Altered immune function in human newborns after prenatal administration of betamethasone: enhanced natural killer cell activity and decreased T cell proliferation in cord blood

Urinary Tract Infection Epidemiology in NICUs in the United States

OBJECTIVE

 Our objective was to characterize the incidence, associated clinical factors, timing of infection, microbiology, and incidence of concordant blood culture of urinary tract infections (UTIs) in very low birth weight (VLBW <1,500g) infants.

STUDY DESIGN

 Multicenter observational cohort study of VLBW infants with gestational age (GA) ≤32 weeks, still hospitalized on postnatal day 7, and discharged 2010 to 2018 from Pediatrix Medical Group neonatal intensive care units. Demographic and clinical characteristics of infants with and without UTI were compared. Multivariable logistic regression evaluated adjusted odds of UTI diagnosis.

RESULTS

 Of 86,492 included infants, 5,988 (7%) had a UTI. The most common pathogen was Enterococcus spp. (20%), followed by Escherichia coli (19%) and Klebsiella spp. (18%). Candida spp. (6%) was the most common nonbacterial pathogen. Concordant-positive blood culture was present in 8% of infants with UTI diagnoses. UTI was associated with lower GA, male sex, vaginal delivery, prenatal steroid exposure, and longer duration of hospitalization.

CONCLUSION

 UTI is a common cause of infection in VLBW infants, especially among the smallest, most premature, male infants, and those with a longer duration of hospitalization. Neonatal clinicians should consider obtaining urine culture in the setting of late-onset sepsis evaluations in VLBW infants.

KEY POINTS

· UTI is a common cause of LOS in VLBW infants.. · The most common pathogens are Enterococcus spp. and E. coli.. · UTI risk varies among different VLBW infant populations.. · Next steps should include evaluation of preventative measures..

The monocyte-derived cytokine response in whole blood from preterm newborns against sepsis-related bacteria is similar to term newborns and adults

Introduction

Sepsis is characterized by a dysregulated innate immune response. It is a leading cause of morbidity and mortality in newborns, in particular for newborns that are born premature. Although previous literature indicate that the pro-inflammatory response may be impaired in preterm newborns, serum levels of monocyte-derived cytokines, such as TNF-α and IL-6, vary highly between newborns and can reach adult-like concentrations during sepsis. These contradictory observations and the severe consequences of neonatal sepsis in preterm newborns highlight the need for a better understanding of the pro-inflammatory cytokine response of preterm newborns to improve sepsis-related outcomes.

Methods and results

Using an in vitro model with multiple read outs at the transcriptional and protein level, we consistently showed that the monocyte-derived cytokine response induced by sepsis-related bacteria is comparable between preterm newborns, term newborns and adults. We substantiated these findings by employing recombinant Toll-like receptor (TLR) ligands and showed that the activation of specific immune pathways, including the expression of TLRs, is also similar between preterm newborns, term newborns and adults. Importantly, we showed that at birth the production of TNF-α and IL-6 is highly variable between individuals and independent of gestational age.

Discussion

These findings indicate that preterm newborns are equally capable of mounting a pro-inflammatory response against a broad range of bacterial pathogens that is comparable to term newborns and adults. Our results provide a better understanding of the pro-inflammatory response by preterm newborns and could guide the development of interventions that specifically modulate the pro-inflammatory response during sepsis in preterm newborns.

Antenatal Steroids and Cord Blood T-cell Glucocorticoid Receptor DNA Methylation and Exon 1 Splicing

Antenatal administration of glucocorticoids such as betamethasone (BMZ) during the late preterm period improves neonatal respiratory outcomes. However, glucocorticoids may elicit programming effects on immune function and gene regulation. Here, we test the hypothesis that exposure to antenatal BMZ alters cord blood immune cell composition in association with altered DNA methylation and alternatively expressed Exon 1 transcripts of the glucocorticoid receptor (GR) gene in cord blood CD4⁺ T-cells. Cord blood was collected from 51 subjects in the Antenatal Late Preterm Steroids Trial: 27 BMZ, 24 placebo. Proportions of leukocytes were compared between BMZ and placebo. In CD4+ T-cells, methylation at CpG sites in the GR promoter regions and expression of GR mRNA exon 1 variants were compared between BMZ and placebo. BMZ was associated with an increase in granulocytes (51.6% vs. 44.7% p = 0.03) and a decrease in lymphocytes (36.8% vs. 43.0% p = 0.04) as a percent of the leukocyte population vs. placebo. Neither GR methylation nor exon 1 transcript levels differed between groups. BMZ is associated with altered cord blood leukocyte proportions, although no associated alterations in GR methylation were observed.

The Effect of Antenatal Steroid Therapy on Early Inflammation Markers and Leukocyte Counts in Premature Infants

ObjectiveWe investigated the effect of antenatal steroid therapy(AST) on white blood cell (WBC) and neutrophil counts and the inflammatory markers C-reactive protein(CRP), interleukin 6(IL-6), interleukin 10(IL-10), and beta-2 microglobulin(ß2M) in preterm infants.Materials MethodNeonates born at ≤34 weeks of gestation and admitted at hospital between May and November 2018 were included. The neonates were divided into three groups based on AST dose administered: 24 mg betamethasone (full course), 12 mg betamethasone (incomplete course), and no AST. 170 infants were analyzed.ResultsOf these, 45.2% (n = 77) received a full course of AST, 38.8% (n = 66) received an incomplete course of AST, and 15.8% (n = 27) did not receive AST. WBC, CRP, IL-6, IL-10, and ß2M levels were similar between the three groups, whereas neutrophil count was significantly lower in full course AST group.ConclusionConsistent with the literature data, AST was associated with reduced neutrophil count but did not affect the other inflammatory markers studied.

Beyond Fetal Immunity: A Systematic Review and Meta-Analysis of the Association Between Antenatal Corticosteroids and Retinopathy of Prematurity

Background: Retinopathy of prematurity (ROP) is a major cause of childhood blindness. Antenatal corticosteroids (ACS) exposure is known to ameliorate the risk of and mortality of neonatal morbidities. However, the effect of ACS on ROP development is currently unknown. We conducted a meta-analysis with up-to-date evidence to assess the association between ACS exposure and the development of ROP in at-risk preterm infants.

Methods: PubMed, EMBASE, Scopus, Web of Science, and the Cochrane Library were systematically searched from inception to May 2021, supplemented with manual search from reference lists. Studies with a control group reporting ROP rate in ACS-exposed infants were included. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated utilizing a random-effects model. The Newcastle-Ottawa Scale was used for assessment of risk of bias in the included studies. Meta-regressions were performed to explore the predictive role of confounders for between-study variance.

Results: A total of 63 studies, involving 196,264 infants, were included. Meta-analysis showed ACS exposure was not associated with ROP occurrence (uOR 0.92, 95% CI 0.80–1.07; aOR 0.87, 95% CI 0.7–1.08). Results from extremely immature subgroups revealed significant reduced risks of ROP occurrence in ACS-exposed infants. ACS exposure was associated with significantly lower odds of ROP progression in adjusted analysis (aOR 0.48, 95% CI 0.26–0.89) instead of unadjusted analysis (uOR 0.86, 95% CI 0.68–1.08). Meta-regression showed birth weight and patent ductus arteriosus of the cohort were associated with ROP occurrence, sample size and study design strongly associated with ROP progression in ACS-exposed infants.

Conclusion: ACS treatment may decrease, but not prevent, the severity of ROP. Findings from severe ROP should be interpreted with caution owing to limited studies and the possibility of false-positive results. Considering the particular benefits in extremely immature infants, we recommend routine usage of ACS in mothers with threatened delivery to this particular birth cohort to prevent ROP occurrence. Future studies adjusting for major confounders are warranted to mitigate risk of bias in such observational evidence.

