Pharmacological blockade of the interleukin-1 receptor suppressed Escherichia coli lipopolysaccharide-induced neuroinflammation in preterm fetal sheep

BACKGROUND

Intraamniotic inflammation is associated with preterm birth, especially in cases occurring before 32 weeks' gestation, and is causally linked with an increased risk for neonatal mortality and morbidity. Targeted anti-inflammatory interventions may assist in improving the outcomes for pregnancies impacted by intrauterine inflammation. Interleukin-1 is a central upstream mediator of inflammation. Accordingly, interleukin-1 is a promising candidate target for intervention therapies and has been targeted previously using the interleukin-1 receptor antagonist, anakinra. Recent studies have shown that the novel, noncompetitive, allosteric interleukin-1 receptor inhibitor, rytvela, partially resolved inflammation associated with preterm birth and fetal injury. In this study, we used a preterm sheep model of chorioamnionitis to investigate the anti-inflammatory efficacy of rytvela and anakinra, administered in the amniotic fluid in the setting of intraamniotic Escherichia coli lipopolysaccharide exposure.

OBJECTIVE

We hypothesized that both rytvela and anakinra would reduce lipopolysaccharide-induced intrauterine inflammation and protect the fetal brain.

STUDY DESIGN

Ewes with a singleton fetus at 105 days of gestation (term is ∼150 days) were randomized to one of the following groups: (1) intraamniotic injections of 2 mL saline at time=0 and time=24 hours as a negative control group (saline group, n=12); (2) intraamniotic injection of 10 mg Escherichia coli lipopolysaccharide in 2 mL saline and intraamniotic injections of 2 mL saline at time=0 hours and time=24 hours as an inflammation positive control group (lipopolysaccharide group, n=11); (3) intraamniotic injection of Escherichia coli lipopolysaccharide in 2 mL saline and intraamniotic injections of 2.5 mg rytvela at time=0 hours and time=24 hours to test the anti-inflammatory efficacy of rytvela (lipopolysaccharide + rytvela group, n=10); or (4) intraamniotic injection of Escherichia coli lipopolysaccharide in 2 mL saline and intraamniotic injections of 100 mg anakinra at time=0 hours and time=24 hours to test the anti-inflammatory efficacy of anakinra (lipopolysaccharide + anakinra group, n=12). Amniotic fluid was sampled at time 0, 24, and 48 hours (ie, at each intervention and at delivery). Fetal umbilical cord blood was collected at delivery for differential blood counts and chemical studies. Inflammation was characterized by the analysis of fetal tissue cytokine and chemokine levels using quantitative polymerase chain reaction, enzyme-linked inmmunosorbent assay, and histology. The primary study outcome of interest was the assessment of anakinra and rytvela brain-protective effects in the setting of Escherichia coli lipopolysaccharide-induced intrauterine inflammation. Secondary outcomes of interest were to assess protection from fetal and intrauterine (ie, amniotic fluid, chorioamnion) inflammation.

RESULTS

Intraamniotic administration of lipopolysaccharide caused inflammation of the fetal lung, brain, and chorioamnionitis in preterm fetal sheep. Relative to treatment with saline only in the setting of lipopolysaccharide exposure, intraamniotic administration of both rytvela and anakinra both significantly prevented periventricular white matter injury, microglial activation, and histologic chorioamnionitis. Anakinra showed additional efficacy in inhibiting fetal lung myeloperoxidase activity, but its use was associated with metabolic acidaemia and reduced fetal plasma insulin-like growth factor-1 levels at delivery.

CONCLUSION

Intraamniotic administration of rytvela or anakinra significantly inhibited fetal brain inflammation and chorioamnionitis in preterm fetal sheep exposed to intraamniotic lipopolysaccharide. In addition, anakinra treatment was associated with potential negative impacts on the developing fetus.

Antibody microarray analysis of amniotic fluid proteomes in women with cervical insufficiency and short cervix, and their association with pregnancy latency length

Introduction

This study aimed to investigate amniotic fluid (AF) proteins that were differentially expressed between patients with cervical insufficiency (CI) and asymptomatic short cervix (SCX, ≤ 25 mm), and whether these proteins could be predictive of spontaneous preterm birth (SPTB) in these patients.

Method

This was a retrospective cohort study of 129 singleton pregnant women with CI (n = 80) or SCX (n = 49) at 17 to 26 weeks who underwent amniocentesis. An antibody microarray was used to perform comparative proteomic profiling of AF from matched CI (n = 20) and SCX (n = 20) pregnancies. In the total cohort, an ELISA validation study was performed for 15 candidate proteins of interest. Subgroup analyses of patients with CI and SCX were conducted to evaluate the association between the 15 proteins and SPTB at < 32 weeks of gestation.

Results

Eighty-six proteins showed intergroup differences. ELISA validation confirmed significantly higher levels of AF EN-RAGE, IL-8, lipocalin-2, MMP-9, S100A8/A9, thrombospondin-2, and TNFR2 in patients with CI than in those with SCX. Multivariable analysis showed that increased AF levels of EN-RAGE, S100A8/A9, and uPA were independently associated with SPTB at < 32 weeks in patients with CI; whereas in patients with SCX, high AF levels of APRIL, EN-RAGE, LBP, and TNFR2 were independently associated with SPTB at < 32 weeks.

Conclusions

Multiple AF proteins show altered expression in patients with CI compared with SCX controls. Moreover, several novel mediators involved in inflammation were identified as potential biomarkers for predicting SPTB after the diagnosis of CI and SCX. These results provide new insights into target-specific molecules for targeted therapies to prevent SPTB in patients with CI/SCX.

Pregnancy Outcome in Women With APECED (APS-1): A Multicenter Study on 43 Females With 83 Pregnancies

CONTEXT

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED; also known as autoimmune polyendocrine syndrome type 1) has a severe, unpredictable course. Autoimmunity and disease components may affect fertility and predispose to maternal and fetal complications, but pregnancy outcomes remain unknown.

OBJECTIVE

To assess fetal and maternal outcomes and course of clinical APECED manifestations during pregnancy in women with APECED.

DESIGN AND SETTING

A multicenter registry-based study including 5 national patient cohorts.

PATIENTS

321 females with APECED.

MAIN OUTCOME MEASURE

Number of pregnancies, miscarriages, and deliveries.

RESULTS

Forty-three patients had altogether 83 pregnancies at median age of 27 years (range, 17-39). Sixty (72%) pregnancies led to a delivery, including 2 stillbirths (2.4%) and 5 (6.0%) preterm livebirths. Miscarriages, induced abortions, and ectopic pregnancies were observed in 14 (17%), 8 (10%), and 1 (1.2%) pregnancies, respectively. Ovum donation resulted in 5 (6.0%) pregnancies. High maternal age, premature ovarian insufficiency, primary adrenal insufficiency, or hypoparathyroidism did not associate with miscarriages. Women with livebirth had, on average, 4 APECED manifestations (range 0-10); 78% had hypoparathyroidism, and 36% had primary adrenal insufficiency. APECED manifestations remained mostly stable during pregnancy, but in 1 case, development of primary adrenal insufficiency led to adrenal crisis and stillbirth. Birth weights were normal in >80% and apart from 1 neonatal death of a preterm baby, no serious perinatal complications occurred.

CONCLUSIONS

Outcome of pregnancy in women with APECED was generally favorable. However, APECED warrants careful maternal multidisciplinary follow-up from preconceptual care until puerperium.

Inflammatory cytokines, placental pathology, and neurological outcomes in infants born to preterm preeclamptic mothers

Preeclampsia is both a vascular and inflammatory disorder. Since the placenta is a conduit for fetal development, preeclampsia should be a presumed cause of adverse infant outcomes. Yet, the relationship of placental pathology, inflammation and neurological outcomes after preeclampsia are understudied. We prospectively examined a cohort of maternal-infant dyads with preeclampsia for maternal inflammatory cytokines at time of preeclampsia diagnosis and delivery, and fetal cord blood cytokines (IL-1β, IL-6, IL-8, and TNF-α). Placentas were analyzed for inflammatory and vascular pathologies. Neurodevelopmental assessment of infants utilizing the Pediatric Stroke Outcome Measure (PSOM) was conducted at 6-month corrected gestational age. Eighty-one maternal-newborn dyads were examined. Worse neurological outcomes were not associated with elevated maternal / fetal cytokines. Early preterm birth (gestational age ≤ 32 weeks) was associated with worse neurological outcomes at 6-months regardless of maternal/ fetal cytokine levels, placental pathology, or cranial ultrasound findings (OR 1.70, [1.16-2.48], p = 0.006). When correcting for gestational age, elevated IL-6 approached significance as a predictor for worse developmental outcome (OR 1.025 [0.985-1.066], p = 0.221). Pathological evidence of maternal malperfusion and worse outcomes were noted in early preterm, although our sample size was small. Our study did not demonstrate an obvious association of inflammation and placental pathology in preeclampsia and adverse neurodevelopmental outcome at 6-month corrected age but does suggest maternal malperfusion at earlier gestational age may be a risk factor for worse outcome.

