present study was performed to examine the possible link between periodontal infections and PLBW in post-partum women utilizing clinical parameters and CD4+ and CD8 + T lymphocytes ratio in gingival granulation tissue.

MATERIALS

The tissues used in this study consisted of 35 gingival granulation tissue biopsies from 35 mothers of healthy infants (HTBW), 35 biopsies of gingival granulation tissue from 35 mothers of PLBW within one month postpartum and gingival tissue biopsies from 7 control individual with no periodontal disease (HC). CD4+ and CD8 + T lymphocyte ratios in a unit area of the gingival granulation tissue were determined by hystometrically. Statistical analysis was performed by using Kruskal-Wallis and Mann-Whitney U tests.

RESULTS

CD8 + T lymphocytes were more prevalent in the PLBW group than in the HTBW and HC group (P < 0.05). The CD4+/CD8+ ratio in the PLBW group was lower than those of the other groups (p < 0.05). There were no statistically significant differences in CD4 + T lymphocytes counts between all groups (P > 0.05).

CONCLUSION

Within the limits of this study it can be concluded that CD8 + T lymphocytes in gingival tissue may play important roles in the pathogenesis of periodontitis and PLBW.

Are B cells altered in the decidua of women with preterm or term labor?

PROBLEM

The immunophenotype of B cells at the maternal-fetal interface (decidua) in labor at term and preterm labor is poorly understood.

METHOD OF STUDY

Decidual tissues were obtained from women with preterm or term labor and from non-labor gestational age-matched controls. Immunophenotyping of decidual B cells was performed using multicolor flow cytometry.

RESULTS

(a) In the absence of acute or chronic chorioamnionitis, total B cells were more abundant in the decidua parietalis of women who delivered preterm than in those who delivered at term, regardless of the presence of labor; (b) decidual transitional and naïve B cells were the most abundant B-cell subsets; (c) decidual B1 B cells were increased in women with either labor at term or preterm labor and chronic chorioamnionitis compared to those without this placental lesion; (d) decidual transitional B cells were reduced in women with preterm labor compared to those without labor; (e) naïve, class-switched, and non-class-switched B cells in the decidual tissues underwent mild alterations with the process of preterm labor; (f) decidual plasmablasts seemed to increase in women with either labor at term or preterm labor with chronic chorioamnionitis; and (g) decidual B cells expressed high levels of interleukin (IL)-12, IL-6, and/or IL-35.

CONCLUSION

Total B cells are not increased with the presence of preterm or term labor; yet, specific subsets (B1 and plasmablasts) undergo alterations in women with chronic chorioamnionitis. Therefore, B cells are solely implicated in the pathological process of preterm labor in a subset of women with chronic inflammation of the placenta. These findings provide insight into the immunology of the maternal-fetal interface in preterm and term labor.

Effector and Activated T Cells Induce Preterm Labor and Birth That Is Prevented by Treatment with Progesterone

Preterm labor commonly precedes preterm birth, the leading cause of perinatal morbidity and mortality worldwide. Most research has focused on establishing a causal link between innate immune activation and pathological inflammation leading to preterm labor and birth. However, the role of maternal effector/activated T cells in the pathogenesis of preterm labor/birth is poorly understood. In this study, we first demonstrated that effector memory and activated maternal T cells expressing granzyme B and perforin are enriched at the maternal-fetal interface (decidua) of women with spontaneous preterm labor. Next, using a murine model, we reported that prior to inducing preterm birth, in vivo T cell activation caused maternal hypothermia, bradycardia, systemic inflammation, cervical dilation, intra-amniotic inflammation, and fetal growth restriction, all of which are clinical signs associated with preterm labor. In vivo T cell activation also induced B cell cytokine responses, a proinflammatory macrophage polarization, and other inflammatory responses at the maternal-fetal interface and myometrium in the absence of an increased influx of neutrophils. Finally, we showed that treatment with progesterone can serve as a strategy to prevent preterm labor/birth and adverse neonatal outcomes by attenuating the proinflammatory responses at the maternal-fetal interface and cervix induced by T cell activation. Collectively, these findings provide mechanistic evidence showing that effector and activated T cells cause pathological inflammation at the maternal-fetal interface, in the mother, and in the fetus, inducing preterm labor and birth and adverse neonatal outcomes. Such adverse effects can be prevented by treatment with progesterone, a clinically approved strategy.

The role of maternal T cell and macrophage activation in preterm birth: Cause or consequence?

The role of the immune system in term (TL) and preterm labor (PTL) is unknown. Despite the fact that globally, PTL remains the most important cause of childhood mortality. Infection, typically of the fetal membranes, termed chorioamnionitis, is the best-understood driver of PTL, but the mechanisms underpinning other causes, including idiopathic and stretch-induced PTL, are unclear, but may well involve activation of the maternal immune system. The final common pathway of placental dysfunction, fetal membrane rupture, cervical dilation and uterine contractions are highly complex processes. At term, choriodecidual rather than myometrial inflammation is thought to drive the onset of labor and similar findings are present in different types of PTL including idiopathic PTL. Although accumulated data has confirmed an association between the immune response and preterm birth, there is yet a need to understand if this response is an initiator or a consequence of tissue-level dysregulation. This review focuses on the potential role of macrophages and T cells in innate and adaptive immunity relevant to preterm birth in humans and animal models.