The Effects of Antenatal Steroid Treatment on Preterm Infants' Early Laboratory Analysis

Objectives

We assessed the effects of antenatal steroid treatment on preterm laboratory analysis conducted in the first 24 hours of life.

Methods

Medical records of inborn preterm infants whose gestational age was ≤32 weeks were retrospectively reviewed in this study. Preterm infants whose mothers received antenatal betamethasone treatment of either 12 mg or 24 mg and who did not were divided into two groups. Maternal and neonatal demographic characteristics, all preterm morbidities and mortality rates, early laboratory examinations were compared between the two groups.

Results

Medical records of 603 infants between 2008 and 2013 were retrospectively reviewed. Data from 515 infants were analyzed. Three hundred and four infants (n=304) were in the antenatal steroid treatment (AST) group and 211 infants were in the group that did not receive the treatment. The incidence of preeclampsia and oligohydramnios was significantly higher in the AST group. Intubation in the delivery room rates decreased in the AST group. APGAR scores at five minutes were significantly higher in the AST group. White blood counts (WBC) significantly decreased, whereas the platelet counts were higher in the AST group. Serum C-reactive protein (CRP) and Interleukin-6 (IL-6) levels did not differ between groups.

Conclusion

We did not demonstrate any relationship between inflammatory markers and antenatal steroid treatment in preterm infants.

Immune System Remodelling by Prenatal Betamethasone: Effects on β-Cells and Type 1 Diabetes

Type 1 diabetes (T1D) is a multifactorial disease of unknown aetiology. Studies focusing on environment-related prenatal changes, which might have an influence on the development of T1D, are still missing. Drugs, such as betamethasone, are used during this critical period without exploring possible effects later in life. Betamethasone can interact with the development and function of the two main players in T1D, the immune system and the pancreatic β-cells. Short-term or persistent changes in any of these two players may influence the initiation of the autoimmune reaction against β-cells. In this review, we focus on the ability of betamethasone to induce alterations in the immune system, impairing the recognition of autoantigens. At the same time, betamethasone affects β-cell gene expression and apoptosis rate, reducing the danger signals that will attract unwanted attention from the immune system. These effects may synergise to hinder the autoimmune attack. In this review, we compile scattered evidence to provide a better understanding of the basic relationship between betamethasone and T1D, laying the foundation for future studies on human cohorts that will help to fully grasp the role of betamethasone in the development of T1D.

Antenatal corticosteroid administration is associated with decreased growth of the fetal thymus: a prospective cohort study

OBJECTIVE

To examine the effect of antenatal corticosteroid administration (ACS) on fetal thymus growth in women who received ACS compared with gestational-age-matched controls.

STUDY DESIGN

Fetal thymus size and growth were measured in women at risk for preterm delivery who received ACS and compared with a matched cohort of women who were at low risk for preterm delivery and did not receive ACS. Fetal thymus perimeter and diameter were measured by 2-D ultrasound at baseline and every 2 weeks until delivery.

RESULTS

After adjusting for confounders, ACS exposure was associated with a significant reduction in thymus perimeter size (-0.70; 95% CI: -1.33, -0.07; P = 0.03). For every additional week of exposure, thymus growth trajectory was significantly decreased in ACS-exposed fetuses (P = 0.04).

CONCLUSION

The association between ACS and reduced fetal thymus growth should be further examined to establish the impact of ACS on childhood thymus development and immune programming.

Bronchopulmonary dysplasia: Pathophysiology and potential anti-inflammatory therapies

Inflammation of the preterm lungs is key to the pathogenesis of bronchopulmonary dysplasia (BPD), whether it arises as a consequence of intrauterine inflammation or postnatal respiratory management. This review explores steroidal and non-steroidal therapies for reducing neonatal pulmonary inflammation, aimed at treating or preventing BPD.

Prenatal Betamethasone interferes with immune system development and alters target cells in autoimmune diabetes

Non-genetic factors are crucial in the pathogenesis of type 1 diabetes (T1D), a disease caused by autoimmunity against insulin-producing β-cells. Exposure to medications in the prenatal period may influence the immune system maturation, thus altering self-tolerance. Prenatal administration of betamethasone –a synthetic glucocorticoid given to women at risk of preterm delivery– may affect the development of T1D. It has been previously demonstrated that prenatal betamethasone administration protects offspring from T1D development in nonobese diabetic (NOD) mice. The direct effect of betamethasone on the immature and mature immune system of NOD mice and on target β-cells is analysed in this paper. In vitro, betamethasone decreased lymphocyte viability and induced maturation-resistant dendritic cells, which in turn impaired γδ T cell proliferation and decreased IL-17 production. Prenatal betamethasone exposure caused thymus hypotrophy in newborn mice as well as alterations in immune cells subsets. Furthermore, betamethasone decreased β-cell growth, reduced C-peptide secretion and altered the expression of genes related to autoimmunity, metabolism and islet mass in T1D target tissue. These results support the protection against T1D in the betamethasone-treated offspring and demonstrate that this drug alters the developing immune system and β-cells. Understanding how betamethasone generates self-tolerance could have potential clinical relevance in T1D.

Dichotomous development of the gut microbiome in preterm infants

BACKGROUND

Preterm infants are at risk of developing intestinal dysbiosis with an increased proportion of Gammaproteobacteria. In this study, we sought the clinical determinants of the relative abundance of feces-associated Gammaproteobacteria in very low birth weight (VLBW) infants. Fecal microbiome was characterized at ≤ 2 weeks and during the 3rd and 4th weeks after birth, by 16S rRNA amplicon sequencing. Maternal and infant clinical characteristics were extracted from electronic medical records. Data were analyzed by linear mixed modeling and linear regression.

RESULTS

Clinical data and fecal microbiome profiles of 45 VLBW infants (gestational age 27.9 ± 2.2 weeks; birth weight 1126 ± 208 g) were studied. Three stool samples were analyzed for each infant at mean postnatal ages of 9.9 ± 3, 20.7 ± 4.1, and 29.4 ± 4.9 days. The average relative abundance of Gammaproteobacteria was 42.5% (0-90%) at ≤ 2 weeks, 69.7% (29.9-86.9%) in the 3rd, and 75.5% (54.5-86%) in the 4th week (p < 0.001). Hierarchical and K-means clustering identified two distinct subgroups: cluster 1 started with comparatively low abundance that increased with time, whereas cluster 2 began with a greater abundance at ≤ 2 weeks (p < 0.001) that decreased over time. Both groups resembled each other by the 3rd week. Single variants of Klebsiella and Staphylococcus described variance in community structure between clusters and were shared between all infants, suggesting a common, hospital-derived source. Fecal Gammaproteobacteria was positively associated with vaginal delivery and antenatal steroids.

CONCLUSIONS

We detected a dichotomy in gut microbiome assembly in preterm infants: some preterm infants started with low relative gammaproteobacterial abundance in stool that increased as a function of postnatal age, whereas others began with and maintained high abundance. Vaginal birth and antenatal steroids were identified as predictors of Gammaproteobacteria abundance in the early (≤ 2 weeks) and later (3rd and 4th weeks) stool samples, respectively. These findings are important in understanding the development of the gut microbiome in premature infants.