Direct on-swab metabolic profiling of vaginal microbiome host interactions during pregnancy and preterm birth

The pregnancy vaginal microbiome contributes to risk of preterm birth, the primary cause of death in children under 5 years of age. Here we describe direct on-swab metabolic profiling by Desorption Electrospray Ionization Mass Spectrometry (DESI-MS) for sample preparation-free characterisation of the cervicovaginal metabolome in two independent pregnancy cohorts (VMET, n = 160; 455 swabs; VMET II, n = 205; 573 swabs). By integrating metataxonomics and immune profiling data from matched samples, we show that specific metabolome signatures can be used to robustly predict simultaneously both the composition of the vaginal microbiome and host inflammatory status. In these patients, vaginal microbiota instability and innate immune activation, as predicted using DESI-MS, associated with preterm birth, including in women receiving cervical cerclage for preterm birth prevention. These findings highlight direct on-swab metabolic profiling by DESI-MS as an innovative approach for preterm birth risk stratification through rapid assessment of vaginal microbiota-host dynamics.

Preterm birth is not associated with asymptomatic/mild SARS-CoV-2 infection per se: Pre-pregnancy state is what matters

Evidence for the real impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on preterm birth is unclear, as available series report composite pregnancy outcomes and/or do not stratify patients according to disease severity. The purpose of the research was to determine the real impact of asymptomatic/mild SARS-CoV-2 infection on preterm birth not due to maternal respiratory failure. This case-control study involved women admitted to Sant Anna Hospital, Turin, for delivery between 20 September 2020 and 9 January 2021. The cumulative incidence of Coronavirus disease-19 was compared between preterm birth (case group, n = 102) and full-term delivery (control group, n = 127). Only women with spontaneous or medically-indicated preterm birth because of placental vascular malperfusion (pregnancy-related hypertension and its complications) were included. Current or past SARS-CoV-2 infection was determined by nasopharyngeal swab testing and detection of IgM/IgG antibodies in blood samples. A significant difference in the cumulative incidence of Coronavirus disease-19 between the case (21/102, 20.5%) and the control group (32/127, 25.1%) (P= 0.50) was not observed, although the case group was burdened by a higher prevalence of three known risk factors (body mass index > 24.9, asthma, chronic hypertension) for severe Coronavirus disease-19. Logistic regression analysis showed that asymptomatic/mild SARS-CoV-2 infection was not an independent predictor of spontaneous and medically-indicated preterm birth due to pregnancy-related hypertension and its complications (0.77; 95% confidence interval, 0.41-1.43). Pregnant patients without comorbidities need to be reassured that asymptomatic/mild SARS-CoV-2 infection does not increase the risk of preterm delivery. Preterm birth and severe Coronavirus disease-19 share common risk factors (i.e., body mass index > 24.9, asthma, chronic hypertension), which may explain the high rate of indicated preterm birth due to maternal conditions reported in the literature.

Type 2 and type 3 innate lymphoid cells at the maternal-fetal interface: implications in preterm birth

BACKGROUND

Preterm birth (PTB) is one of the major causes of neonatal morbidity and mortality worldwide. It is commonly accepted that the act of giving birth is the final step in a proinflammatory signaling cascade, orchestrated by an intrauterine milieu coupled to hormonal cues. Consequently, the inflammatory process plays a pivotal role during the pathogenesis of human labor, both in term and preterm deliveries. The ability of innate lymphoid cells (ILCs) to act as pro-inflammatory mediators arose the interest to study their role in normal and pathological pregnancies. The aim of this work was to analyze the relative frequencies of ILCs subsets in pregnancy and the levels of IL-4, IL-17, IL-22, and IFN-γ as inflammatory mediators. Accordingly, we hypothesized that changes in the proportions of ILCs subpopulations could be related to preterm birth.

METHODS

We analyzed 15 full-term delivery samples and six preterm delivery samples. In the full-term group (FTB) peripheral blood was taken during routine blood analysis, on 3 occasions: 1st, 2nd and 3rd trimester. After delivery, peripheral blood, cord blood and placenta were collected. In PTB group, peripheral blood samples were obtained on two occasions: before and 24 h after treatment with progesterone. We used flow cytometry to analyze ILCs in maternal peripheral blood, placenta, and cord blood samples. Maternal peripheral blood and cord blood samples were analyzed by enzyme-linked immunosorbent assay for IL-4, IL-17, IL-22, and IFN-γ plasma levels at the time of labor.

RESULTS

We observed significantly increased relative frequencies of ILC2 and ILC3 in the decidua, as well as an increase of ILC2 in cord blood samples in PTB group, compared to FTB samples. We also found a decrease in IFN-γ in peripheral blood samples of the PTB group, suggesting a functional withdrawal. Additionally, IL-4, IL-17, IL-22 levels were similar in PTB and FTB groups, denoting a relevant role in mediating labor.

CONCLUSION

Our results suggest that ILC2 and ILC3 play a role in PTB by mediating an inflammatory response. Further work is necessary to evaluate the importance of ILCs in the regulation of labor.

Regulatory T Cells Play a Role in a Subset of Idiopathic Preterm Labor/Birth and Adverse Neonatal Outcomes

Regulatory T cells (Tregs) have been exhaustively investigated during early pregnancy; however, their role later in gestation is poorly understood. Herein, we report that functional Tregs are reduced at the maternal-fetal interface in a subset of women with idiopathic preterm labor/birth, which is accompanied by a concomitant increase in Tc17 cells. In mice, depletion of functional Tregs during late gestation induces preterm birth and adverse neonatal outcomes, which are rescued by the adoptive transfer of such cells. Treg depletion does not alter obstetrical parameters in the mother, yet it increases susceptibility to endotoxin-induced preterm birth. The mechanisms whereby depletion of Tregs induces adverse perinatal outcomes involve tissue-specific immune responses and mild systemic maternal inflammation, together with dysregulation of developmental and cellular processes in the placenta, in the absence of intra-amniotic inflammation. These findings provide mechanistic evidence supporting a role for Tregs in the pathophysiology of idiopathic preterm labor/birth and adverse neonatal outcomes.

Cytokine profiling: variation in immune modulation with preterm birth vs. uncomplicated term birth identifies pivotal signals in pathogenesis of preterm birth

OBJECTIVES

To assess deviations in longitudinally measured cytokines with preterm birth (PTB).

METHODS

Prospective longitudinal study targeting 80 subjects. Phlebotomy specimens for broad panel of cytokine analysis were obtained at three time (T) intervals: first trimester (T1: 8-14 weeks' gestation), second trimester (T2: 18-22 weeks' gestation), and third trimester (T3: 28-32 weeks' gestation). Important demographics and outcomes were tracked. Data were stratified and the target groups were analyzed as follows: "Uncomplicated" (delivered ≥37 weeks) or "Preterm Birth" (<37 weeks). Generalized Linear Modeling determined rate of change T1-T3 by outcome.

RESULTS

Complete data replete with phlebotomy at all three visits were obtained on 80 women. Birth outcomes were as follows: 11 Uncomplicated Term Birth (UTB), 28 PTB, 4 low birth weight (LBW), 16 OB complications (OBC), 11 current infections (IFN), and 10 mixed complications (MC=2 or more of the above). 28 PTB were compared to 11 uncomplicated term deliveries. In both groups, T helper type 1 (TH1) cytokine (IL-1β), pleiotrophic pro-inflammatory cytokine (IL-6), and counter-regulatory cytokine (IL-10) responses decreased over gestation, but rates of change in IL-1β, IL-6, and IL-10 were significantly different. Stratification of women by smoking status additionally demonstrated significant variance in immune status over the course of pregnancy.

CONCLUSIONS

Women delivering PTB demonstrated significant differences in cytokine trajectory over pregnancy; these data further validate key role played by immune regulation in directing pregnancy outcome. Likewise, smoking impacts longitudinal trajectory of cytokines over pregnancy.

A Novel Nomogram for Predicting the Risk of Premature Delivery Based on the Thyroid Function in Pregnant Women

BACKGROUND

Maternal thyroid dysfunction and autoantibodies were associated with preterm delivery. However, recommendations for cutoff values of thyroperoxidase antibody (TPOAb) positivity and thyroid-stimulating homone (TSH) associated with premature delivery are lacking.

OBJECTIVE

To identify the pregnancy-specific cutoff values for TPOAb positivity and TSH associated with preterm delivery. To develop a nomogram for the risk prediction of premature delivery based on maternal thyroid function in singleton pregnant women without pre-pregnancy complications.

METHODS

This study included data from the International Peace Maternity and Child Care Health Hospital (IPMCH) in Shanghai, China, between January 2013 and December 2016. Added data between September 2019 and November 2019 as the test cohort. Youden's index calculated the pregnancy-specific cutoff values for TPOAb positivity and TSH concentration. Univariate and multivariable logistic regression analysis were used to screen the risk factors of premature delivery. The nomogram was developed according to the regression coefficient of relevant variables. Discrimination and calibration of the model were assessed using the C-index, Hosmer-Lemeshow test, calibration curve and decision curve analysis.

RESULTS

45,467 pregnant women were divided into the training and validation cohorts according to the ratio of 7: 3. The testing cohort included 727 participants. The pregnancy-specific cutoff values associated with the risk of premature delivery during the first trimester were 5.14 IU/mL for TPOAb positivity and 1.33 mU/L for TSH concentration. Multivariable logistic regression analysis showed that maternal age, history of premature delivery, elevated TSH concentration and TPOAb positivity in the early pregnancy, preeclampsia and gestational diabetes mellitus were risk factors of premature delivery. The C-index was 0.62 of the nomogram. Hosmer-Lemeshow test showed that the Chi-square value was 2.64 (P = 0.955 > 0.05). Decision curve analysis showed a positive net benefit. The calibration curves of three cohorts were shown to be in good agreement.