Targeted expression profiling by RNA-Seq improves detection of cellular dynamics during pregnancy and identifies a role for T cells in term parturition

Development of maternal blood transcriptomic markers to monitor placental function and risk of obstetrical complications throughout pregnancy requires accurate quantification of gene expression. Herein, we benchmark three state-of-the-art expression profiling techniques to assess in maternal circulation the expression of cell type-specific gene sets previously discovered by single-cell genomics studies of the placenta. We compared Affymetrix Human Transcriptome Arrays, Illumina RNA-Seq, and sequencing-based targeted expression profiling (DriverMap^TM) to assess transcriptomic changes with gestational age and labor status at term, and tested 86 candidate genes by qRT-PCR. DriverMap identified twice as many significant genes (q < 0.1) than RNA-Seq and five times more than microarrays. The gap in the number of significant genes remained when testing only protein-coding genes detected by all platforms. qRT-PCR validation statistics (PPV and AUC) were high and similar among platforms, yet dynamic ranges were higher for sequencing based platforms than microarrays. DriverMap provided the strongest evidence for the association of B-cell and T-cell gene signatures with gestational age, while the T-cell expression was increased with spontaneous labor at term according to all three platforms. We concluded that sequencing-based techniques are more suitable to quantify whole-blood gene expression compared to microarrays, as they have an expanded dynamic range and identify more true positives. Targeted expression profiling achieved higher coverage of protein-coding genes with fewer total sequenced reads, and it is especially suited to track cell type-specific signatures discovered in the placenta. The T-cell gene expression signature was increased in women who underwent spontaneous labor at term, mimicking immunological processes at the maternal-fetal interface and placenta.

Chronic inflammatory lesions of the placenta are associated with an up-regulation of amniotic fluid CXCR3: A marker of allograft rejection

OBJECTIVE

The objective of this study is to determine whether the amniotic fluid (AF) concentration of soluble CXCR3 and its ligands CXCL9 and CXCL10 changes in patients whose placentas show evidence of chronic chorioamnionitis or other placental lesions consistent with maternal anti-fetal rejection.

METHODS

This retrospective case-control study included 425 women with (1) preterm delivery (n=92); (2) term in labor (n=68); and (3) term not in labor (n=265). Amniotic fluid CXCR3, CXCL9 and CXCL10 concentrations were determined by ELISA.

RESULTS

(1) Amniotic fluid concentrations of CXCR3 and its ligands CXCL9 and CXCL10 are higher in patients with preterm labor and maternal anti-fetal rejection lesions than in those without these lesions [CXCR3: preterm labor and delivery with maternal anti-fetal rejection placental lesions (median, 17.24 ng/mL; IQR, 6.79-26.68) vs. preterm labor and delivery without these placental lesions (median 8.79 ng/mL; IQR, 4.98-14.7; P=0.028)]; (2) patients with preterm labor and chronic chorioamnionitis had higher AF concentrations of CXCL9 and CXCL10, but not CXCR3, than those without this lesion [CXCR3: preterm labor with chronic chorioamnionitis (median, 17.02 ng/mL; IQR, 5.57-26.68) vs. preterm labor without chronic chorioamnionitis (median, 10.37 ng/mL; IQR 5.01-17.81; P=0.283)]; (3) patients with preterm labor had a significantly higher AF concentration of CXCR3 than those in labor at term regardless of the presence or absence of placental lesions.

CONCLUSION

Our findings support a role for maternal anti-fetal rejection in a subset of patients with preterm labor.

Differential Effect of Cytomegalovirus Infection with Age on the Expression of CD57, CD300a, and CD161 on T-Cell Subpopulations

Immunosenescence is a progressive deterioration of the immune system with aging. It affects both innate and adaptive immunity limiting the response to pathogens and to vaccines. As chronic cytomegalovirus (CMV) infection is probably one of the major driving forces of immunosenescence, and its persistent infection results in functional and phenotypic changes to the T-cell repertoire, the aim of this study was to analyze the effect of CMV-seropositivity and aging on the expression of CD300a and CD161 inhibitory receptors, along with the expression of CD57 marker on CD4⁺, CD8⁺, CD8⁺CD56⁺ (NKT-Like) and CD4⁻CD8⁻ (DN) T-cell subsets. Our results showed that, regardless of the T-cell subset, CD57⁻CD161⁻CD300a⁺ T-cells expand with age in CMV-seropositive individuals, whereas CD57⁻CD161⁺CD300a⁺ T-cells decrease. Similarly, CD57⁺CD161⁻CD300a⁺ T-cells expand with age in CMV-seropositive individuals in all subsets except in DN cells and CD57⁻CD161⁺CD300a⁻ T-cells decrease in all T-cell subsets except in CD4⁺ T-cells. Besides, in young individuals, CMV latent infection associates with the expansion of CD57⁺CD161⁻CD300a⁺CD4⁺, CD57⁻CD161⁻CD300a⁺CD4⁺, CD57⁺CD161⁻CD300a⁺CD8⁺, CD57⁻CD161⁻CD300a⁺CD8⁺, CD57⁺CD161⁻CD300a⁺NKT-like, and CD57⁺CD161⁻CD300a⁺DN T-cells. Moreover, in young individuals, CD161 expression on T-cells is not affected by CMV infection. Changes of CD161 expression were only associated with age in the context of CMV latent infection. Besides, CD300a⁺CD57⁺CD161⁺ and CD300a⁻CD57⁺CD161⁺ phenotypes were not found in any of the T-cell subsets studied except in the DN subpopulation, indicating that in the majority of T-cells, CD161 and CD57 do not co-express. Thus, our results show that CMV latent infection impact on the immune system depends on the age of the individual, highlighting the importance of including CMV serology in any study regarding immunosenescence.

Hepatitis A virus cellular receptor 2 (HAVCR2) is decreased with viral infection and regulates pro-labour mediators OA

PROBLEM

Intrauterine infection caused by viral infection has been implicated to contribute to preterm birth. Hepatitis A virus cellular receptor 2 (HAVCR2) regulates inflammation in non-gestational tissues in response to viral infection.

METHOD OF STUDY

The aims of this study were to determine the effect of: (i) viral dsRNA analogue polyinosinic:polycytidylic acid (poly(I:C)) on HAVCR2 expression; and (ii) HAVCR2 silencing by siRNA (siHAVCR2) in primary amnion and myometrial cells on poly(I:C)-induced inflammation.