Analysis of PD-1 expression in the monocyte subsets from non-septic and septic preterm neonates

Programmed death-1 (PD-1) receptor system represents a part of recently reported immunoregulatory pathway. PD-1 is an immune checkpoint molecule, which plays an important role in downregulating the immune system proinflammatory activity. Until recently, PD-1 expression was not established on immune cells of the preterm infants. The study objectives were to confirm expression of the PD-1 receptors on the monocytes isolated from very low birth weight newborns (VLBW), and to analyze their expression during the first week of life and late-onset sepsis. Peripheral blood mononuclear cells were isolated from 76 VLBW patients without early-onset sepsis on their 5^th day of life (DOL). PD-1 expression was determined on the monocyte subsets (classical, intermediate, non-classical) by flow cytometry. In case of late-onset sepsis (LOS), the same analysis was performed. Our results demonstrated that on the 5^th DOL, PD-1 receptors were present in all the monocyte subsets. Children, whose mothers had received antenatal steroids, presented higher absolute numbers of non-classical monocytes with PD-1 expression. Infants born extremely preterm who later developed LOS, initially showed a lower percentage of PD-1 receptor-positive intermediate monocytes in comparison to neonates born very preterm. During LOS, we observed a rise in the percentage of classical monocytes with PD-1 expression. In case of septic shock or fatal outcome, there was a higher percentage and absolute count of intermediate monocytes with PD-1 expression in comparison to children without these complications. In conclusion, monocytes from VLBW children express PD-1 receptors. Antenatal steroid administration seems to induce PD-1 receptor expression in the non-classical monocytes. PD-1 might play a role in immunosuppressive phase of sepsis in the prematurely born children with septic shock and fatal outcome.

Antenatal glucocorticoids and neonatal inflammation-associated proteins

BACKGROUND

To date, studies of the relationship between antenatal glucocorticoids (AGC) and neonatal inflammation in preterm newborns have been largely limited to umbilical cord blood specimens.

AIM

To explore the association between exposure to antenatal glucocorticoids and concentrations of inflammation-related proteins in whole blood collected from very preterm newborns at multiple times during the first postnatal month.

METHODS

We measured the protein concentrations on postnatal day 1 (N=1118), day 7 (N=1138), day 14 (N=1030), day 21 (N=936) and day 28 (N=877) from infants born before the 28th week of gestation and explored the relationship between antenatal steroid receipt and protein concentrations in the highest and lowest quartiles. The creation of multinomial logistic regression models (adjusted for potential confounders) allowed us calculate odds ratios and 95% confidence intervals.

RESULTS

Twenty of 420 assessments [21 (proteins)×2 (exposure levels: partial and full)×2 (quartile levels: top and bottom)×5 (days)] were statistically significant without any cohesive pattern.

CONCLUSION

Among infants born before 28 weeks of gestational age, neither full, nor partial courses of antenatal glucocorticoids have a sustained anti-inflammatory effect.

Lymphocyte subpopulations in premature infants: an observational study

BACKGROUND AND OBJECTIVES

The infant's immune system evolves over the first months and years of life. Strong correlation exists between lymphocyte count, lymphocyte subpopulations and gestational age at birth. Associations with antenatal and postnatal steroid treatment, infection and chronic lung disease have also been described. Few published studies report the effect of increasing postnatal age (PNA) and comorbidities on lymphocyte subpopulations in premature infants beyond the first 4 months of life. This study aimed to describe changes in lymphocyte subpopulations in preterm infants up to 13 months PNA.

METHODS

Premature infants (23-34 weeks completed gestation) from five centres had lymphocyte subpopulations measured at 2, 5 or 7, 12 and 13 months PNA alongside their vaccine responses in a vaccination trial.

RESULTS

393 blood samples from 151 babies were analysed. There was an increase in absolute numbers of total lymphocytes (median cell count 6.21×10⁹/L at 13 months compared with 4.9×10⁹/L at 2 months PNA) and CD3⁺, CD4⁺, CD8⁺, natural killer and B cells with increasing age. At 2 months PNA, there was a positive correlation between gestation and CD3⁺ and CD4⁺ counts (r=0.32 and 0.46, respectively) and proportions (r=0.22 and 0.41, respectively), and CD4⁺:CD8⁺ ratios (r=0.57), but a negative correlation with CD8⁺ proportions (r=-0.32).

CONCLUSIONS

This longitudinal study describes the distribution of lymphocyte subpopulations in premature infants and provides reference ranges for the major lymphocyte subsets to help guide clinicians when assessing premature infants for immunodeficiency in the first year of life.

TRIAL REGISTRATION NUMBER

EudraCT 2007-007535-23.

[Effect of perinatal factors on postnatal development of lymphocyte subsets in early preterm infants]

OBJECTIVE

To study the postnatal changes in lymphocyte subsets in early preterm infants and the effect of perinatal factors on lymphocyte subsets.

METHODS

A total of 61 early preterm infants were enrolled. Flow cytometry was used to measure the absolute counts of lymphocytes and lymphocyte subsets at 1, 7, 14, and 28 days after birth, as well as at 6 months after birth for 17 of these early preterm infants. The effects of perinatal factors, such as antepartum use of hormone, intrauterine infection, gestational age at birth, and Ureaplasma urealyticum (UU) colonization, on lymphocyte subsets were analyzed.

RESULTS

The absolute counts of lymphocyte subsets except natural killer (NK) cells were lowest at birth, increased rapidly at 1 week after birth, and reached the levels in healthy infants at 6 months; the count of NK cells remained at a low level and increased significantly at 6 months after birth. Compared with those with a gestational age of <28 weeks, the early preterm infants with a gestational age of ≥28 weeks had significantly higher absolute counts of T cells, T helper (Th) cells, and NK cells at 7 days after birth, a significantly higher absolute count of T cells at 14 days after birth, and significantly higher absolute counts of lymphocytes and Th cells at 28 days after birth (P<0.05). Compared with the group not using hormone, the group using hormone showed a significantly higher absolute count of T cells at 7 days after birth and significantly higher absolute counts of lymphocytes and all subsets at 14 days after birth (P<0.05). There was no significant difference in lymphocyte subsets at 1 day after birth between the intrauterine infection and non-infection groups (P>0.05); the intrauterine infection group had significantly higher absolute counts of B cells at 7 and 14 days after birth than the non-infection group. Compared those without UU colonization, the infants with UU colonization had significantly higher absolute counts of lymphocytes, T cells, Th cells, and Ts cells at 1 day after birth and a significantly higher absolute count of B cells at 14 days after birth.

CONCLUSIONS

Early preterm infants have deficiencies in innate immune cells at birth and normal levels at about 6 months after birth. Various perinatal factors including antepartum use of hormone, gestational age at birth, intrauterine infection, and UU colonization have long-term effects on lymphocyte subsets in early preterm infants.

The effect of Indomethacin and Betamethasone on the cytokine response of human neonatal mononuclear cells to gram-positive bacteria

Intrauterine infections with gram-positive bacteria pose a serious threat to neonates since they can result in neonatal sepsis, induce a fetal inflammatory response and also cause preterm birth. Despite intensive care, prematurity remains a leading cause of neonatal death, and is often accompanied by a number of morbidities. In order to prevent premature birth, tocolytic agents like Indomethacin are administered. Betamethasone is used to promote lung maturation and prevent respiratory distress syndrome. A combination of both drugs is assumed to prevent premature delivery while simultaneously facilitating lung maturation. This study investigates the effect of Betamethasone, Indomethacin and a combination of both on the cytokine production of neonatal cord blood mononuclear cells (CBMC) after stimulation with lysates of the gram-positive pathogens Streptococcus agalactiae and Enterococcus faecalis. The aim of the study is to determine the impact of these drugs on the function of the neonatal immune system which should aid clinicians in choosing the optimal therapy in case of preterm birth associated with intrauterine infection. Betamethasone reduced the production of the pro-inflammatory cytokines IL-6, IL-12p40, MIP-1α and TNF and increased the expression of the anti-inflammatory cytokine IL-10, depending on the pathogen used for stimulation. In contrast to Betamethasone, Indomethacin almost exclusively increased IL-10 production. The combination of both drugs decreased the expression of IL-6, IL-12p40, MIP-1α and TNF while increasing IL-10 production, depending on the concentration of Indomethacin and the pathogen used for stimulation. Based on our results, the combination therapy with Indomethacin and Betamethasone has a similar effect on cytokine production as Betamethasone alone, which is generally administered in case of impending preterm birth. However, the combination therapy has the advantage of promoting lung maturation while simultaneously blocking preterm labor effectively.