CONCLUSIONS

We identified the pregnancy-specific cutoff values for TPOAb positivity and TSH concentration associated with preterm delivery in singleton pregnant women without pre-pregnancy complications. We developed a nomogram to predict the occurrence of premature delivery based on thyroid function and other risk factors as a clinical decision-making tool.

Immunology of the Placenta

In this article, the authors provide a general overview of the major immune cells present at the maternal-fetal interface, describe the key mechanisms used by the placenta to promote maternal immune regulation, tolerance, and adaptation, and discuss how dysregulation of these pathways could lead to obstetric complications such as pregnancy loss and preeclampsia. Finally, they conclude with a description of the innate immune properties of the human placenta that not only serve to protect the pregnancy from infection but also contribute to pregnancy complications such as preterm birth.

IL-6: An endogenous activator of MMP-9 in preterm birth

Preterm birth or PTB (<37 weeks) is a heterogeneous phenotype with numerous biological pathways. The lack of explanation due to complex pathways, inconsistent observations indicates the need for employing the role of genetic determinants to anticipate the danger of PTB. In this present study, we investigated the possible gene-gene interaction of five SNPs with PTB and its association with total MMP-9 levels. A total of 510 recruitments (250 terms and preterm each) were made and were genotyped by Restriction Fragment length polymorphism (RFLP). Generalized Multifactor Dimensionality Reduction (GMDR) method was carried out for determining gene-gene interaction. ANOVA and t-test were used to identify the association of IL-6 polymorphism with PTB alone and correspondingly with PTB and low birth weight infants (i.e. < 2500 kg). The combination of IL-6 and MMP-9 and MMP-1, MMP-8 and MMP-9 polymorphism was selected through GMDR analysis concerning mothers with preterm and term birth (accuracy 0.5921 and 0.8030 with Cross-Validation Consistency (CVC) 10/10 respectively). Increased expression of MMP-9 was reported in cases in those mothers carrying IL-6 G allele, which was profoundly associated with PTB independently. IL-6 polymorphisms showed synergistic effects in terms of increased total MMP-9 levels in the present study.

Synthetic PreImplantation Factor (sPIF) reduces inflammation and prevents preterm birth

Preterm birth (PTB) is the leading cause of neonatal morbidity and mortality and spontaneous PTB is a major contributor. The preceding inflammation/infection contributes not only to spontaneous PTB but is associated with neonatal morbidities including impaired brain development. Therefore, control of exaggerated immune response during pregnancy is an attractive strategy. A potential candidate is synthetic PreImplantation Factor (sPIF) as sPIF prevents inflammatory induced fetal loss and has neuroprotective properties. Here, we tested maternal sPIF prophylaxis in pregnant mice subjected to a lipopolysaccharides (LPS) insult, which results in PTB. Additionally, we evaluated sPIF effects in placental and microglial cell lines. Maternal sPIF application reduced the LPS induced PTB rate significantly. Consequently, sPIF reduced microglial activation (Iba-1 positive cells) and preserved neuronal migration (Cux-2 positive cells) in fetal brains. In fetal brain lysates sPIF decreased IL-6 and INFγ concentrations. In-vitro, sPIF reduced Iba1 and TNFα expression in microglial cells and reduced the expression of pro-apoptotic (Bad and Bax) and inflammatory (IL-6 and NLRP4) genes in placental cell lines. Together, maternal sPIF prophylaxis prevents PTB in part by controlling exaggerated immune response. Given the sPIF`FDA Fast Track approval in non-pregnant subjects, we envision sPIF therapy in pregnancy.

The EXTrauterine Environment for Neonatal Development Supports Normal Intestinal Maturation and Development

BACKGROUND AND AIMS

The Extra-Uterine Environment for Neonatal Development (EXTEND) aims to avoid the complications of prematurity, such as NEC. Our goal was to determine if bowel development occurs normally in EXTEND-supported lambs, with specific emphasis on markers of immaturity associated with NEC.

METHODS

We compared terminal ileum from 17 pre-term lambs supported on EXTEND for 2- 4 weeks to bowel from age-matched fetal lambs that developed in utero. We evaluated morphology, markers of epithelial integrity and maturation, enteric nervous system structure, and bowel motility.

RESULTS

EXTEND-supported lamb ileum had normal villus height, crypt depth, density of mucin-containing goblet cells, and enteric neuron density. Expression patterns for I-FABP, activated caspase-3 and EGFR were normal in bowel epithelium. Transmural resistance assessed in Ussing chambers was normal. Bowel motility was also normal as assessed by ex vivo organ bath and video imaging. However, Peyer's patch organization did not occur normally in EXTEND ileum, resulting in fewer circulating B cells in experimental animals.

CONCLUSION

EXTEND supports normal ileal epithelial and enteric nervous system maturation in pre-term lambs. The classic morphologic changes and cellular expression profiles associated with NEC are not seen. However, immune development within the EXTEND supported lamb bowel does not progress normally.

IRAK1 Is a Critical Mediator of Inflammation-Induced Preterm Birth

Preterm birth (PTB) is a major cause of neonatal mortality and morbidity, often triggered by chorioamnionitis or intrauterine inflammation (IUI) with or without infection. Recently, there has been a strong association of IL-1 with PTB. We hypothesized that IL-1R-associated kinase 1 (IRAK1), a key signaling mediator in the TLR/IL-1 pathway, plays a critical role in PTB. In human fetal membranes (FM) collected immediately after birth from women delivering preterm, p-IRAK1 was significantly increased in all the layers of FM with chorioamnionitis, compared with no-chorioamnionitis subjects. In a preterm rhesus macaque model of IUI given intra-amniotic LPS, induction of p-IRAK1 and downstream proinflammatory signaling mediators were seen in the FM. In a C57BL/6J wild-type PTB mouse model of IUI given intrauterine LPS, an IRAK1 inhibitor significantly decreased PTB and increased live birth in a dose-dependent manner. Furthermore, IRAK1 knockout mice were protected from LPS-induced PTB, which was seen in wild-type controls. Activation of IRAK1 was maintained by K63-mediated ubiquitination in preterm FM of humans with chorioamnionitis and rhesus and mouse IUI models. Mechanistically, IRAK1 induced PTB in the mouse model of IUI by upregulating expression of COX-2. Thus, our data from human, rhesus, and mouse demonstrates a critical role IRAK1 in IUI and inflammation-associated PTB and suggest it as potential therapeutic target in IUI-induced PTB.

Influenza-Induced Interferon Lambda Response Is Associated With Longer Time to Delivery Among Pregnant Kenyan Women

Specific causes of preterm birth remain unclear. Several recent studies have suggested that immune changes during pregnancy are associated with the timing of delivery, yet few studies have been performed in low-income country settings where the rates of preterm birth are the highest. We conducted a retrospective nested case-control evaluation within a longitudinal study among HIV-uninfected pregnant Kenyan women. To characterize immune function in these women, we evaluated unstimulated and stimulated peripheral blood mononuclear cells in vitro with the A/California/2009 strain of influenza to understand the influenza-induced immune response. We then evaluated transcript expression profiles using the Affymetrix Human GeneChip Transcriptome Array 2.0. Transcriptional profiles of sufficient quality for analysis were obtained from 54 women; 19 of these women delivered <34 weeks and were defined as preterm cases and 35 controls delivered >37 weeks. The median time to birth from sample collection was 13 weeks. No transcripts were significantly associated with preterm birth in a case-control study of matched term and preterm birth (n = 42 women). In the influenza-stimulated samples, expression of IFNL1 was associated with longer time to delivery-the amount of time between sample collection and delivery (n = 54 women). A qPCR analysis confirmed that influenza-induced IFNL expression was associated with longer time to delivery. These data indicate that during pregnancy, ex vivo influenza stimulation results in altered transcriptional response and is associated with time to delivery in cohort of women residing in an area with high preterm birth prevalence.

Perinatal inflammation influences but does not arrest rapid immune development in preterm babies

Infection and infection-related complications are important causes of death and morbidity following preterm birth. Despite this risk, there is limited understanding of the development of the immune system in those born prematurely, and of how this development is influenced by perinatal factors. Here we prospectively and longitudinally follow a cohort of babies born before 32 weeks of gestation. We demonstrate that preterm babies, including those born extremely prematurely (<28 weeks), are capable of rapidly acquiring some adult levels of immune functionality, in which immune maturation occurs independently of the developing heterogeneous microbiome. By contrast, we observe a reduced percentage of CXCL8-producing T cells, but comparable levels of TNF-producing T cells, from babies exposed to in utero or postnatal infection, which precedes an unstable post-natal clinical course. These data show that rapid immune development is possible in preterm babies, but distinct identifiable differences in functionality may predict subsequent infection mediated outcomes.

Membranous Nephropathy in Pregnancy

BACKGROUND

Primary membranous nephropathy (pMN) is less common in women of child-bearing age. The kidney risk factors to adverse maternal-fetal outcomes and the effects of pregnancy on pMN process need to be investigated.

METHODS

We retrospectively screened all the patients with biopsy-proven pMN from 2008 to 2018. Any cases of pregnancy that occurred at the time of pMN diagnosis or during follow-up were included in the study. Clinical and pathological data were collected from all patients at the time of kidney biopsy and their gestational results were recorded.