RESULTS

In human foetal membranes and myometrium, HAVCR2 mRNA and protein expression was decreased when exposed to poly(I:C). Treatment of primary amnion and myometrial cells with poly(I:C) significantly increased the expression and release of pro-inflammatory cytokines TNF, IL1A, IL1B and IL6; the expression of chemokines CXCL8 and CCL2; the expression and secretion of adhesion molecules ICAM1 and VCAM1; and PTGS2 and PTGFR mRNA expression and the release of prostaglandin PGF_2α . This increase was significantly augmented in cells transfected with siHAVCR2. Furthermore, mRNA expression of anti-inflammatory cytokines IL4 and IL10 was significantly decreased.

CONCLUSION

Collectively, our data suggest that HAVCR2 regulates cytokines, chemokines, prostaglandins and cell adhesion molecules in the presence of viral infection. This suggests a potential for HAVCR2 activators as therapeutics for the management of preterm birth associated with viral infections.

In vivo T-cell activation by a monoclonal αCD3ε antibody induces preterm labor and birth

PROBLEM

Activated/effector T cells seem to play a role in the pathological inflammation associated with preterm labor. The aim of this study was to determine whether in vivo T-cell activation by a monoclonal αCD3ε antibody induces preterm labor and birth.

METHOD OF STUDY

Pregnant B6 mice were intraperitoneally injected with a monoclonal αCD3ε antibody or its isotype control. The gestational age, the rates of preterm birth and pup mortality at birth as well as the fetal heart rate and umbilical artery pulsatility index were determined.

RESULTS

Injection of a monoclonal αCD3ε antibody led to preterm labor/birth (αCD3ε 83 ± 16.97% [10/12] vs isotype 0% [0/8]) and increased the rate of pup mortality at birth (αCD3ε 87.30 ± 8.95% [77/85] vs isotype 4.91 ± 4.34% [3/59]). In addition, injection of a monoclonal αCD3ε antibody decreased the fetal heart rate and increased the umbilical artery pulsatility index when compared to the isotype control.

CONCLUSION

In vivo T-cell activation by a monoclonal αCD3ε antibody in late gestation induces preterm labor and birth.

The expression and function of human CD300 receptors on blood circulating mononuclear cells are distinct in neonates and adults

Neonates are more susceptible to infections than adults. This susceptibility is thought to reflect neonates' qualitative and quantitative defects in the adaptive and innate immune responses. Differential expression of cell surface receptors may result in altered thresholds of neonatal immune cell activation. We determined whether the expression and function of the lipid-binding CD300 family of receptors are different on neonatal immune cells compared to adult immune cells. A multiparametric flow cytometry analysis was performed to determine the expression of CD300 receptors on adult peripheral blood mononuclear cells and neonatal cord blood mononuclear cells. The expression of the CD300a inhibitory receptor was significantly reduced on cells from the newborn adaptive immune system, and neonatal antigen presenting cells exhibited a different CD300 receptors expression pattern. We also found differential LPS-mediated regulation of CD300 receptors expression on adult monocytes compared to cord blood monocytes, and that CD300c and CD300e-mediated activation was quantitatively different in neonatal monocytes. This is the first complete study examining the expression of CD300 receptors on human neonatal immune cells compared with adult immune cells. Significant differences in the expression and function of CD300 receptors may help to explain the peculiarities and distinctness of the neonatal immune responses.

An M1-like Macrophage Polarization in Decidual Tissue during Spontaneous Preterm Labor That Is Attenuated by Rosiglitazone Treatment

Decidual macrophages are implicated in the local inflammatory response that accompanies spontaneous preterm labor/birth; however, their role is poorly understood. We hypothesized that decidual macrophages undergo a proinflammatory (M1) polarization during spontaneous preterm labor and that PPARγ activation via rosiglitazone (RSG) would attenuate the macrophage-mediated inflammatory response, preventing preterm birth. In this study, we show that: 1) decidual macrophages undergo an M1-like polarization during spontaneous term and preterm labor; 2) anti-inflammatory (M2)-like macrophages are more abundant than M1-like macrophages in decidual tissue; 3) decidual M2-like macrophages are reduced in preterm pregnancies compared with term pregnancies, regardless of the presence of labor; 4) decidual macrophages express high levels of TNF and IL-12 but low levels of peroxisome proliferator-activated receptor γ (PPARγ) during spontaneous preterm labor; 5) decidual macrophages from women who underwent spontaneous preterm labor display plasticity by M1↔M2 polarization in vitro; 6) incubation with RSG reduces the expression of TNF and IL-12 in decidual macrophages from women who underwent spontaneous preterm labor; and 7) treatment with RSG reduces the rate of LPS-induced preterm birth and improves neonatal outcomes by reducing the systemic proinflammatory response and downregulating mRNA and protein expression of NF-κB, TNF, and IL-10 in decidual and myometrial macrophages in C57BL/6J mice. In summary, we demonstrated that decidual M1-like macrophages are associated with spontaneous preterm labor and that PPARγ activation via RSG can attenuate the macrophage-mediated proinflammatory response, preventing preterm birth and improving neonatal outcomes. These findings suggest that the PPARγ pathway is a new molecular target for future preventative strategies for spontaneous preterm labor/birth.

Vaginal progesterone, but not 17α-hydroxyprogesterone caproate, has antiinflammatory effects at the murine maternal-fetal interface

OBJECTIVE

Progestogen (vaginal progesterone or 17-alpha-hydroxyprogesterone caproate [17OHP-C]) administration to patients at risk for preterm delivery is widely used for the prevention of preterm birth (PTB). The mechanisms by which these agents prevent PTB are poorly understood. Progestogens have immunomodulatory functions; therefore, we investigated the local effects of vaginal progesterone and 17OHP-C on adaptive and innate immune cells implicated in the process of parturition.