Prenatal dexamethasone exposure in rats results in long-term epigenetic histone modifications and tumour necrosis factor-α production decrease

Glucocorticoid (GC) is often given when preterm delivery is expected. This treatment is successful in stimulating the development of the fetal lung. However, reports and related research regarding the prolonged effects of prenatal GC on the development of immunity are very limited. Some data, derived from infants whose mothers were given immunosuppressants during pregnancy for the treatment of autoimmune disorders, suggest that prenatal exposure to GC may have only a limited effect on the development of the immune system. What is unknown is whether the immune modulation effects of prenatal GC might appear at a later childhood stage and beyond. Here we evaluated the immune programming influenced by prenatal GC. Pregnant Sprague-Dawley rats received dexamethasone (DEX; 0.1 mg/kg/day) or saline at gestational days 14-20. Male offspring were killed at day 7 or day 120 after birth. Spleens were collected for immune study. Of the inflammation mediators, matrix metalloproteinase-9, tumour necrosis factor-α (TNF-α) and granulocyte-macrophage colony-stimulating factor mRNAs decreased in the prenatal DEX group at an early stage after birth. Upon concanavalin A stimulation, prenatal DEX treatment reduced TNF-α production, but not interferon-γ production, by splenocytes at day 120 after birth compared with the vehicle group. Decreased levels of active chromatin signs (acetylation of histone H3 lysines, H3K4me1/3, and H3K36me3) in TNF-α promoter were compatible with the expressions of TNF-α. Our results suggest that prenatal DEX has a profound and lasting impact on the developing immune system even to the adult stage. Epigenetic histone modifications regulate TNF-α expression following prenatal DEX in rats.

Prenatal adverse life events increase the risk for atopic diseases in children, which is enhanced in the absence of a maternal atopic predisposition

BACKGROUND

There is evidence to suggest an association between prenatal maternal stress and the development of asthma or other atopic diseases in offspring. Yet, insights on the lasting effect of multiple, common prenatal stressors are rare, and the effects of prenatal timing are poorly understood. Further, it remains elusive if prenatal life events modify the risk for atopic diseases in the context of a parental predisposition to atopy.

OBJECTIVE

We tested whether women's experiences of common, adverse life events during the first or second half of pregnancy predicted the risk of developing atopic diseases in their children and whether a reported parental atopic disease moderated this association.

METHODS

We calculated the odds of a child developing asthma, eczema, and/or allergic rhinitis at ages 6 or 14 years, depending on maternal prenatal exposure to negative life events in a sample of 1587 children from the Western Australian Pregnancy Cohort (Raine) Study by using multivariable logistic regression.

RESULTS

We observed that the likelihood of asthma and eczema at age 14 years was significantly increased in children of mothers who had experienced adverse life events during the second half of gestation (1 life event: adjusted odds ratio for asthma, 2.08 [95% CI, 1.22-3.54]). A stronger increase in the odds to develop asthma upon prenatal life events was present in children of mothers without asthma compared with mothers with asthma.

CONCLUSIONS

Maternal adverse life events during the second half of gestation are linked to an increased risk for the development of atopic disorders, asthma, and eczema, in the case of asthma, particularly in the absence of a maternal asthma.

Hierarchical maturation of innate immune defences in very preterm neonates

BACKGROUND

Preterm neonates are highly vulnerable to infection.

OBJECTIVES

To investigate the developmental contribution of prematurity, chorioamnionitis and antenatal corticosteroids (ANS) on the maturation of neonatal microbial pathogen recognition responses.

METHODS

Using standardized protocols, we assayed multiple inflammatory cytokine responses (IL-1β, IL-6, TNF-α and IL-12/23p40) to three prototypic Toll-like receptor (TLR) agonists, i.e. TLR4 (lipopolysaccharide), TLR5 (flagellin) and TLR7/8 (R848), and to the non-TLR retinoic acid-inducible gene I (RIG-I)-like receptor agonist, in cord blood mononuclear cells from neonates born before 33 weeks of gestation and at term.

RESULTS

TLR responses develop asynchronously in preterm neonates, whereby responses to TLR7/8 were more mature and were followed by the development of TLR4 responses, which were also heterogeneous. Responses to TLR5 were weakest and most immature. Maturity in TLR responses was not influenced by sex. Overall, we detected no significant contribution of ANS and chorioamnionitis to the developmental attenuation of either TLR or RIG-I responses.

CONCLUSIONS

The maturation of anti-microbial responses in neonates born early in gestation follows an asynchronous developmental hierarchy independently of an exposure to chorioamnionitis and ANS. Our data provide an immunological basis for the predominance of specific microbial infections in this age group.

Effect of prenatal steroid treatment on the developing immune system

Prenatal steroids have an undisputed positive effect of decreasing neonatal morbidity and mortality by improving fetal lung maturation. Some concerns have been raised on long-term consequences on the hypothalamic-pituitary-adrenal axis and cognition, but there are no studies addressing effects on the immune system. The thymus is an essential organ for the development and selection of T cells, and thymocytes are extremely sensitive to steroids. Using a mouse model for prenatal steroid administration, we show here that betamethasone treatment to the mother has a profound effect on the thymus of the offspring. We find the thymus volume reduced, affecting mostly the developing CD4+ CD8+ double-positive thymocytes and a compensatory accelerated transition of the earlier stages to replenish the depleted compartment. This effect lasts for at least 3 days, which correspond to a very relevant period for the selection of the T cell repertoire. Moreover, we show that low doses of betamethasone have similar effects on human thymocytes in vitro. Therefore, further studies are needed to analyze possible long-term consequences of this treatment on the immune system of the offspring.

KEY MESSAGE

Betamethasone administered to the mother before birth reaches the fetal thymus. Prenatal betamethasone results in massive loss of developing thymocytes. The effects of betamethasone on thymus development are visible for several days. Human thymocytes are also sensitive to low doses of betamethasone. Altered thymocyte development around birth may have an effect on the immune system.

The immune consequences of preterm birth

Preterm birth occurs in 11% of live births globally and accounts for 35% of all newborn deaths. Preterm newborns have immature immune systems, with reduced innate and adaptive immunity; their immune systems may be further compromised by various factors associated with preterm birth. The immune systems of preterm infants have a smaller pool of monocytes and neutrophils, impaired ability of these cells to kill pathogens, and lower production of cytokines which limits T cell activation and reduces the ability to fight bacteria and detect viruses in cells, compared to term infants. Intrauterine inflammation is a major contributor to preterm birth, and causes premature immune activation and cytokine production. This can induce immune tolerance leading to reduced newborn immune function. Intrauterine inflammation is associated with an increased risk of early-onset sepsis and likely has long-term adverse immune consequences. Requisite medical interventions further impact on immune development and function. Antenatal corticosteroid treatment to prevent newborn respiratory disease is routine but may be immunosuppressive, and has been associated with febrile responses, reductions in lymphocyte proliferation and cytokine production, and increased risk of infection. Invasive medical procedures result in an increased risk of late-onset sepsis. Respiratory support can cause chronic inflammatory lung disease associated with increased risk of long-term morbidity. Colonization of the infant by microorganisms at birth is a significant contributor to the establishment of the microbiome. Caesarean section affects infant colonization, potentially contributing to lifelong immune function and well-being. Several factors associated with preterm birth alter immune function. A better understanding of perinatal modification of the preterm immune system will allow for the refinement of care to minimize lifelong adverse immune consequences.