RESULTS

Of the 27 pregnancies with gestational time of 35.9 ± 4.5 weeks, 10 adverse maternal-fetal events occurred, including fetal loss (11%), preterm delivery (26%), and severe preeclampsia (15%). The kidney parameters were relatively stable with all preserved kidney function. Time-averaged urinary protein (p < 0.001) and serum albumin (p < 0.001), maximum urinary protein (p = 0.001) and minimum serum albumin (p = 0.01) before week 20, anti-phospholipase A2 receptor (PLA2R) positivity (p = 0.03), and no remission during pregnancy (p = 0.004) were risk factors to adverse maternal-fetal outcomes. Time-averaged urinary protein and serum albumin correlated with the birth weight percentile of neonates.

CONCLUSIONS

Pregnancy in pMN patients showed risks to adverse maternal-fetal events. Heavy proteinuria, especially before week 20 of gestation, severe hypoalbuminemia, positive anti-PLA2R, and no remission were risk factors to worse outcomes.

The Identification of Immune-Related Plasma Proteins Associated with Spontaneous Preterm Delivery and Intra-Amniotic Infection in Women with Premature Cervical Dilation or an Asymptomatic Short Cervix

BACKGROUND

We aimed to investigate whether various immune-related plasma proteins, alone or in combination with conventional clinical risk factors, can predict spontaneous preterm delivery (SPTD) and intra-amniotic infection in women with premature cervical dilation or a short cervix (≤ 25 mm).

METHODS

This retrospective study included 80 asymptomatic women with premature cervical dilation (n = 50) or a short cervix (n = 30), who underwent amniocentesis at 17-29 weeks. Amniotic fluid (AF) was cultured, and maternal plasma was assayed for interleukin (IL)-6, matrix metalloproteinase (MMP)-9, tissue inhibitor of metalloproteinases (TIMP)-1, and complements C3a and C5a, using enzyme-linked immunosorbent assay (ELISA) kits. The primary outcome measures were SPTD at < 32 weeks and positive AF cultures.

RESULTS

The plasma levels of IL-6, C3a, and C5a, but not of MMP-9 and TIMP-1, were significantly higher in women with SPTD at < 32 weeks than in those who delivered at ≥ 32 weeks. The women who delivered at < 32 weeks had more advanced cervical dilatation, and higher rates of antibiotic and tocolytic administration and were less likely to be given vaginal progesterone than those who delivered at ≥ 32 weeks. Using a stepwise regression analysis, a combined prediction model was developed, which included the plasma IL-6 and C3a levels, and cervical dilatation (area under the curve [AUC], 0.901). The AUC for this model was significantly greater than that for any single variable included in the predictive model. In the univariate analysis, plasma IL-6 level was the only significant predictor of intra-amniotic infection.

CONCLUSION

In women with premature cervical dilation or a short cervix, maternal plasma IL-6, C3a, and C5a levels could be useful non-invasive predictors of SPTD at < 32 weeks. A combination of these biomarkers and conventional clinical factors may clearly improve the predictability for SPTD, as compared with the biomarkers alone. An increased plasma level of IL-6 predicted intra-amniotic infection.

Cervical Gene Delivery of the Antimicrobial Peptide, Human β-Defensin (HBD)-3, in a Mouse Model of Ascending Infection-Related Preterm Birth

Approximately 40% of preterm births are preceded by microbial invasion of the intrauterine space; ascent from the vagina being the most common pathway. Within the cervical canal, antimicrobial peptides and proteins (AMPs) are important components of the cervical barrier which help to prevent ascending vaginal infection. We investigated whether expression of the AMP, human β-defensin-3 (HBD3), in the cervical mucosa of pregnant mice could prevent bacterial ascent from the vagina into the uterine cavity. An adeno-associated virus vector containing both the HBD3 gene and GFP transgene (AAV8 HBD3.GFP) or control AAV8 GFP, was administered intravaginally into E13.5 pregnant mice. Ascending infection was induced at E16.5 using bioluminescent Escherichia coli (E. coli K1 A192PP-lux2). Bioluminescence imaging showed bacterial ascent into the uterine cavity, inflammatory events that led to premature delivery and a reduction in pups born alive, compared with uninfected controls. Interestingly, a significant reduction in uterine bioluminescence in the AAV8 HBD3.GFP-treated mice was observed 24 h post-E. coli infection, compared to AAV8 GFP treated mice, signifying reduced bacterial ascent in AAV8 HBD3.GFP-treated mice. Furthermore, there was a significant increase in the number of living pups in AAV HBD3.GFP-treated mice. We propose that HBD3 may be a potential candidate for augmenting cervical innate immunity to prevent ascending infection-related preterm birth and its associated neonatal consequences.

Transcriptome analysis of early pregnancy vitamin D status and spontaneous preterm birth

Background

We conducted a literature review on the studies that investigated the relationship of preterm birth, including spontaneous preterm birth (sPTB), with vitamin D status. Overall, these studies demonstrated that the incidence of sPTB was associated with maternal vitamin D insufficiency in early pregnancy. However, the potential mechanisms and biological pathways are unknown.

Objectives

To investigate early pregnancy gene expression signatures associated with both vitamin D insufficiency and sPTB. We further constructed a network of these gene signatures and identified the common biological pathways involved.

Study design

We conducted peripheral blood transcriptome profiling at 10–18 weeks of gestation in a nested case-control cohort of 24 pregnant women who participated in the Vitamin D Antenatal Asthma Reduction Trial (VDAART). In this cohort, 8 women had spontaneous preterm delivery (21–32 weeks of gestation) and 17 women had vitamin D insufficiency (25-hydroxyvitamin D < 30 ng/mL). We separately identified vitamin D-associated and sPTB gene signatures at 10 to 18 weeks and replicated the overlapping signatures in the mid-pregnancy peripheral blood of an independent cohort with sPTB cases.

Result

At 10–18 weeks of gestation, 146 differentially expressed genes (25 upregulated) were associated with both vitamin D insufficiency and sPTB in the discovery cohort (FDR < 0.05). Of these genes, 43 (25 upregulated) were replicated in the independent cohort of sPTB cases and controls with normal pregnancies (P < 0.05). Functional enrichment and network analyses of the replicated gene signatures suggested several highly connected nodes related to inflammatory and immune responses.

Conclusions

Our gene expression study and network analyses suggest that the dysregulation of immune response pathways due to early pregnancy vitamin D insufficiency may contribute to the pathobiology of sPTB.

Inhibition of Inflammatory Changes in Human Myometrial Cells by Cell Penetrating Peptide and Small Molecule Inhibitors of NFκB

Complications arising from Preterm Birth are the leading causes of neonatal death globally. Current therapeutic strategies to prevent Preterm Birth are yet to demonstrate success in terms of reducing this neonatal disease burden. Upregulation of intracellular inflammatory pathways in uterine cells, including those involving nuclear factor kappa-B (NFκB), have been causally linked to both human term and preterm labor, but the barrier presented by the cell membrane presents an obstacle to interventions aimed at dampening these inflammatory responses. Cell penetrating peptides (CPPs) are novel vectors that can traverse cell membranes without the need for recognition by cell surface receptors and offer the ability to deliver therapeutic cargo internal to cell membranes. Using a human uterine cell culture inflammatory model, this study aimed to test the effectiveness of CPP-cargo delivery to inhibit inflammatory responses, comparing this effect with a small molecule inhibitor (Sc514) that has a similar intracellular target of action within the NFκB pathway (the IKK complex). The CPP Penetratin, conjugated to rhodamine, was able to enter uterine cells within a 60 min timeframe as assessed by live confocal microscopy, this phenomena was not observed with the use of a rhodamine-conjugated inert control peptide (GC(GS)4). Penetratin CPP conjugated to an IKK-inhibitory peptide (Pen-NBD) demonstrated ability to inhibit both the IL1β-induced expression of the inflammatory protein COX2 and dampen the expression of a bespoke array of inflammatory genes. Truncation of the CPP vector rendered the CPP-cargo conjugate much less effective, demonstrating the importance of careful vector selection. The small molecule inhibitor Sc514 also demonstrated ability to inhibit COX2 protein responses and a broad down-regulatory effect on uterine cell inflammatory gene expression. These results support the further exploration of either CPP-based or small molecular treatment strategies to dampen gestational cell inflammatory responses in the context of preterm birth. The work underlines both the importance of careful selection of CPP vector-cargo combinations and basic testing over a broad time and concentration range to ensure effective responses. Further work should demonstrate the effectiveness of CPP-linked cargos to dampen alternative pathways of inflammation linked to Preterm Birth such as MAP Kinase or AP1.

Inflammation induced preterm labor and birth

Preterm birth which occurs before 37 weeks gestation is one of the most common obstetrical complication in humans. After many studies, it appears that "not one answer fits all" regarding the risk factors, causes and the treatments for this syndrome. However, it is becoming more evident that one of the major risk factors is inflammation and/or infection in the fetoplacental unit. In animal models (usually consisting of mice injected with lipopolysaccharide at 14 days of gestation), IL-22 and IL-6 have been identified as factors related to preterm birth. There are some clinical tests available to determine the risk for preterm labor and delivery, which can be identified before, during early, or at mid-gestation. However, treatment of preterm birth with antibiotics so far has not been "curable" and studies using anti-inflammatory treatments are not readily available. More studies regarding causes and treatments for preterm labor and delivery in humans are necessary to prevent neonatal deaths and/or developmental abnormalities associated with this common syndrome.