STUDY DESIGN

Pregnant C57BL/6 mice received vaginal progesterone (1 mg per 200 μL, n = 10) or Replens (control, 200 μL, n = 10) from 13 to 17 days postcoitum (dpc) or were subcutaneously injected with 17OHP-C (2 mg per 100 μL, n = 10) or castor oil (control, 100 μL, n = 10) on 13, 15, and 17 dpc. Decidual and myometrial leukocytes were isolated prior to term delivery (18.5 dpc) for immunophenotyping by flow cytometry. Cervical tissue samples were collected to determine matrix metalloproteinase (MMP)-9 activity by in situ zymography and visualization of collagen content by Masson's trichrome staining. Plasma concentrations of progesterone, estradiol, and cytokines (interferon [IFN]γ, interleukin (IL)-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12p70, keratinocyte-activated chemokine/growth-related oncogene, and tumor necrosis factor-α) were quantified by enzyme-linked immunosorbent assays. Pregnant mice pretreated with vaginal progesterone or Replens were injected with 10 μg of an endotoxin on 16.5 dpc (n = 10 each) and monitored via infrared camera until delivery to determine the effect of vaginal progesterone on the rate of PTB.

RESULTS

The following results were found: (1) vaginal progesterone, but not 17OHP-C, increased the proportion of decidual CD4+ regulatory T cells; (2) vaginal progesterone, but not 17OHP-C, decreased the proportion of decidual CD8+CD25+Foxp3+ T cells and macrophages; (3) vaginal progesterone did not result in M1→M2 macrophage polarization but reduced the proportion of myometrial IFNγ+ neutrophils and cervical active MMP-9-positive neutrophils and monocytes; (4) 17OHP-C did not reduce the proportion of myometrial IFNγ+ neutrophils; however, it increased the abundance of cervical active MMP-9-positive neutrophils and monocytes; (5) vaginal progesterone immune effects were associated with reduced systemic concentrations of IL-1β but not with alterations in progesterone or estradiol concentrations; and (6) vaginal progesterone pretreatment protected against endotoxin-induced PTB (effect size 50%, P = 0.011).

CONCLUSION

Vaginal progesterone, but not 17OHP-C, has local antiinflammatory effects at the maternal-fetal interface and the cervix and protects against endotoxin-induced PTB.

Chronic inflammation of the placenta: definition, classification, pathogenesis, and clinical significance

Chronic inflammatory lesions of the placenta are characterized by the infiltration of the organ by lymphocytes, plasma cells, and/or macrophages and may result from infections (viral, bacterial, parasitic) or be of immune origin (maternal anti-fetal rejection). The 3 major lesions are villitis (when the inflammatory process affects the villous tree), chronic chorioamnionitis (which affects the chorioamniotic membranes), and chronic deciduitis (which involves the decidua basalis). Maternal cellular infiltration is a common feature of the lesions. Villitis of unknown etiology (VUE) is a destructive villous inflammatory lesion that is characterized by the infiltration of maternal T cells (CD8+ cytotoxic T cells) into chorionic villi. Migration of maternal T cells into the villi is driven by the production of T-cell chemokines in the affected villi. Activation of macrophages in the villi has been implicated in the destruction of the villous architecture. VUE has been reported in association with preterm and term fetal growth restriction, preeclampsia, fetal death, and preterm labor. Infants whose placentas have VUE are at risk for death and abnormal neurodevelopmental outcome at the age of 2 years. Chronic chorioamnionitis is the most common lesion in late spontaneous preterm birth and is characterized by the infiltration of maternal CD8+ T cells into the chorioamniotic membranes. These cytotoxic T cells can induce trophoblast apoptosis and damage the fetal membranes. The lesion frequently is accompanied by VUE. Chronic deciduitis consists of the presence of lymphocytes or plasma cells in the basal plate of the placenta. This lesion is more common in pregnancies that result from egg donation and has been reported in a subset of patients with premature labor. Chronic placental inflammatory lesions can be due to maternal anti-fetal rejection, a process associated with the development of a novel form of fetal systemic inflammatory response. The syndrome is characterized by an elevation of the fetal plasma T-cell chemokine. The evidence that maternal anti-fetal rejection underlies the pathogenesis of many chronic inflammatory lesions of the placenta is reviewed. This article includes figures and histologic examples of all chronic inflammatory lesions of the placenta.

The Biology and Disease Relevance of CD300a, an Inhibitory Receptor for Phosphatidylserine and Phosphatidylethanolamine

The CD300a inhibitory receptor belongs to the CD300 family of cell surface molecules that regulate a diverse array of immune cell processes. The inhibitory signal of CD300a depends on the phosphorylation of tyrosine residues embedded in ITIMs of the cytoplasmic tail. CD300a is broadly expressed on myeloid and lymphoid cells, and its expression is differentially regulated depending on the cell type. The finding that CD300a recognizes phosphatidylserine and phosphatidylethanolamine, two aminophospholipids exposed on the outer leaflet of dead and activated cells, has shed new light on its role in the modulation of immune functions and in its participation in the host response to several diseases states, such as infectious diseases, cancer, allergy, and chronic inflammatory diseases. This review summarizes the literature on CD300a expression, regulation, signaling pathways, and ligand interaction, as well as its role in fine tuning immune cell functions and its clinical relevance.

Galectins: Double-edged Swords in the Cross-roads of Pregnancy Complications and Female Reproductive Tract Inflammation and Neoplasia

Galectins are an evolutionarily ancient and widely expressed family of lectins that have unique glycan-binding characteristics. They are pleiotropic regulators of key biological processes, such as cell growth, proliferation, differentiation, apoptosis, signal transduction, and pre-mRNA splicing, as well as homo- and heterotypic cell-cell and cell-extracellular matrix interactions. Galectins are also pivotal in immune responses since they regulate host-pathogen interactions, innate and adaptive immune responses, acute and chronic inflammation, and immune tolerance. Some galectins are also central to the regulation of angiogenesis, cell migration and invasion. Expression and functional data provide convincing evidence that, due to these functions, galectins play key roles in shared and unique pathways of normal embryonic and placental development as well as oncodevelopmental processes in tumorigenesis. Therefore, galectins may sometimes act as double-edged swords since they have beneficial but also harmful effects for the organism. Recent advances facilitate the use of galectins as biomarkers in obstetrical syndromes and in various malignancies, and their therapeutic applications are also under investigation. This review provides a general overview of galectins and a focused review of this lectin subfamily in the context of inflammation, infection and tumors of the female reproductive tract as well as in normal pregnancies and those complicated by the great obstetrical syndromes.