The fetal inflammatory response in subgroups of women with preterm prelabor rupture of the membranes

OBJECTIVE

To evaluate the influence of microbial invasion of the amniotic cavity (MIAC) and histological chorioamnionitis (HCA) on the intensity of the fetal inflammatory response and the occurrence of fetal inflammatory response syndrome (FIRS) in preterm prelabor rupture of membranes (PPROM).

METHODS

One hundred and forty-nine women with singleton pregnancies complicated by PPROM between the gestational ages 24 + 0 and 36 + 6 weeks were included in the study. Blood samples were obtained by venipuncture from the umbilical cord after the delivery of the newborn. The umbilical cord blood interleukin (IL)-6 levels were evaluated using ELISA kits. The fetal inflammatory response was determined by IL-6 levels, and FIRS was defined as an umbilical cord blood IL-6 >11 pg/mL.

RESULT

IL-6 levels and the occurrence of FIRS were higher in women complicated with both MIAC and HCA (median IL-6 35.5 pg/mL, FIRS in 68%) than in women with HCA alone (median IL-6 5.8 pg/mL, FIRS in 36%), MIAC alone (median IL-6 2.8 pg/mL, FIRS in 17%) or women without MIAC or HCA (median IL-6 4.3 pg/mL, FIRS in 29%). There were no differences in IL-6 levels or rates of FIRS among women with MIAC alone or HCA alone and women without both MIAC and HCA.

CONCLUSION

A higher fetal inflammatory response mediated by umbilical cord blood IL-6 was identified when both MIAC and HCA were detected in pregnancies complicated by PPROM.

Ovine fetal thymus response to lipopolysaccharide-induced chorioamnionitis and antenatal corticosteroids

Rationale

Chorioamnionitis is associated with preterm delivery and involution of the fetal thymus. Women at risk of preterm delivery receive antenatal corticosteroids which accelerate fetal lung maturation and improve neonatal outcome. However, the effects of antenatal corticosteroids on the fetal thymus in the settings of chorioamnionitis are largely unknown. We hypothesized that intra-amniotic exposure to lipopolysaccharide (LPS) causes involution of the fetal thymus resulting in persistent effects on thymic structure and cell populations. We also hypothesized that antenatal corticosteroids may modulate the effects of LPS on thymic development.

Methods

Time-mated ewes with singleton fetuses received an intra-amniotic injection of LPS 7 or 14 days before preterm delivery at 120 days gestational age (term = 150 days). LPS and corticosteroid treatment groups received intra-amniotic LPS either preceding or following maternal intra-muscular betamethasone. Gestation matched controls received intra-amniotic and maternal intra-muscular saline. The fetal intra-thoracic thymus was evaluated.

Results

Intra-amniotic LPS decreased the cortico-medullary (C/M) ratio of the thymus and increased Toll-like receptor (TLR) 4 mRNA and CD3 expression indicating involution and activation of the fetal thymus. Increased TLR4 and CD3 expression persisted for 14 days but Foxp3 expression decreased suggesting a change in regulatory T-cells. Sonic hedgehog and bone morphogenetic protein 4 mRNA, which are negative regulators of T-cell development, decreased in response to intra-amniotic LPS. Betamethasone treatment before LPS exposure attenuated some of the LPS-induced thymic responses but increased cleaved caspase-3 expression and decreased the C/M ratio. Betamethasone treatment after LPS exposure did not prevent the LPS-induced thymic changes.

Conclusion

Intra-amniotic exposure to LPS activated the fetal thymus which was accompanied by structural changes. Treatment with antenatal corticosteroids before LPS partially attenuated the LPS-induced effects but increased apoptosis in the fetal thymus. Corticosteroid administration after the inflammatory stimulus did not inhibit the LPS effects on the fetal thymus.

Impaired neuroendocrine and immune response to acute stress in medication-naive patients with a first episode of psychosis

Little is known about how the biological stress response systems--the autonomic nervous system (ANS), the hypothalamic-pituitary-adrenal (HPA) axis, and the immune system--function during psychosis. Results of studies on the effect of stress on the immune and autonomic system in patients with schizophrenia are inconsistent. The present study investigates whether the stress response is impaired in medication-naive patients with a first episode of psychosis. Ten male patients with a first episode of psychosis and 15 controls were exposed to the stress of public speaking. Parameters of the ANS (heart rate and catecholamines), the HPA axis (plasma adrenocorticotropic hormone [ACTH] and cortisol), and the immune system (number and activity of natural killer [NK] cells) were measured. Peak responses were calculated to examine the relationship between stress-induced activation of the different systems. Subjective stress and anxiety before and during the task were assessed. Patients and controls displayed similar autonomic responses to acute stress. However, there was an impaired HPA axis response, slow onset and return of ACTH, and flattened cortisol response and a reduced increase in number NK cells and NK cell activity in patients with a first episode of psychosis. Furthermore, in patients, the relationship between the different stress response systems was weaker or absent compared with controls. These findings indicate that impairments in stress processing are associated with the endophenotype of psychosis and are not a result of illness progression or antipsychotic medication.

Inhaled glucocorticoids during pregnancy and offspring pediatric diseases: a national cohort study

RATIONALE

Glucocorticoid inhalation is the preferred asthma treatment during pregnancy. Previous studies on its safety focused on obstetric outcomes and offspring malformations.

OBJECTIVES

To determine whether glucocorticoid inhalation during pregnancy is a risk factor for offspring pediatric diseases.

METHODS

We studied offspring (live singletons) of pregnant women suffering from asthma during pregnancy (prevalence = 6.3%; n = 4,083 mother-child pairs) from the Danish National Birth Cohort (births, 1996-2002; prospective data). We estimated the associations between use of inhaled glucocorticoids for asthma treatment during pregnancy (n = 1231; 79.9% budesonide, 17.6% fluticasone, 5.4% beclomethasone, and 0.9% other or unspecified glucocorticoids) and offspring diseases (International Classification of Diseases-10th Revision, diagnoses) during childhood. We conducted Cox or logistic regression analyses for each International Classification of Diseases-10th Revision category, controlling for use of non-glucocorticoid-containing inhalants, and confirmed results by addressing confounding by treatment indication using propensity score.

MEASUREMENTS AND MAIN RESULTS

Offspring median age at end of follow-up was 6.1 (range, 3.6-8.9) years. Glucocorticoid inhalation was not associated with offspring disease risk in most categories, except for offspring endocrine, metabolic, and nutritional disorders (hazard ratio, 1.84; 95% confidence interval, 1.13-2.99). When repeating analyses with the major subgroup that used budesonide only, association estimates were of similar magnitude.

CONCLUSIONS

Regarding most disease categories, data are reassuring, supporting the use of inhaled glucocorticoids during pregnancy. In line with animal data, glucocorticoid inhalation during pregnancy may be a risk factor for offspring endocrine and metabolic disturbances, which should be considered further.

Association of antenatal steroid use with cord blood immune biomarkers in preterm births

OBJECTIVES

To evaluate the effect of maternal administration of antenatal steroids (ANS) on cord blood cytokine levels at birth in preterm infants.

METHODS

Cord blood cytokine concentrations were measured for pro-inflammatory cytokines (IL-1β, IL-6, and IL-8); anti-inflammatory cytokines (IL-4, IL-10 and TGF-β); and neurotrophic cytokines (BDNF, NT-3, and NT-4) in two hundred preterm infants. Data were analyzed using multivariable linear regression to model the independent and joint effects of ANS and inflammation on mean log cord blood cytokine concentrations adjusted for gestational age and Apgar scores.

RESULTS

Exposure to ANS had no significant effect on the cord blood concentrations of cytokines measured in this study. All three pro-inflammatory cytokine levels and levels of IL-10 were significantly increased and cord blood levels of TGF-β and NT-3 were significantly decreased in infants with placental inflammation.