Autoimmune thyroid disease during pregnancy

Understanding of changes in thyroid function and the consequences of thyroid disease during pregnancy has rapidly grown in the past two decades, and revised American Thyroid Association guidelines on this topic were published in 2017. This Review explores the association between thyroid autoimmunity and complications during and after pregnancy. Thyroid autoimmunity refers to the presence of antibodies to thyroperoxidase or thyroglobulin, or thyroid-stimulating hormone receptor antibodies (TRAbs), or a combination of these, and is present in up to 18% of pregnant women. Thyroid antibodies in pregnant women with normal functioning thyroids (ie, euthyroid) have been associated with several complications, including miscarriage and premature delivery. Treatments to improve pregnancy outcomes are being studied. Whether thyroid antibodies are associated with infertility and assisted reproductive technology outcomes is unclear; although, treatment with low doses of levothyroxine, which is usually used to treat hypothyroidism, can be considered in such situations. Additionally, thyroid antibodies have been associated with other neonatal and maternal complications. All these associations require confirmation in larger prospective studies, and their pathogenic mechanisms need to be better understood. Post-partum thyroiditis is substantially more frequent in women who have thyroid antibodies during pregnancy than in those who do not have thyroid antibodies; however, whether treatment can prevent post-partum thyroiditis in women who are or have been antibody positive is unknown. Finally, TRAbs cross the placenta from the mother to the fetus and can cause fetal or neonatal hyperthyroidism. Therefore, women who are positive for TRAbs during pregnancy should be monitored.

Inflamatory response in pregnant women with high risk of preterm delivery and its relationship with periodontal disease: a pilot study

Periodontal disease and its inflammatory response have been related to adverse outcomes in pregnancy such as preterm birth, preeclampsia and low birth weight. This study analyzed systemic inflammatory response in patients with high risk of preterm delivery and its relationship to periodontal disease. A pilot study was conducted for a case and control study, on 23 patients at risk of preterm delivery and 23 patients without risk of preterm delivery as controls. Exclusion criteria were patients who had received periodontal treatment, antibiotic or antimicrobial agents within the past three months, or with infections or baseline diseases such as diabetes or hypercholesterolemia. All patients underwent periodontal assessment, laboratory tests (complete blood count, lipid profile, baseline glycemia) and quantification of cytokines (IL-2, IL-4, IL-6, IL-10, TNF-α and TNF-γ). Higher levels of pro-inflammatory cytokines (IL-2, IL-4, IL-6, IL-10, TNF-α and TNF-γ) were found in patients with chronic periodontitis than in patients with gingivitis or periodontal health. These cytokines, in particular IL-2, IL-10 and TNF-α, were higher in patients at high risk of preterm delivery. Patients with high risk of preterm delivery had higher severity of periodontal disease as well as higher levels of the pro-inflammatory markers IL-2, IL-4, IL-6, IL-10, TNF-α and TNF-γ.

Impact of maternal thyroid autoantibodies positivity on the risk of early term birth: Ma'anshan Birth Cohort Study

PURPOSE

We aim to investigate associations of maternal serum anti-thyroperoxidase autoantibody (TPOAb) with duration of gestation. We aim to investigate whether maternal TPOAb positivity is associated with the risk of premature or early term birth.

METHODS

This was a prospective birth cohort study performed in an iodine sufficient area of China. Serum samples were collected from 2931 women at both the first and second trimesters of pregnancy. Thyrotropin (TSH), free thyroxine (FT4), and TPOAb levels were measured. Data on gestational age at birth was obtained from delivery records.

RESULTS

The prevalence of early term birth was 23.8%, while the prevalence of premature birth was 4.2%. The prevalence of TPOAb positivity was 12.1% in the first trimester and was 7.2% in the second trimester. Gestational age at birth was inversely associated with lgTPOAb both in the first trimester (β, -0.283, 95% CI -0.408, -0.158; P < 0.001) and in the second trimester (β, -0.174, 95% CI -0.319, -0.030; P = 0.018), after adjustment for potential confounding factors. There was a positive association of TPOAb positivity with the risk of early term birth both in the first (OR = 1.691, 95% CI 1.302, 2.197) and second trimesters (OR = 1.644, 95% CI 1.193, 2.264), after adjustment for potential confounding factors. TPOAb positivity in the second trimester was associated with a 1.863-fold higher risk of premature birth (OR = 1.863, 95% CI 1.009, 3.441), after adjustment for potential confounding factors.

CONCLUSIONS

Our results show that TPOAb is associated with shorter duration of gestation and with higher risk of premature and early term birth.

Mid-gestational changes in cervicovaginal fluid cytokine levels in asymptomatic pregnant women are predictive markers of inflammation-associated spontaneous preterm birth

OBJECTIVES

Perturbation of the choriodecidual space before the onset of spontaneous preterm birth (sPTB) could lead to a concomitant rise in both cervicovaginal fluid (CVF) cytokine and fetal fibronectin (FFN), and assessing the concentrations of both markers could improve the prediction of sPTB (delivery before 37 completed weeks of gestation). Therefore, we prospectively determined mid-trimester changes in CVF cytokine and FFN concentrations, and their predictive capacity for sPTB in asymptomatic pregnant women.

STUDY DESIGN

CVF collected at 20+0-22+6 weeks (n = 47: Preterm-delivered = 22, Term-delivered = 25) and 26+0-28+6 weeks (n = 50: Preterm-delivered = 17, Term-delivered = 33) from 63 asymptomatic pregnant women at risk of sPTB were examined. Cytokine and FFN concentrations were determined by multiplexed bead-based immunoassay and 10Q Rapid analysis (Hologic, MA, USA) respectively. The 20+0-22+6/26+0-28+6 weeks ratios of cytokines and FFN concentrations were compared between preterm- and term-delivered women using Receiver Operating Characteristics curves to predict sPTB. Also, bacterial 16S rDNA from 64 samples (20+0-22+6 weeks n = 36, 26+0-28+6 weeks n = 28) was amplified by polymerase chain reaction to determine associations between vaginal microflora, cytokine and FFN concentrations.

RESULTS

Changes in RANTES and IL-1β concentrations between 20+0-22+6 and 26+0-28+6 weeks, expressed as a ratios, were predictive of sPTB, RANTES (AUC = 0.82, CI = 0.62-0.94) more so than IL-1β (AUC = 0.71, CI = 0.53-0.85) and FFN (not predictive). Combining these markers (AUC = 0.83, CI = 0.63-0.95) showed similar predictive capacity as RANTES alone. FFN concentrations at 26+0-28+6 weeks correlated with IL-1β (r = 0.4, P = 0.002) and RANTES (r = 0.3, P = 0.03). In addition, there was increased prevalence of vaginal anaerobes including Bacteroides, Fusobacterium and Mobiluncus between gestational time points in women who experienced sPTB compared to the term women (P = 0.0006).

CONCLUSIONS

CVF RANTES and IL-1β in mid-trimester of pregnancy correlate with quantitative FFN. The levels of CVF RANTES and IL-1β decline significantly in women who deliver at term unlike women who deliver preterm. This observation suggests that sPTB may be characterised by sustained choriodecidual inflammation and may have clinical value in serial screening for sPTB if confirmed by larger studies.

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.

Dose Dependency and a Functional Cutoff for TPO-Antibody Positivity During Pregnancy

OBJECTIVE

To investigate a dose dependency of thyroperoxidase antibody (TPOAb) concentrations in relation to thyroid function and premature delivery and define a population-based, pregnancy-specific, functional cutoff for TPOAb positivity.

DESIGN

Individual participant meta-analysis of three prospective birth cohorts: the Amsterdam Born Children and their Development study, and the Holistic Approach to Pregnancy.

SETTING

Population-based studies in the Netherlands (2002 to 2014).

PARTICIPANTS

A total of 11,212 pregnant women (<20 weeks' gestation).

MAIN OUTCOME MEASURES

Thyrotropin (TSH) and FT4 concentrations, premature delivery.

RESULTS

In all cohorts, there was a dose-dependent positive association of TPOAb concentrations with TSH concentrations, as well as a dose-dependent negative association with FT4 concentrations during early pregnancy (all P < 0.0001). There was a dose-dependent association of TPOAb concentrations with the risk of premature delivery, which was also modified by TSH concentrations. Women with TPOAb concentrations from the 92nd percentile upward had a higher TSH and a higher risk of a TSH >2.5 mU/L (range, 19.4% to 51.3%). Stratified analyses showed that women with TPOAb concentrations below manufacturer cutoffs already had a higher risk of premature delivery, especially when TSH concentrations were high or in the high-normal range.

CONCLUSIONS

This study demonstrated a dose-dependent relationship between TPOAbs and thyroid function as well as the risk of premature delivery. Furthermore, our results indicate that the currently used cutoffs for TPOAb positivity may be too high. Furthermore, the use of a population-based cutoff for TPOAbs may identify women with a clinically relevant extent of thyroid autoimmunity and a higher risk of premature delivery but that would not be considered TPOAb positive or eligible for treatment otherwise.

Thyroid Function and Premature Delivery in TPO Antibody-Negative Women: The Added Value of hCG

CONTEXT

Human chorionic gonadotropin (hCG) stimulates thyroid function during pregnancy. We recently showed that thyroid autoimmunity severely attenuated the thyroidal response to hCG stimulation and that this may underlie the higher risk of premature delivery in thyroperoxidase antibody (TPOAb)-positive women. We hypothesized that a lower thyroidal response to hCG stimulation in TPOAb-negative women is also associated with a higher risk of premature delivery and preterm premature rupture of membranes (pPROM).