Placental lesions associated with acute atherosis

OBJECTIVE

Acute atherosis is a lesion of the spiral arteries characterized by fibrinoid necrosis of the vessel wall, an accumulation of fat-containing macrophages, and a mononuclear perivascular infiltrate, which can be found in patients with preeclampsia, fetal death, small-for-gestational age, spontaneous preterm labor/premature prelabor rupture of membrane, and spontaneous mid-trimester abortion. This lesion is thought to decrease blood flow to the intervillous space which may lead to other vascular lesions of the placenta. The objective of this study was to test whether there is an association between acute atherosis and placental lesions that are consistent with maternal vascular underperfusion (MVU), amniotic fluid infection (AFI), fetal vascular thrombo-occlusive disease (FVTOD) or chronic inflammation.

MATERIAL AND METHODS

A retrospective cohort study of pregnant women who delivered between July 1998 and July 2014 at Hutzel Women's Hospital/Detroit Medical Center was conducted examine 16 457 placentas. The frequency of placenta lesions (diagnosed using the criteria of the Perinatal Section of the Society for Pediatric Pathology) was compared between pregnancies with and without acute atherosis.

RESULTS

Among 16 457 women who were enrolled, 10.2% (1671/16 457) were excluded, leaving 14 786 women who contributed data for analysis. Among them, the prevalence of acute atherosis was 2.2% (326/14 786). Women with acute atherosis were more than six times as likely as those without to have placental lesions consistent with maternal underperfusion (adjusted odds ratio - aOR: 6.7; 95% CI 5.2-8.6). To a lesser degree, acute atherosis was also associated with greater risks of having either lesions consistent with FVTOD (aOR 1.7; 95% CI 1.2-2.3) or chronic chorioamnionitis (aOR 1.9; 95% CI 1.3-3), but not with other chronic inflammatory lesions, after adjusting for gestational age at delivery. In contrast, women with acute atherosis were 60% less likely to have lesions consistent with AFI, adjusting for gestational age at delivery (aOR 0.4; 95% CI 0.3-0.5).

CONCLUSIONS

Acute atherosis is associated with increased risks of having placental lesions consistent with MVU, and to a lesser extent, chronic chorioamnionitis and those consistent with FVTOD.

Phosphatidylserine receptors: enhancers of enveloped virus entry and infection

A variety of both RNA and DNA viruses envelop their capsids in a lipid bilayer. One of the more recently appreciated benefits this envelope is incorporation of phosphatidylserine (PtdSer). Surface exposure of PtdSer disguises viruses as apoptotic bodies; tricking cells into engulfing virions. This mechanism is termed apoptotic mimicry. Several PtdSer receptors have been identified to enhance virus entry and we have termed this group of proteins PtdSer-mediated virus entry enhancing receptors or PVEERs. These receptors enhance entry of a range of enveloped viruses. Internalization of virions by PVEERs provides a broad mechanism of entry with little investment by the virus itself. PVEERs may allow some viruses to attach to cells, thereby making viral glycoprotein/cellular receptor interactions more probable. Alternatively, other viruses may rely entirely on PVEERs for internalization into endosomes. This review provides an overview of PtdSer receptors that serve as PVEERs and the biology behind virion/PVEER interaction.

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Phosphatidylserine (PtdSer) receptors can mediate entry of enveloped viruses.

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PtdSer is present on the outer leaflet of the virion envelope.

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PtdSer receptors are expressed on a variety of primary cells and cell lines.

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Characteristics of PtdSer receptors that mediate virus entry are defined.

Immune cells in term and preterm labor

Labor resembles an inflammatory response that includes secretion of cytokines/chemokines by resident and infiltrating immune cells into reproductive tissues and the maternal/fetal interface. Untimely activation of these inflammatory pathways leads to preterm labor, which can result in preterm birth. Preterm birth is a major determinant of neonatal mortality and morbidity; therefore, the elucidation of the process of labor at a cellular and molecular level is essential for understanding the pathophysiology of preterm labor. Here, we summarize the role of innate and adaptive immune cells in the physiological or pathological activation of labor. We review published literature regarding the role of innate and adaptive immune cells in the cervix, myometrium, fetal membranes, decidua and the fetus in late pregnancy and labor at term and preterm. Accumulating evidence suggests that innate immune cells (neutrophils, macrophages and mast cells) mediate the process of labor by releasing pro-inflammatory factors such as cytokines, chemokines and matrix metalloproteinases. Adaptive immune cells (T-cell subsets and B cells) participate in the maintenance of fetomaternal tolerance during pregnancy, and an alteration in their function or abundance may lead to labor at term or preterm. Also, immune cells that bridge the innate and adaptive immune systems (natural killer T (NKT) cells and dendritic cells (DCs)) seem to participate in the pathophysiology of preterm labor. In conclusion, a balance between innate and adaptive immune cells is required in order to sustain pregnancy; an alteration of this balance will lead to labor at term or preterm.

Infection and smoking are associated with decreased plasma concentration of the anti-aging protein, α-klotho

OBJECTIVE

The objective of this study was to determine whether maternal plasma concentrations of soluble α-klotho are different between women with microbial invasion of the intra-amniotic cavity (MIAC) and those without MIAC among preterm labor and intact membranes (PTL) or preterm prelabor rupture of membranes (pPROM).