CONCLUSION

Although exposure to ANS did not have any significant effect on cord blood levels of cytokines, there was a trend toward the attenuation of inflammatory response and higher levels of neurotrophic cytokines in infants born to mothers with placental inflammation and exposure to ANS compared to infants born to mothers with placental inflammation and no ANS exposure.

Development of lymphocyte subpopulations in preterm infants

In preterm neonates the immune system is thought to be less developed at birth, but very little is known about the actual size of lymphocyte subpopulations, and even less about the maturation of these subpopulations during the first months after a premature birth. To evaluate the development of lymphocyte subpopulations in preterm infants during the first 3 months after birth, we performed a prospective longitudinal study in two hospitals in the Netherlands. Preterm neonates (n = 38) of all post-menstrual ages were included and blood samples were taken from cord blood, and at 1 week, 6 weeks, and 3 months. Lymphocyte subpopulations were measured by four-colour flow cytometry. The data were compared with follow-up data obtained in healthy term neonates (n = 8), and with single samples from school age children (n = 5) and adults (n = 5). Overall, we found a similar pattern of post-natal development of lymphocyte subpopulations in the term and preterm infants. Both B lymphocytes and helper and cytotoxic T lymphocytes mainly consist of naive cells at birth and during the 3 months of follow-up in all neonatal age groups. So, the preterm immune system seems to be able to generate an outburst of naive T and B lymphocytes from the thymus and bone marrow within the same time span after the start of post-natal antigenic stimulation from the environment as the term immune system, but, with lower post-menstrual age, the absolute counts of naive helper T lymphocytes are lower.

Effects of intrauterine exposure to synthetic glucocorticoids on fetal, newborn, and infant hypothalamic-pituitary-adrenal axis function in humans: a systematic review

BACKGROUND

Synthetic glucocorticoids are commonly used in reproductive medicine. Fetal organ systems are highly sensitive to changes in the intrauterine environment, including overexposure to glucocorticoids. Structural and functional alterations resulting from such changes may persist throughout life and have been associated with diverse diseases. One system that could be particularly sensitive to fetal glucocorticoid overexposure is the hypothalamic-pituitary-adrenal (hpa) axis. Many human studies have investigated this possibility, but a systematic review to identify consistent, emergent findings is lacking.

METHODS

We systematically review 49 human studies, assessing the effects of intrauterine exposure to synthetic glucocorticoids on fetal, neonate, and infant hpa function.

RESULTS

Study quality varied considerably, but the main findings held true after restricting the analyses to higher-quality studies: intrauterine exposure to synthetic glucocorticoids reduces offspring hpa activity under unstimulated conditions after pain but not pharmacological challenge. Although reduced unstimulated hpa function appears to recover within the first 2 wk postpartum, blunted hpa reactivity to pain is likely to persist throughout the first 4 months of life. There is some evidence that the magnitude of the effects is correlated with the total amount of glucocorticoids administered and varies with the time interval between glucocorticoid exposure and hpa assessment.

CONCLUSIONS

This systematic review has allowed the demonstration of the way in which intrauterine exposure to various regimens of synthetic glucocorticoids affects various forms of hpa function. As such, it guides future studies in terms of which variables need to be focused on in order to further strengthen the understanding of such therapy, whilst continuing to profit from its clinical benefits.

NK cell increase in neonates from the preterm to the full-term period of gestation

BACKGROUND

Several studies have reported differences in lymphocyte phenotype in preterm and full-term neonates as compared to children and adults. However, a detailed description of the immunologic cell populations of neonates corresponding to the gestational age is needed. This will be helpful for clinical practice to find the best way to prevent neonatal infections or strengthen the immune system of newborns with some kind of immunodeficiency.

OBJECTIVE

To study maturation of the immune system throughout gestation, describing the variations of the lymphocyte populations in function of the gestational week when born.

METHODS

We performed a descriptive study in 134 healthy newborns (gestation age 25-42 weeks), quantifying the relative and absolute counts of cell populations in umbilical cord blood obtained during delivery, by a four-color flow cytometry single platform.

RESULTS

We first compared the very-preterm (25-30 weeks), preterm (31-36 weeks) and full-term (37-42 weeks) neonates. We found higher absolute counts of all cell populations in the full-term group and lower absolute and relative values of NK cells in the very-preterm group. After that, we analyzed the lymphocyte populations week to week (from week 31 to 41) and found the lowest values of T cells (CD4+ and CD8+) for week 36. However, lower percentages of CD4+ T cells and higher percentages of NK cells were observed in week 38 and 41.

CONCLUSION

We found an increase in cord blood NK cells with gestational age, both in terms of absolute counts and of percentage values. Moreover, the %NK cells showed a pattern opposite to %CD4+ T cells along the studied period.

Lymphocyte subsets in term and significantly preterm UK infants in the first year of life analysed by single platform flow cytometry

This observational study describes the ranges observed for lymphocyte subsets for significantly preterm infants (<32 weeks) in the first year of life, measured by single platform flow cytometry and compared to identically determined subsets in term infants. After ethical approval 39 term and 28 preterm infants had lymphocyte subset analysis before and after their primary immunization series. Median values with 5th and 95th percentiles of absolute counts and percentages are presented for total lymphocytes, T cells, NK cells, B cells, cytotoxic T cells, helper T cells, dual positive T cells, activated T cells, activated T helper cells (including T regulatory cells), pan memory T cells, pan naive T cells, memory helper T cells, naive helper T cells and the T helper/suppressor ratio. The lymphocyte profile of the preterm infants differed from that of the term infants.

Short-term (0-48 h) effects of maternal betamethasone administration on fetal heart rate and its variability

The short-term (0-48 h) effects of maternal betamethasone administration on computerized fetal heart rate (FHR) parameters were studied in 36 pregnancies at increased risk for preterm delivery. FHR was recorded for 90 min immediately before the start of betamethasone treatment and again at 6-h intervals during the next 48 h. Multiple linear regression models were used to assess the possible effects on FHR parameters of gestational age, time of day, clinical indication for treatment, and use of tocolytic drugs. Within 12 h after the start of treatment, significant increases occurred in FHR accelerations, and short- and long-term FHR variability (36%, 28%, and 22%, respectively), whereas basal FHR showed a 5% decrease. FHR variability was decreased by 10% at 42-48 h. The observed changes were more pronounced in older (29-33 wk of gestation) compared with younger fetuses (25-28 wk of gestation). Decelerations occurred only in 4 out of 11 compromised fetuses during betamethasone therapy. We conclude that there are significant changes in FHR parameters during the first 48 h after betamethasone administration. These changes are transient in normal fetuses. However, the compromised fetus may be adversely affected by betamethasone.

Administration of prenatal betamethasone suppresses the adrenal-hypophyseal axis in newborns with congenital diaphragmatic hernia

BACKGROUND

Congenital diaphragmatic hernia (CDH) is a condition that is characterized by pulmonary hypoplasia and pulmonary hypertension. Prenatal betamethasone often is administered to fetuses with CDH to improve pulmonary function. In this study, the authors investigate the possible role of the adrenal-hypophyseal axis in CDH in an animal model and subsequently in human infants with CDH.

METHODS

Twin fetal sheep underwent creation of DH or a sham thoracotomy, and levels of plasma and lung ACTH and plasma cortisol were compared. For the human studies, plasma levels of ACTH, cortisol, and DHEA were measured in cord blood samples collected from 9 CDH (5 that received prenatal betamethasone) and compared with those of 14 normal newborns. In both studies, ACTH and cortisol levels were determined by radioimmunoassay (RIA). Human (DHEA) levels were determined by ELISA.