DESIGN, SETTING, AND PARTICIPANTS

Thyrotropin (TSH), free thyroxine (FT4), and hCG concentrations were available in 5644 TPOAb-negative women from a prospective cohort. We tested for interaction between TSH or FT4 and hCG in linear regression models for duration of pregnancy and logistic regression models for premature delivery/pPROM. Accordingly, analyses were stratified per TSH percentile (TSH ≥ 85th percentile) and hCG per 10,000 IU/L.

RESULTS

Women with high TSH and low hCG concentrations did not have a higher risk of premature delivery or pPROM, with protective effect estimates. In contrast, women with a high TSH concentration despite a high hCG concentration had twofold to 10-fold higher risk of premature delivery (Pdifference = 0.022) and an up to fourfold higher risk of pPROM (Pdifference = 0.079). hCG concentrations were not associated with premature delivery or pPROM.

CONCLUSION

In TPOAb-negative women with high-normal TSH concentrations, only women with high hCG concentrations had a higher risk of premature delivery or pPROM. These results suggest a lower thyroidal response to hCG stimulation is also associated with premature delivery in TPOAb-negative women and that an additional measurement of hCG may improve thyroid-related risk assessments during pregnancy.

Differential lower airway dendritic cell patterns may reveal distinct endotypes of RSV bronchiolitis

RATIONALE

The pathogenesis of respiratory syncytial virus (RSV) bronchiolitis in infants remains poorly understood. Mouse models implicate pulmonary T cells in the development of RSV disease. T cell responses are initiated by dendritic cells (DCs), which accumulate in lungs of RSV-infected mice. In infants with RSV bronchiolitis, previous reports have shown that DCs are mobilised to the nasal mucosa, but data on lower airway DC responses are lacking.

OBJECTIVE

To determine the presence and phenotype of DCs and associated immune cells in bronchoalveolar lavage (BAL) and peripheral blood samples from infants with RSV bronchiolitis.

METHODS

Infants intubated and ventilated due to severe RSV bronchiolitis or for planned surgery (controls with healthy lungs) underwent non-bronchoscopic BAL. Immune cells in BAL and blood samples were characterised by flow cytometry and cytokines measured by Human V-Plex Pro-inflammatory Panel 1 MSD kit.

MEASUREMENTS AND MAIN RESULTS

In RSV cases, BAL conventional DCs (cDCs), NK T cells, NK cells and pro-inflammatory cytokines accumulated, plasmacytoid DCs (pDCs) and T cells were present, and blood cDCs increased activation marker expression. When stratifying RSV cases by risk group, preterm and older (≥4 months) infants had fewer BAL pDCs than term born and younger (<4 months) infants, respectively.

CONCLUSIONS

cDCs accumulate in the lower airways during RSV bronchiolitis, are activated systemically and may, through activation of T cells, NK T cells and NK cells, contribute to RSV-induced inflammation and disease. In addition, the small population of airway pDCs in preterm and older infants may reveal a distinct endotype of RSV bronchiolitis with weak antiviral pDC responses.

Staphylococcus aureus Infection of Human Gestational Membranes Induces Bacterial Biofilm Formation and Host Production of Cytokines

Staphylococcus aureus, a metabolically flexible gram-positive pathogen, causes infections in a variety of tissues. Recent evidence implicates S. aureus as an emerging cause of chorioamnionitis and premature rupture of membranes, which are associated with preterm birth and neonatal disease. We demonstrate here that S. aureus infects and forms biofilms on the choriodecidual surface of explanted human gestational membranes. Concomitantly, S. aureus elicits the production of proinflammatory cytokines, which could ultimately perturb maternal-fetal tolerance during pregnancy. Therefore, targeting the immunological response to S. aureus infection during pregnancy could attenuate disease among infected individuals, especially in the context of antibiotic resistance.

Thyroid Autoimmunity Impairs the Thyroidal Response to Human Chorionic Gonadotropin: Two Population-Based Prospective Cohort Studies

CONTEXT

Thyroperoxidase antibody (TPOAb) positivity is the main risk factor for thyroid dysfunction during pregnancy and is consistently associated with premature delivery. However, the underlying mechanism is currently unknown. We hypothesized that TPOAb positivity may interfere with gestational thyroid stimulation induced by the pregnancy hormone human chorionic gonadotropin (hCG).

DESIGN, SETTING, AND PARTICIPANTS

Thyrotropin (TSH), free thyroxine (FT4), TPOAbs, and/or hCG concentrations were measured in early and late pregnancy of 7587 pregnant women from 2 Dutch population-based prospective cohorts (n = 5924, Generation R study; n = 1663, Holistic Approach to Pregnancy and the First Postpartum Year study).

INTERVENTIONS

None.

MAIN OUTCOME MEASURE(S)

Thyroidal response to hCG stimulation, premature delivery.

RESULTS

In TPOAb-negative women, hCG was positively associated with FT4 and negatively with TSH in both cohorts (P < 0.0001). In contrast, in TPOAb-positive women, hCG was not associated with FT4 or TSH in either cohort (all P > 0.40; P for interaction TPOAb positive vs negative ≤ 0.05). Overall, TPOAb positivity was associated with a 1.7-fold higher risk of premature delivery. TPOAb-positive women with an adequate response of FT4 to hCG (high FT4 concentration with high hCG concentration) did not have a higher risk of premature delivery. In contrast, TPOAb-positive women with an inadequate FT4 response to hCG (low FT4 concentration with high hCG concentration) had a 2.2- to 2.8-fold higher risk of premature delivery.

CONCLUSION

TPOAb-positive women display an impaired thyroidal response to hCG and this may explain the higher risk of premature delivery in these women. This abnormal response in TPOAb-positive women might suggest that these women require a different treatment approach than TPOAb-negative women.

Ethnic Differences in Preterm Birth Risks for Pregnant Women with Thyroid Dysfunction or Autoimmunity: A Meta-analysis

OBJECTIVE

Abnormal maternal thyroid function is associated with preterm birth. However, this association stays dubious in relevant individual studies for ethnic difference reasons and lack of direct supporting data. This study aimed to evaluate the relationship between preterm birth and thyroid dysfunction or autoimmunity based on ethnic differences.

METHODS

Relevant studies were identified through searches of MEDLINE, Excerpta Medica, Wan Fang, China Biological Medicine disc, and China National Knowledge Infrastructure from inception to June 15, 2016. Original articles in which an incidence or prevalence of thyroid dysfunction or autoimmunity before second trimester of pregnancy could be extracted were included.

RESULTS

Thirty-two unique studies were included for the final meta-analysis. Patients involved were divided into two groups: Group 1 (G1) and Group 2 (G2) comprising of Asian and Caucasian populations, respectively. Positive thyroid antibodies were associated with the occurrence of preterm birth in both G1 [odds ratio (OR): 3.62, 95% confidence interval (CI): 2.83-4.65] and G2 (OR: 1.35, 95% CI: 1.17-1.56); hypothyroidism, only in G2 (OR: 1.20, CI: 1.09-1.33); and subclinical hypothyroidism or hypothyroxinemia, in neither group.

CONCLUSION

Thyroid autoimmunity may be a more favorable factor leading to preterm birth among pregnant women of different ethnicities, compared with thyroid dysfunction.

Regulatory Cytokine Expression and Preterm Birth: Case-Control Study Nested in a Cohort

Background

Currently known risk factors explain only a small fraction of preterm birth (PTB). Previous PTB is one of the most important predictors. However, this information is not available in primiparous women. Few studies have looked at associations between regulatory cytokine expression (RCE) and PTB and the results are conflicting.

Objective

To investigate the association of RCE–Interleukin 10 (IL-10) and Transforming Growth Factor β (TGF-β)–with PTB, and to assess whether bacterial vaginosis (BV) is involved in this relationship.

Methods

This was a case-control study nested in a prospective cohort–called BRISA. Women with singleton pregnancies were interviewed from 22 to 25 weeks of gestational age (GA). Women were recruited from health services in São Luís, Brazil. A blood sample was collected and gynecological examination was performed. Serum IL-10 and TGF-β were determined using cytometric bead array. Nugent score >7 and/or the presence of clue cells were used for BV diagnosis. All PTB estimated by ultrasound dating performed before 20 weeks of gestational age were considered cases. Controls were selected by simple random sampling from the rest of the cohort, at a 2:1 ratio. Different models were tested, according to the main independent variable. Odds ratios (OR) and 95% confidence intervals (95%CI) were estimated by regression analyses.

Results

The study included 327 pregnant women, 109 cases and 218 controls. No associations were found between BV and PTB (P = 1.44; 95%CI: 0.51–3.77). Low levels of IL-10 (OR = 2.92 95%CI: 1.38–6.16) or TGF-β (OR = 16.90 95%CI: 6.42–44.51) or both simultaneously (OR = 77.16 95%CI: 7.99–744.88) were associated with increasing odds of PTB, even after adjustment for confounding.

Conclusion

Decreased RCE is a risk factor for PTB. This relationship, however, is not triggered by the presence of BV. Low IL-10/TGF-β levels from 22 to 25 weeks of GA could be used as early predictors of PTB. We suggest monitoring of these RCE, especially among primiparous women, for whom history of previous PTB is not available.