METHODS

A cross-sectional study was conducted to include women in the following groups: i) PTL with MIAC (n=14); ii) PTL without MIAC (n=79); iii) pPROM with MIAC (n=30); and iv) pPROM without MIAC (n=33). MIAC was defined as a positive amniotic fluid culture for microorganisms (aerobic/anaerobic bacteria or genital mycoplasmas). Amniotic fluid samples were obtained within 48 h of maternal blood collection. Plasma concentration of soluble α-klotho was determined by ELISA.

RESULTS

i) The median plasma concentration (pg/mL) of soluble α-klotho was significantly lower in patients with MIAC than in those without MIAC (787.0 vs. 1117.8; P<0.001). ii) Among patients with PTL, those with MIAC had a lower median plasma concentration (pg/mL) of soluble α-klotho than those without MIAC (787.0 vs. 1138.9; P=0.007). iii) Among patients with pPROM, those with MIAC had a lower median plasma concentration (pg/mL) of soluble α-klotho than those without MIAC (766.4 vs. 1001.6; P=0.045). iv) There was no significant difference in the median plasma concentration of soluble α-klotho between PPROM without MIAC and PTL without MIAC (1001.6 pg/mL vs. 1138.9 pg/mL, respectively; P=0.5). v) After adjustment for potential confounders (maternal age, tobacco use, gestational age at venipuncture), soluble α-klotho remained significantly associated with MIAC (P=0.02); and vi) Among patients without MIAC, smoking was significantly associated with a lower median plasma concentration soluble α-klotho than in non-smokers (794.2 pg/mL vs. 1382.0 pg/mL, respectively; P<0.001); however, this difference was not observed in patients with MIAC.

CONCLUSIONS

Intra-amniotic infection occurring at preterm gestations (regardless of membrane status) was associated with a decrease in maternal plasma concentrations of soluble α-klotho. Moreover, among patients without infection, the plasma concentration of α-klotho was lower in smokers.

Maternal floor infarction/massive perivillous fibrin deposition: a manifestation of maternal antifetal rejection?

OBJECTIVE

Massive perivillous fibrin deposition (MPFD) and maternal floor infarction (MFI) are related placental lesions often associated with fetal death and fetal growth restriction. A tendency to recur in subsequent pregnancies has been reported. This study was conducted to determine whether this complication of pregnancy could reflect maternal antifetal rejection.

METHODS

Pregnancies with MPFD were identified (n = 10). Controls consisted of women with uncomplicated pregnancies who delivered at term without MPFD (n = 175). Second-trimester maternal plasma was analyzed for panel-reactive anti-HLA class I and class II antibodies. The prevalence of chronic chorioamnionitis, villitis of unknown etiology, and plasma cell deciduitis was compared between cases and controls. Immunohistochemistry was performed on available umbilical vein segments from cases with MPFD (n = 4) to determine whether there was evidence of complement activation (C4d deposition). Specific maternal HLA-antibody and fetal HLA-antigen status were also determined in paired specimens (n = 6). Plasma CXCL-10 concentrations were measured in longitudinal samples of cases (n = 28 specimens) and controls (n = 749 specimens) by ELISA. Linear mixed-effects models were used to test for differences in plasma CXCL-10 concentration.

RESULTS

(i) The prevalence of plasma cell deciduitis in the placenta was significantly higher in cases with MPFD than in those with uncomplicated term deliveries (40% versus 8.6%, P = 0.01), (ii) patients with MPFD had a significantly higher frequency of maternal anti-HLA class I positivity during the second trimester than those with uncomplicated term deliveries (80% versus 36%, P = 0.01); (iii) strongly positive C4d deposition was observed on umbilical vein endothelium in cases of MPFD, (iv) a specific maternal antibody against fetal HLA antigen class I or II was identified in all cases of MPFD; and 5) the mean maternal plasma concentration of CXCL-10 was higher in patients with evidence of MPFD than in those without evidence of MFPD (P < 0.001).

CONCLUSION

A subset of patients with MPFD has evidence of maternal antifetal rejection.

Viral infection of the pregnant cervix predisposes to ascending bacterial infection

Preterm birth is the major cause of neonatal mortality and morbidity, and bacterial infections that ascend from the lower female reproductive tract are the most common route of uterine infection leading to preterm birth. The uterus and growing fetus are protected from ascending infection by the cervix, which controls and limits microbial access by the production of mucus, cytokines, and antimicrobial peptides. If this barrier is compromised, bacteria may enter the uterine cavity, leading to preterm birth. Using a mouse model, we demonstrate, to our knowledge for the first time, that viral infection of the cervix during pregnancy reduces the capacity of the female reproductive tract to prevent bacterial infection of the uterus. This is due to differences in susceptibility of the cervix to infection by virus during pregnancy and the associated changes in TLR and antimicrobial peptide expression and function. We suggest that preterm labor is a polymicrobial disease, which requires a multifactorial approach for its prevention and treatment.

Evidence for a role for the adaptive immune response in human term parturition

PROBLEM

Spontaneous labor at term involves leukocyte recruitment and infiltration into the choriodecidua; yet, characterization of these leukocytes and their immunological mediators is incomplete. The purpose of this study was to characterize the immunophenotype of choriodecidual leukocytes as well as the expression of inflammatory mediators in human spontaneous parturition at term.

METHOD OF STUDY

Choriodecidual leukocytes were analyzed by FACS, immunohistochemistry, and RT-PCR in three different groups: (i) preterm gestation delivered for medical indications without labor; (ii) term pregnancy without labor; and (iii) term pregnancy after spontaneous labor.

RESULTS

Two T-cell subsets of memory-like T cells (CD3(+) CD4(+) CD45RO(+) and CD3(+) CD4(-) CD8(-) CD45RO(+) cells) were identified in the choriodecidua of women who had spontaneous labor. Evidence for an extensive immune signaling network composed of chemokines (CXCL8 and CXCL10), chemokine receptors (CXCR1-3), cytokines (IL-1β and TNF-α), cell adhesion molecules, and MMP-9 was identified in these cells during spontaneous labor at term.