RESULTS

Plasma ACTH and cortisol levels were elevated in fetal DH sheep compared with sham-operated controls; however, levels of ACTH in lung tissues were not different. Human newborns with CDH who have been exposed to prenatal steroids have significantly lower plasma ACTH, cortisol, and DHEA levels than normal newborns and CDH newborns not exposed to prenatal betamethasone.

CONCLUSIONS

In an ovine model of CDH, the adrenal-hypophyseal axis appears up-regulated in DH fetuses compared with sham-operated animals. Conversely, the adrenal-hypophyseal axis in human CDH newborns appears normal but is suppressed by the administration of prenatal betamethasone.

Antenatal betamethasone changes cord blood monocyte responses to endotoxin in preterm lambs

Corticosteroids are routinely administered to women at risk for preterm delivery to induce fetal lung maturation. Antenatal corticosteroids have immunomodulatory effects on fetal immune cells that are poorly understood. We hypothesized that maternal betamethasone would alter in fetal monocytes both the initiation of inflammation in response to pro-inflammatory stimuli and the resolution of inflammation by phagocytosis of apoptotic neutrophils. Preterm lambs at 124 d gestation were delivered 15 h, 1 d, 2 d, or 7 d after 0.5 mg/kg maternal intramuscular betamethasone. Monocytes from cord blood were isolated and cultured and results were compared with monocytes from preterm lambs exposed to maternal saline or monocytes from adult sheep. Phagocytosis of Escherichia coli was not changed, however, phagocytosis of apoptotic neutrophils was low in fetal monocytes but increased after 7 d exposure to maternal betamethasone to the level found in adult monocytes. Hydrogen peroxide production after endotoxin stimulus was significantly reduced to 7.1 +/- 2.2 micromol at 5 h, 8.7 +/- 2.9 micromol at 24 h, and 4.1 +/- 1.9 micromol at 48 h versus 16.4 +/- 3.6 micromol in control animals; at 7 d, the hydrogen peroxide production increased to 74.3 +/- 19.7 micromol (p < 0.05, per 10(6) monocytes). IL-6 production was reduced at 15 h after maternal betamethasone but at no other time point. Maternal betamethasone initially suppressed several fetal monocyte functions, however, at 7 d, measurements of initiation and resolution of inflammation were increased to levels similar to monocytes from adult sheep. The time-dependent changes in maternal betamethasone modulation of the responses of fetal monocytes may influence immune function of the preterm lamb after delivery.

Neonates born to pre-eclamptic mothers have a higher percentage of natural killer cells (CD3-/CD56+16+) in umbilical cord blood than those without pre-eclampsia

OBJECTIVE

Maternal endothelial dysfunction and intravascular inflammation have been implicated in the mechanisms of disease responsible for the clinical syndrome of pre-eclampsia. Recently, the activation of the innate limb of the immune response (neutrophils and monocytes) in the fetal circulation has been reported in neonates born to mothers with pre-eclampsia. Natural killer (NK) cells are identified morphologically as a subpopulation of lymphocytes, but functionally as one component of the innate immune system. NK cells participate in the control of viral or bacterial infection, regulation of hematopoiesis, production of cytokines and cytotoxicity of neoplastic cells. Accumulating evidence suggests that the innate system is required for mounting an adequate adaptive response. NK cells, originally defined as effector cells of the innate immune system, may also play a role as regulatory cells for the adaptive immune system. This study was designed to determine the proportion of the NK cell subset of lymphocytes in umbilical cord blood of neonates born to mothers with and without pre-eclampsia.

METHODS

A cross-sectional study including neonates of mothers with (n = 48) and those without pre-eclampsia (control group) (n = 72) was conducted. Pre-eclampsia was diagnosed in the presence of hypertension and proteinuria. The control group consisted of neonates (premature and term) with no evidence of acute inflammation within the extraplacental membranes (chorioamnionitis). Umbilical cord blood was collected at the time of delivery, and assayed using monoclonal antibodies for selective cluster differentiation (CD) antigens in order to determine the proportion of NK cells as a percentage of total lymphocytes. The immunophenotypic characteristic was determined using flow cytometry, and NK cells were identified by positivity of CD16 and CD56 without CD3 (CD3-/CD56+16+). Log transformation of the percentage of NK cells was performed. Parametric statistics were used for analysis. Multiple regression analysis was utilized to examine the contribution of potentially confounding factors on the proportion of NK cells. A p value of < 0.05 was considered statistically significant.

RESULTS

Neonates born to mothers with pre-eclampsia had a significantly higher percentage of NK cells (CD3-/CD56+16+) than those in the control group (pre-eclampsia, mean +/- SD 17 +/- 9% vs. control, mean +/- SD 12 +/- 7.5%; p = 0.001). Multiple regression analysis suggested that umbilical cord blood pH of < 7.2, labor with vaginal delivery and maternal pre-eclampsia were associated with an increased percentage of NK cells in umbilical cord blood.

CONCLUSIONS

Pre-eclampsia is associated with a higher NK cell (CD3-/CD56+16+) subset of lymphocytes in umbilical cord blood than in the control group. This difference cannot be explained by fetal acidosis or the presence of labor.

Dexamethasone effects on group B streptococcal infection in newborn rats

BACKGROUND

We previously published that human neutrophil-mediated bacterial killing of group B Streptococcus (GBS) in vitro was dependent on the timing and concentration of dexamethasone exposure.

HYPOTHESIS

Dexamethasone treatment would affect neutrophil mediated killing of GBS in an animal model.

METHODS

Wistar rat pups were randomly allocated to receive placebo or dexamethasone before, early or late after GBS infection. Suckling rats were infected with 104 or 105 colony-forming units of GBS or nothing. Pups were followed for survival, quantitative bacteremia, growth and neutrophil-mediated bacterial killing. Neutrophils for bacterial killing were obtained via cardiac puncture before infection. Statistics included chi square for survival, Mann-Whitney U test for bacteremia, analysis of variance for growth and paired Student's t test for bacterial killing analyses.

RESULTS

Dexamethasone treatment before invasive GBS infection decreases quantitative bacteremia, improves survival and improves neonatal neutrophil-mediated bacterial killing in suckling rats, whereas dexamethasone treatment after infection increases bacteremia and decreases survival. Regardless of timing of dexamethasone treatment, before or after invasive GBS infection, growth was significantly impaired in all suckling rats receiving dexamethasone compared with controls.

CONCLUSION

Treatment with dexamethasone before invasive GBS infection improves survival and decreases bacteremia in suckling rats; this appears in part to be mediated by improved neonatal neutrophil-mediated bacterial killing. We speculate that this improvement in outcome may be a result of improved number or function of neutrophil cell surface receptors.

Exposure to a dysfunctional glucocorticoid receptor from early embryonic life programs the resistance to experimental autoimmune encephalomyelitis via nitric oxide-induced immunosuppression

Glucocorticoid (GC) hormones play a central role in the bidirectional communication between the neuroendocrine and the immune systems and exert, via GC receptors (GR), potent immunosuppressive and anti-inflammatory effects. In this study, we report that GR deficiency of transgenic mice expressing GR antisense RNA from early embryonic life has a dramatic impact in programming the susceptibility to experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis. GR deficiency renders mice resistant to myelin oligodendrocyte glycoprotein-induced EAE, and such mice do not develop clinical or histological signs of disease compared with EAE-susceptible wild-type mice. Resistance to EAE in GR-deficient mice is associated not with endogenous GC levels, but with a significant reduction in spleen and lymph node cell proliferation. The use of NO inhibitors in vitro indicates that NO is the candidate immunosuppressor molecule. GR-deficient mice develop 3- to 6-fold higher nitrite levels in the periphery and are resistant to NO inhibition by GCs. Specific inhibition of NO production in vivo by treatment with the inducible NO synthase inhibitor, L-N(6)-(1-iminoethyl)-lysine, suppressed circulating nitrites, increased myelin oligodendrocyte glycoprotein-specific cell proliferation, and rendered GR-deficient mice susceptible to EAE. Thus, life-long GR deficiency triggers inducible NO synthase induction and NO generation with consequent down-regulation of effector cell proliferation. These findings identify a novel link among GR, NO, and EAE susceptibility and highlight NO as critical signaling molecule in bidirectional communication between the hypothalamic-pituitary-adrenocortical axis and the immune system.