Risk of Preterm or Small-for-Gestational-Age Birth After Influenza Vaccination During Pregnancy: Caveats When Conducting Retrospective Observational Studies

Vaccines are increasingly targeted toward women of reproductive age, and vaccines to prevent influenza and pertussis are recommended during pregnancy. Prelicensure clinical trials typically have not included pregnant women, and when they are included, trials cannot detect rare events. Thus, postmarketing vaccine safety assessments are necessary. However, analysis of observational data requires detailed assessment of potential biases. Using data from 8 Vaccine Safety Datalink sites in the United States, we analyzed the association of monovalent H1N1 influenza vaccine (MIV) during pregnancy with preterm birth (<37 weeks) and small-for-gestational-age birth (birth weight < 10th percentile). The cohort included 46,549 pregnancies during 2009-2010 (40% of participants received the MIV). We found potential biases in the vaccine-birth outcome association that might occur due to variable access to vaccines, the time-dependent nature of exposure to vaccination within pregnancy (immortal time bias), and confounding from baseline differences between vaccinated and unvaccinated women. We found a strong protective effect of vaccination on preterm birth (relative risk = 0.79, 95% confidence interval: 0.74, 0.85) when we ignored potential biases and no effect when accounted for them (relative risk = 0.91; 95% confidence interval: 0.83, 1.0). In contrast, we found no important biases in the association of MIV with small-for-gestational-age birth. Investigators conducting studies to evaluate birth outcomes after maternal vaccination should use statistical approaches to minimize potential biases.

An imbalance between innate and adaptive immune cells at the maternal-fetal interface occurs prior to endotoxin-induced preterm birth

Preterm birth (PTB) is the leading cause of neonatal morbidity and mortality worldwide. A transition from an anti-inflammatory state to a pro-inflammatory state in the mother and at the maternal-fetal interface has been implicated in the pathophysiology of microbial-induced preterm labor. However, it is unclear which immune cells mediate this transition. We hypothesized that an imbalance between innate and adaptive immune cells at the maternal-fetal interface will occur prior to microbial-induced preterm labor. Using an established murine model of endotoxin-induced PTB, our results demonstrate that prior to delivery there is a reduction of CD4+ regulatory T cells (Tregs) in the uterine tissues. This reduction is neither linked to a diminished number of Tregs in the spleen, nor to an impaired production of IL10, CCL17, or CCL22 by the uterine tissues. Endotoxin administration to pregnant mice does not alter effector CD4+ T cells at the maternal-fetal interface. However, it causes an imbalance between Tregs (CD4+ and CD8+), effector CD8+ T cells, and Th17 cells in the spleen. In addition, endotoxin administration to pregnant mice leads to an excessive production of CCL2, CCL3, CCL17, and CCL22 by the uterine tissues as well as abundant neutrophils. This imbalance in the uterine microenvironment is accompanied by scarce APC-like cells such as macrophages and MHC II+ neutrophils. Collectively, these results demonstrate that endotoxin administration to pregnant mice causes an imbalance between innate and adaptive immune cells at the maternal-fetal interface.

Ultrasonographic approach to diagnosis of fetal inflammatory response syndrome: a tool for at-risk fetuses?

Preterm parturition is a syndrome that may result from many underlying mechanisms. Infection and inflammation are the prominent ones. Intrauterine infection and inflammation have an effect akin to sepsis, and that is similar to systemic inflammatory response in adults. Indeed, there is evidence to support the association of a fetal inflammatory response syndrome (FIRS) to systemic infection and inflammation. The utilization of invasive procedures for the prenatal diagnosis of FIRS is associated with a risk for complications resulting from the invasive method. The progress in the imaging quality of obstetrical ultrasound and the development of novel methods for functional anatomical assessment of the fetal organs may help to identify, noninvasively, fetuses at risk for FIRS in patients presenting with preterm labor. We review the studies describing advanced sonographic modalities and the imaging findings in the heart, thymus, kidney, adrenal glands, and spleen of these fetuses.

[SOME CLINICAL AND IMMUNOLOGICAL ASPECTS OF PRETERM BIRTH]

Aim - to make a comparative assessment of the cytokines level in women with preterm labor with chronic infection and without it in order to determine the risk of implementation of intrauterine infection in their preterm infants. There was prospective investigation of 141 pregnant and their 141 premature infants with different gestation terms. There was identify cytokines levels in mother's blood with immune enzyme analysis method due implementation of intrauterine infection in compare with control group. It wasinterconnection ofinfection pathology withgestation terms, it lead to preterm labor. Prematurity which cause by mothers chronic infection, lead to heavier, extended period of bacterial infection in premature infants. It was increasing of cytokines levels IL-1β, IL-6, and TNF-α of mother's blood during implementation of intrauterine infection in premature infants. Multiparous pregnant, adverse outcomes of previous pregnancies in anamnesis, high frequency carrier of bacterial infection were risk factors for preterm labor among explored pregnant women. To study cytokine profile among the explored pregnant women from main group showed a pattern in increasing of level IL-1β, IL- 6 and TNF-α serum during pregnancy , indicating the course of pregnancy and can be used as a nonspecific marker for early diagnosis of preterm birth and implementing infection in premature . The level of IL-2 did not have a diagnostic value.

Efficacy of midtrimester short cervix interventions is conditional on intraamniotic inflammation

BACKGROUND

Midtrimester ultrasound is a valuable method for identifying asymptomatic women at risk for spontaneous preterm delivery (PTD). However, response to various treatments (cerclage, progestogen) has been variable in the clinical setting. It remains unclear how other biomarkers may be used to guide intervention strategies.

OBJECTIVE

We applied an amniotic fluid inflammatory scoring system to determine if the degree of inflammation is associated with intervention efficacy in patients with midtrimester short cervix.

STUDY DESIGN

Women carrying a singleton fetus between 16-24 weeks' gestation with a short cervix (≤25 mm) on transvaginal ultrasound underwent amniocentesis and were assigned to McDonald cerclage, no cerclage, or weekly 17-alpha hydroxyprogesterone caproate (17OHP-C). Our previously described inflammatory risk score (comprised of 14 inflammatory markers) was used to classify patients as high (score ≥8) or low (score <8) risk for inflammation. Gestational age at delivery was compared for each intervention and risk score status. Risk of delivering as a function of the remaining gestation was evaluated using modified Cox proportional hazards models with incorporation of methods to account for both left and right truncation bias.

RESULTS

Ninety patients were included: 24 were in the nonintervention control group, 51 received cerclage, and 15 received 17OHP-C. Inflammation status at time of sampling influenced the efficacy of the treatment (P < .001). Compared to the nonintervention control group, in patients with low inflammation (score < 8), both cerclage (adjusted hazard ratio [HR], 2.86; 95% confidence interval [CI], 1.28-6.37) and 17OHP-C (HR, 3.11; 95% CI, 1.04-9.30) were associated with increased hazard of PTD. In contrast, in patients with high inflammation (score ≥8) both cerclage (HR, 0.22; 95% CI, 0.08-0.65) and 17OHP-C (HR, 0.20; 95% CI, 0.05-0.81) were associated with lower hazard of delivering preterm.

CONCLUSION

Cerclage placement or administration of 17OHP-C therapy for midtrimester short cervix for PTD prevention appears beneficial only in the subset of patients with high inflammation. Knowledge of the amniotic fluid inflammatory status may aid in guiding the appropriate therapy for women presenting with midtrimester short cervix who are at increased risk of PTD.

Implementing Mass Cytometry at the Bedside to Study the Immunological Basis of Human Diseases: Distinctive Immune Features in Patients with a History of Term or Preterm Birth

Single-cell technologies have immense potential to shed light on molecular and biological processes that drive human diseases. Mass cytometry (or Cytometry by Time Of Flight mass spectrometry, CyTOF) has already been employed in clinical studies to comprehensively survey patients' circulating immune system. As interest in the "bedside" application of mass cytometry is growing, the delineation of relevant methodological issues is called for. This report uses a newly generated dataset to discuss important methodological considerations when mass cytometry is implemented in a clinical study. Specifically, the use of whole blood samples versus peripheral blood mononuclear cells (PBMCs), design of mass-tagged antibody panels, technical and analytical implications of sample barcoding, and application of traditional and unsupervised approaches to analyze high-dimensional mass cytometry datasets are discussed. A mass cytometry assay was implemented in a cross-sectional study of 19 women with a history of term or preterm birth to determine whether immune traits in peripheral blood differentiate the two groups in the absence of pregnancy. Twenty-seven phenotypic and 11 intracellular markers were simultaneously analyzed in whole blood samples stimulated with lipopolysaccharide (LPS at 0, 0.1, 1, 10, and 100 ng mL(-1)) to examine dose-dependent signaling responses within the toll-like receptor 4 (TLR4) pathway. Complementary analyses, grounded in traditional or unsupervised gating strategies of immune cell subsets, indicated that the prpS6 and pMAPKAPK2 responses in classical monocytes are accentuated in women with a history of preterm birth (FDR<1%). The results suggest that women predisposed to preterm birth may be prone to mount an exacerbated TLR4 response during the course of pregnancy. This important hypothesis-generating finding points to the power of single-cell mass cytometry to detect biologically important differences in a relatively small patient cohort.