CONCLUSIONS

The influx of memory-like T cells in the choriodecidua and the evidence that they are active by producing chemokines and cytokines, and expressing chemokine receptors, cell adhesion molecules, and a matrix-degrading enzyme provides support for the participation of the adaptive immune system in the mechanisms of spontaneous parturition at term.

Identification of intracellular bacteria in the basal plate of the human placenta in term and preterm gestations

OBJECTIVE

Bacteria have been identified in different regions of the placenta. Here, we tested the hypothesis that the maternal basal plate of the placenta harbors microbes that may be associated with adverse pregnancy outcomes.

STUDY DESIGN

We performed a cross-sectional study of pregnancies from a single tertiary care hospital. Maternal medical and obstetric characteristics were obtained and pregnancies followed up prospectively for outcomes and placental collection. After delivery, systematic random sampling of the placental basal plate was performed. Paraffin sections of basal plates were stained with 4 histologic stains and scored for morphological evidence of bacteria.

RESULTS

Of 195 total patients in the study, Gram-positive and -negative intracellular bacteria of diverse morphologies were documented in the basal plates of 27% of all placentas. Of the patients, 35% delivered preterm. No difference was noted between placental basal plates from preterm or term gestations. Intracellular bacteria were found in the placental basal plates of 54% spontaneous preterm deliveries <28 weeks, and in 26% of term spontaneous deliveries (P = .02). Intracellular bacteria were also documented in placentas without clinical or pathologic chorioamnionitis.

CONCLUSION

A total of 27% of placentas demonstrated intracellular bacteria in the placental basal plate using morphological techniques. Thus, the maternal basal plate is a possible source of intrauterine colonization and placental pathological examination could include examination for bacteria in this important maternal-fetal interface.

Interleukin-33 in the human placenta

OBJECTIVE

Interleukin-33 (IL-33) is the newest member of the IL-1 cytokine family, a group of key regulators of inflammation. The purpose of this study was to determine whether IL-33 is expressed in the human placenta and to investigate its expression in the context of acute and chronic chorioamnionitis.

METHODS

Placental tissues were obtained from five groups of patients: 1) normal pregnancy at term without labor (n = 10); 2) normal pregnancy at term in labor (n = 10); 3) preterm labor without inflammation (n = 10); 4) preterm labor with acute chorioamnionitis and funisitis (n = 10); and 5) preterm labor with chronic chorioamnionitis (n = 10). Immunostaining was performed to determine IL-33 protein expression patterns in the placental disk, chorioamniotic membranes, and umbilical cord. mRNA expression of IL-33 and its receptor IL1RL1 (ST2) was measured in primary amnion epithelial and mesenchymal cells (AECs and AMCs, n = 4) and human umbilical vein endothelial cells (HUVECs, n = 4) treated with IL-1β (1 and 10 ng/ml) and CXCL10 (0.5 and 1 or 5 ng/ml).

RESULTS

1) Nuclear IL-33 expression was found in endothelial and smooth muscle cells in the placenta, chorioamniotic membranes, and umbilical cord; 2) IL-33 was detected in the nucleus of CD14+ macrophages in the chorioamniotic membranes, chorionic plate, and umbilical cord, and in the cytoplasm of myofibroblasts in the Wharton's jelly; 3) acute (but not chronic) chorioamnionitis was associated with the presence of IL-33+ macrophages in the chorioamniotic membranes and umbilical cord; 4) expression of IL-33 or IL1RL1 (ST2) mRNA in AECs was undetectable; 5) IL-33 mRNA expression increased in AMCs and HUVECs after IL-1β treatment but did not change with CXCL10 treatment; and 6) IL1RL1 (ST2) expression decreased in AMCs and increased in HUVECs after IL-1β but not CXCL10 treatment.

CONCLUSIONS

IL-33 is expressed in the nucleus of placental endothelial cells, CD14+ macrophages, and myofibroblasts in the Wharton's jelly. IL-1β can induce the expression of IL-33 and its receptor. Protein expression of IL-33 is detectable in macrophages of the chorioamniotic membranes in acute (but not chronic) chorioamnionitis.

The CD300 molecules: an emerging family of regulators of the immune system

The CD300 family of molecules modulates a broad and diverse array of immune cell processes via their paired activating and inhibitory receptor functions. The description that CD300 molecules are able to recognize lipids, such as extracellular ceramide, phosphatidylserine, and phosphatidylethanolamine, that are exposed on the outer leaflet of the plasma membrane of dead and activated cells has opened a new field of research. Through their binding to lipids and other ligands, this family of receptors is poised to have a significant role in complex biological processes and in the host response to severe pathological conditions. Indeed, published data have demonstrated their participation in the pathogenesis of several disease states. Moreover, this family of receptors has great potential as targets for diagnosis and therapeutic purposes in infectious diseases, allergies, cancer, and other pathological situations. For instance, one member of the family, CD300a, has been studied as a possible biomarker. Here, a review is provided on the cellular distribution of the human and mouse families of receptors, the stimuli that regulate their expression, their ability to tune leukocyte function and immune responses, their signaling pathways, ligand recognition, and their clinical relevance.

A blueprint for the prevention of preterm birth: vaginal progesterone in women with a short cervix

Preterm birth is the leading cause of perinatal morbidity and mortality worldwide, and is the most important challenge to modern obstetrics. A major obstacle has been that preterm birth is treated (implicitly or explicitly) as a single condition. Two thirds of preterm births occur after the spontaneous onset of labor, and the remaining one third after "indicated" preterm birth; however, the causes of spontaneous preterm labor and "indicated" preterm birth are different. Spontaneous preterm birth is a syndrome caused by multiple etiologies, one of which is a decline in progesterone action, which induces cervical ripening. A sonographic short cervix (identified in the midtrimester) is a powerful predictor of spontaneous preterm delivery. Randomized clinical trials and individual patient meta-analyses have shown that vaginal progesterone reduces the rate of preterm delivery at <33 weeks of gestation by 44%, along with the rate of admission to the neonatal intensive care unit, respiratory distress syndrome, requirement for mechanical ventilation, and composite neonatal morbidity/mortality score. There is no evidence that 17-α-hydroxyprogesterone caproate can reduce the rate of preterm delivery in women with a short cervix, and therefore, the compound of choice is natural progesterone (not the synthetic progestin). Routine assessment of the risk of preterm birth with cervical ultrasound coupled with vaginal progesterone for women with a short cervix is cost-effective, and the implementation of such a policy is urgently needed. Vaginal progesterone is as effective as cervical cerclage in reducing the rate of preterm delivery in women with a singleton gestation, history of preterm birth, and a short cervix (<25 mm).

CD300 molecule regulation of human dendritic cell functions

Dendritic cells (DC) are a heterogeneous population of leucocytes which play a key role in initiating and modulating immune responses. The human CD300 family consists of six immunoregulatory leucocyte membrane molecules that regulate cellular activity including differentiation, viability, cytokine and chemokine secretion, phagocytosis and chemotaxis. Recent work has identified polar lipids as probable ligands for these molecules in keeping with the known evolutionary conservation of this family. CD300 molecules are all expressed by DC; CD300b, d, e and f are restricted to different subpopulations of the myeloid DC lineage. They have been shown to regulate DC function both in vitro and in vivo. In addition DC are able to regulate their CD300 expression in an autocrine manner. The potential to form different CD300 heterodimers adds further complexity to their role in fine tuning DC function. Expression of CD300 molecules is altered in a number of diseases including many where DC are implicated in the pathogenesis. CD300 antibodies have been demonstrated to have significant therapeutic effect in animal models. The mechanisms underlying the immunoregulatory effects of the CD300 family are complex. Deciphering their physiology will allow effective targeting of these molecules as novel therapies in a wide variety of inflammatory diseases.

Midtrimester amniotic fluid concentrations of interleukin-6 and interferon-gamma-inducible protein-10: evidence for heterogeneity of intra-amniotic inflammation and associations with spontaneous early (<32 weeks) and late (>32 weeks) preterm delivery

INTRODUCTION

Intra-amniotic inflammation is traditionally defined as an elevation of amniotic fluid interleukin (IL)-6. Previous case control studies have suggested an association between an elevated midtrimester amniotic fluid IL-6 and preterm delivery, although such an association has been recently challenged. Intra-amniotic inflammation can also be defined by an elevation of the T-cell chemokine, Interferon-gamma-inducible protein (IP)-10. An elevation in amniotic fluid IP-10 has been associated with chronic chorioamnionitis, a lesion frequently found in late spontaneous preterm birth and fetal death. In contrast, an elevation in amniotic fluid IL-6 is typically associated with acute chorioamnionitis and funisitis. This study was conducted to examine the relationship between an elevation in amniotic fluid IL-6 in the midtrimester and preterm delivery at or before 32 weeks of gestation, and the amniotic fluid concentration of IP-10 and preterm delivery after 32 weeks of gestation.

MATERIALS AND METHODS

This cohort study included 847 consecutive women undergoing genetic midtrimester amniocentesis; in 796 cases, amniotic fluid and pregnancy outcome was available for study after exclusion of abnormal karyotype and/or fetal congenital anomalies. Spontaneous preterm delivery was defined as early (≤32 weeks) or late (after 32 completed weeks of pregnancy). The amniotic fluid and maternal blood concentrations of IL-6 and IP-10 were measured by specific immunoassays.

RESULTS

1) The prevalence of preterm delivery was 8.3% (66/796), while those of early and late spontaneous preterm delivery were 1.5% (n=12), and 4.5% (n=36), respectively; 2) patients who had a spontaneous preterm delivery after 32 weeks of gestation had a higher median amniotic fluid IP-10 concentration than those who delivered at term [median 713 pg/mL, inter-quartile range (IQR) 509-1427 pg/mL vs. median 589 pg/mL, IQR 402-953 pg/mL; P=0.006] and an elevation of amniotic fluid IP-10 concentration above 502 pg/mL (derived from an ROC curve) was associated with late spontaneous preterm delivery [odds ratio 3.9 (95% CI 1.6-9.9)]; 3) patients who had a spontaneous preterm delivery ≤32 weeks of gestation had a higher median amniotic fluid IL-6 concentration than those who delivered at term [median 2052 pg/mL, IQR 435-3015 pg/mL vs. median 414 pg/mL, IQR 209-930 pg/mL; P=0.006], and an elevated amniotic fluid IL-6 concentration above 1740 pg/mL (derived from an ROC curve) was associated with early spontaneous preterm delivery [odds ratio 9.5 (95% CI 2.9-31.1)]; 4) subclinical intra-amniotic inflammation, defined as an elevation of IL-6 (≥2.9 ng/mL) or IP-10 (≥2.2 ng/mL) concentration above the 95th percentile of patients who had uncomplicated term delivery (n=652 for IL-6 and n=633 for IP-10), was observed in 6.3% (50/796) and 5.8% (45/770) of cases, respectively. Although each type of inflammation is a risk factor for spontaneous preterm delivery, many patients had a term delivery without complication; 5) the amniotic fluid in the midtrimester did not contain microorganisms detectable with cultivation techniques.

CONCLUSIONS

INTRA-amniotic inflammation is heterogeneous. Some patients have elevated amniotic fluid concentrations of IL-6, and are at risk for spontaneous preterm delivery before 32 weeks of gestation, while others have an elevated IP-10 (a chemotactic T-cell chemokine) and such patients are at risk for spontaneous preterm delivery after 32 weeks of gestation. A fraction of patients have subclinical intra-amniotic inflammation and deliver at term. The clinical significance of this condition remains to be determined.