Murine model: maternal administration of stem cells for prevention of prematurity

OBJECTIVE

Using a mouse model of intrauterine inflammation, we have demonstrated that exposure to inflammation induces preterm birth and perinatal brain injury. Mesenchymal stem cells (MSCs) have been shown to exhibit immunomodulatory effects in many inflammatory conditions. We hypothesized that treatment with human adipose tissue-derived MSCs may decrease the rate of preterm birth and perinatal brain injury through changes in antiinflammatory and regulatory milieu.

STUDY DESIGN

A mouse model of intrauterine inflammation was used with the following groups: (1) control; (2) intrauterine inflammation (lipopolysaccharide); and (3) intrauterine lipopolysaccharide+intraperitoneal (MSCs). Preterm birth was investigated. Luminex multiplex enzyme-linked immunosorbent assays were performed for protein levels of cytokines in maternal and fetal compartments. Immunofluorescent staining was used to identify and localize MSCs and to examine microglial morphologic condition and neurotoxicity in perinatal brain. Behavioral testing was performed at postnatal day 5.

RESULTS

Pretreatment with MSCs significantly decreased the rate of preterm birth by 21% compared with the lipopolysaccharide group (P<.01). Pretreatment was associated with increased interleukin-10 in maternal serum, increased interleukin-4 in placenta, decreased interleukin-6 in fetal brain (P<.05), decreased microglial activation (P<.05), and decreased fetal neurotoxicity (P<.05). These findings were associated with improved neurobehavioral testing at postnatal day 5 (P<.05). Injected MSCs were localized to placenta.

CONCLUSION

Maternally administered MSCs appear to modulate maternal and fetal immune response to intrauterine inflammation in the model and decrease preterm birth, perinatal brain injury, and motor deficits in offspring mice.

Fetal and early neonatal interleukin-6 response

In 1998, a systemic fetal cytokine response, defined as a plasma interleukin-6 (IL-6) value above 11 pg/mL, was reported to be a major independent risk factor for the subsequent development of neonatal morbid events even after adjustments for gestational age and other confounders. Since then, the body of literature investigating the use of blood concentrations of IL-6 as a hallmark of the fetal inflammatory response syndrome (FIRS), a diagnostic marker of early-onset neonatal sepsis (EONS) and a risk predictor of white matter injury (WMI), has grown rapidly. In this article, we critically review: IL-6 biological functions; current evidence on the association between IL-6, preterm birth, FIRS and EONS; IL-6 reference intervals and dynamics in the early neonatal period; IL-6 response during the immediate postnatal period and perinatal confounders; accuracy and completeness of IL-6 diagnostic studies for EONS (according to the Standards for Reporting of Diagnostic Accuracy statement); and recent breakthroughs in the association between fetal blood IL-6, EONS, and WMI.

The complement system and adverse pregnancy outcomes

Adverse pregnancy outcomes significantly contribute to morbidity and mortality for mother and child, with lifelong health consequences for both. The innate and adaptive immune system must be regulated to insure survival of the fetal allograft, and the complement system is no exception. An intact complement system optimizes placental development and function and is essential to maintain host defense and fetal survival. Complement regulation is apparent at the placental interface from early pregnancy with some degree of complement activation occurring normally throughout gestation. However, a number of pregnancy complications including early pregnancy loss, fetal growth restriction, hypertensive disorders of pregnancy and preterm birth are associated with excessive or misdirected complement activation, and are more frequent in women with inherited or acquired complement system disorders or complement gene mutations. Clinical studies employing complement biomarkers in plasma and urine implicate dysregulated complement activation in components of each of the adverse pregnancy outcomes. In addition, mechanistic studies in rat and mouse models of adverse pregnancy outcomes address the complement pathways or activation products of importance and allow critical analysis of the pathophysiology. Targeted complement therapeutics are already in use to control adverse pregnancy outcomes in select situations. A clearer understanding of the role of the complement system in both normal pregnancy and complicated or failed pregnancy will allow a rational approach to future therapeutic strategies for manipulating complement with the goal of mitigating adverse pregnancy outcomes, preserving host defense, and improving long term outcomes for both mother and child.

Dynamics of the NK-cell subset redistribution induced by cytomegalovirus infection in preterm infants

Human cytomegalovirus (HCMV) infection promotes an expansion of NK-cells expressing the CD94/NKG2C receptor. We prospectively monitored the effects of HCMV on the NK-cell receptor (NKG2C, NKG2A, KIR, LILRB1) distribution in preterm infants. As compared to non-infected moderately preterm newborns (n=19, gestational age: 32-37 weeks), very preterm infants (n=5, gestational age: <32 weeks) suffering symptomatic postnatal HCMV infection displayed increased numbers of NKG2C+, KIR+ NK-cells, encompassed by a reduction of NKG2A+ NK-cells. A similar profile was observed in HCMV-negative newborns (n=4) with asymptomatic infection, during follow-up at ~4 and 10 months of age. Of note, viremia remained detectable in three symptomatic cases at ~10 months despite the persistent expansion of NKG2C+ NK-cells. Our study provides original insights on the dynamics of the imprint exerted by primary HCMV infection on the NK-cell compartment, revealing that the expansion of NKG2C+ NK-cells may be insufficient to control viral replication in very preterm infants.

Thyroid autoimmunity in pregnancy and its influences on maternal and fetal outcome in Iran (a prospective study)

AIM OF THE STUDY

Thyroid dysfunction and autoimmunity are common problems in women of child-bearing age. It could be associated with pregnancy morbidities in the mother and fetus. Due to lack of sufficient data about the prevalence of thyroid autoimmunity in pregnant women in Iran, and controversies about its complications on pregnancy outcomes, this study was conducted.

MATERIALS AND METHODS

This is a prospective study on 600 singleton pregnant women in 15-28 weeks of pregnancy; they were residents of Fars province. We evaluated the prevalence of preeclampsia, intra-uterine growth retardation (IUGR), preterm delivery and low Apgar score and their association with TSH, thyroid peroxidase (TPO), and thyroglobulin (Tg) antibodies.

RESULTS

Prevalence of anti-TPO and anti-Tg positivity is 12.8% and 8.5% among Iranian pregnant women. Mothers with either positive TPO or Tg antibody have a higher risk of preeclampsia (p = 0.019), preterm delivery (p < 0.001), IUGR (p < 0.001), and low first minute Apgar score (p < 0.001). This association was independent of thyroid dysfunction for preterm delivery (RR = 5, p < 0.001), and low Apgar score neonates (RR = 8.8, p < 0.001), but this association for preeclampsia was due to thyroid dysfunction (RR = 3.7, p = 0.003). About IUGR in either TPO or Tg positive mothers, this association results from the additive effect of thyroid dysfunction and thyroid autoimmunity (RR = 8.3, p < 0.001). Cesarean section delivery was significantly higher in abnormal TSH/positive anti-Tg mothers (p = 0.045).

CONCLUSION

Thyroid autoimmunity independent of thyroid dysfunction could have significant adverse outcomes in the mother and fetus. Further investigation should be done to reveal the significance of screening and treating the thyroid autoimmunity during pregnancy.

Hyaluronan in cervical epithelia protects against infection-mediated preterm birth

Increased synthesis of cervical hyaluronan (HA) from early to late pregnancy has long been proposed to play an essential role in disorganization of the collagen-rich extracellular matrix to allow for maximal compliance and dilation of the cervix during the birth process. Here, we show that HA is not essential for increased cervical distensibility during late pregnancy. Rather, cervicovaginal HA plays an unanticipated important role in epithelial barrier protection of the lower reproductive tract. Specifically, HA depletion in the cervix and vagina resulted in inappropriate differentiation of epithelial cells, increased epithelial and mucosal permeability, and strikingly increased preterm birth rates in a mouse model of ascending vaginal infection. Collectively, these findings revealed that although HA is not obligatory for cervical compliance, it is crucial for maintaining an epithelial and mucosal barrier to limit pathogen infiltration of the lower reproductive tract during pregnancy and thereby is protective against infection-mediated preterm birth.

Alterations in regulatory T cell subpopulations seen in preterm infants

Regulatory T cells are a population of CD4+ T cells that play a critical role in peripheral tolerance and control of immune responses to pathogens. The purpose of this study was to measure the percentages of two different regulatory T cells subpopulations, identified by the presence or absence of CD31 (Recent thymic emigrants and peripherally induced naïve regulatory T cells), in term and preterm infant cord blood. We report the association of prenatal factors, intrauterine exposure to lipopolysaccharide and inflammation and the percentages of these regulatory T cell subpopulations in term and preterm infants. Cord blood samples were collected from both term and preterm infants and mononuclear cells isolated over a Ficoll-Hypaque cushion. Cells were then stained with fluorochrome-labeled antibodies to characterize regulatory T cell populations and analyzed with multi-color flow cytometry. Cord blood plasma C-reactive protein, and lipopolysaccharide were also measured. Placental pathology was also examined. We report a gestational age-dependent difference in the percentage of total regulatory T cells, in which preterm infants of lower gestational ages have an increased percentage of regulatory T cells. We report the presence of two populations of regulatory T cells (CD31+ and CD31-) in cord blood of term and preterm infants and their association with different maternal and fetal characteristics. Factors associated with differences in the percentage of CD31- Tregs included the use of prenatal antibiotics, steroids and magnesium sulfate. In addition, the percentage of CD31- Tregs was significantly higher in cord blood of preterm pregnancies associated with inflammation and prenatal lipopolysaccharide exposure. The peripheral Treg pool of preterm infants could be altered by prenatal exposure to inflammation and chorioamnionitis; however, the clinical implications of this finding are not yet understood.