Perinatal corticosteroids and the developing lung

A significant number of infants are born prematurely each year, many of whom will develop respiratory disease and require ventilation. A substantial number of these infants will die and many of the survivors will subsequently develop chronic inflammatory lung disease. Administration of corticosteroids to women prior to a premature delivery is associated with a significant reduction in mortality and in the incidence of respiratory distress syndrome and intracranial haemorrhage in their infants once born. Postnatal administration of corticosteroids to the infant who develops chronic lung disease has been widely practised for many years. Recent meta-analyses have suggested that benefit may be limited. Treatment is also associated with a range of different side-effects but it has been assumed that the cost-benefit ratio favoured treatment. Recent evidence of permanent and highly significant long-term adverse effects has questioned the validity of this judgement.

Allergen-specific T cell reactivity in cord blood: the influence of maternal cytokine production

BACKGROUND

Successful pregnancy is dependent upon T helper (Th)2-type-dominated immunological responsiveness in gestation-associated compartments.

OBJECTIVE

In our study we observed the influence of the maternal Th2-associated cytokine pattern on the naive fetal T cell phenotype and asked if circulating Th2 cytokines of atopic mothers affects the Th1/Th2 differentiation of the fetus.

METHODS

Cord blood mononuclear cells (CBMC) and peripheral blood mononuclear cells (PBMC) of the corresponding mothers were isolated. The proliferative response of CBMC and PBMC to Betalactoglobulin (BLG) was assessed by liquid scintillation counting. The cytokines interferon (IFN)-gamma, and interleukin (IL)-5, IL-10 and IL-13 in the cell culture supernatants were measured using the ELISA technique. We then defined two subgroups based on maternal levels of specific IgE against aeroallergens: sensitized mothers (MA(+)) and their neonates (NMA(+)) (n = 18) and non-sensitized mothers (MA(-)) and their neonates (NMA(-)) (n = 29).

RESULTS

Nearly all mothers (98%) and neonates (92%) had a positive proliferation response after stimulation with BLG (mean stimulation index (10-90 percentile): neonates: 7 (2-15); mothers 14 (5-29)). In supernatants of BLG-stimulated cell cultures, sensitized mothers showed a significantly lower IFN-gamma concentration in comparison to non-sensitized mothers (MA(+) = 25; MA(-) = 123 IU/L; P < 0,05), whereas the neonates did not differ significantly (NMA(+) = 306; NMA(-) = 224 IU/L; n. s.). Nor was any difference found in the IL-13 concentration between the two groups of sensitized and non-sensitized mothers (MA(+) = 48; MA(-) = 125 pg/mL; n. s.). CBMC of neonates with a sensitized mother showed significantly higher IL-13 concentrations in response to BLG than neonates of non-sensitized mothers (NMA(+) = 1442, NMA(-) 738 pg/mL; P < 0.05). The IL-5 and IL-10 concentrations did not differ significantly within the neonatal and the maternal subgroups.

CONCLUSIONS

Our data suggests that maternal sensitization to allergens is associated with the reduced maternal production of the Th2 antagonist IFN-gamma and elevated production of the Th2 cytokine IL-13 in the offspring.

Ureaplasma urealyticum modulates endotoxin-induced cytokine release by human monocytes derived from preterm and term newborns and adults

We previously observed that Ureaplasma urealyticum respiratory tract colonization in infants with a birth weight of < or =1,250 g was associated with increases in the tracheal aspirate proinflammatory cytokines tumor necrosis factor alpha (TNF-alpha) and interleukin-8 (IL-8) relative to the counterregulatory cytokine IL-6 during the first week of life (A. M. Patterson, V. Taciak, J. Lovchik, R. E. Fox, A. B. Campbell, and R. M. Viscardi, Pediatr. Infect. Dis. J. 17:321-328, 1998). We hypothesized that U. urealyticum alters the host immune response in the presence of a coinflammatory stimulus (e.g., bacterial infection or hyperoxia) by shifting the balance of cytokine expression towards the proinflammatory cytokines. To test this hypothesis, we compared the release of TNF-alpha, IL-8, IL-6, and IL-10 in vitro by unstimulated and U. urealyticum (with or without lipopolysaccharide [LPS])-stimulated human monocytes from adult peripheral blood and from term and preterm cord blood. U. urealyticum alone and in combination with LPS induced concentration- and development-dependent changes in cytokine release. In vitro inoculation with low-inoculum U. urealyticum (10(3) color-changing units [CCU]) (i) partially blocked the LPS-stimulated IL-6 release by all cells and reduced LPS-stimulated IL-10 release by preterm cells, (ii) stimulated TNF-alpha and IL-8 release by preterm cells, and (iii) augmented LPS-stimulated TNF-alpha release in all cells. In preterm cells, high-inoculum U. urealyticum (10(6) CCU) (i) stimulated TNF-alpha and IL-8, but not IL-6 or IL-10, release and (ii) augmented LPS-stimulated TNF-alpha and IL-8 release. High-inoculum U. urealyticum (i) stimulated release of all four cytokines in term cells and IL-8 release in adult cells and (ii) augmented LPS-induced TNF-alpha, IL-10, and IL-8 release in term cells but did not significantly affect LPS-induced cytokine release in adult cells. We speculate that U. urealyticum enhances the proinflammatory response to a second infection by blocking expression of counterregulatory cytokines (IL-6 and IL-10), predisposing the preterm infant to prolonged and dysregulated inflammation, lung injury, and impaired clearance of secondary infections.

Prematurity at birth reduces the long-term risk of atopy

BACKGROUND

Antigen exposure in early life has long-lasting effects on atopic sensitization. Thus the predisposition to atopy of children born preterm can be assumed to differ from that of children born at term.

OBJECTIVE

The aim of this study was to evaluate the association between premature birth and atopy.

METHODS

At an outpatient clinic, we examined 2 groups of 10-year-old children, 72 who were born preterm (birth weight < 1500 g) and 65 who were born at term (birth weight > 2500 g). The atopy data were collected with a questionnaire, by performing skin prick testing, and by measuring the serum total IgE level, 3 allergen-specific IgE levels, the eosinophil cationic protein level, and the blood eosinophil level. The data on perinatal and neonatal events affecting the preterm children were collected from the hospital records.

RESULTS

By the age of 10 years, the children born preterm had significantly less atopy than the children born at term: 15% versus 31% of children in the 2 groups were defined as having had obvious atopy (P = .03, odds ratio 0.41, 95% CI 0.18-0.93). The mean value of total IgE level was significantly higher in the term group, 74 kU/L versus 41 kU/L (P = .02). By skin prick testing, the children born at term had positive reactions 2 to 3 times more often; 37% versus 17% of children in the groups had at least 1 positive reaction (P = .007).

CONCLUSION

Our data show that prematurity at birth is linked with a decreased long-term risk of atopic sensitization.

The effect of multidose antenatal betamethasone on maternal and infant outcomes

OBJECTIVE

This study was undertaken to determine whether prolonged betamethasone therapy is, as has been suggested, associated with adverse maternal or neonatal outcomes.

STUDY DESIGN

A secondary multivariate analysis of a randomized controlled trial was performed to determine whether duration of betamethasone therapy was associated with adverse maternal or neonatal outcomes.

RESULTS

There were 414 fetuses whose mothers were randomly assigned to trial groups. Final models included only valid cases without missing or averaged data (N = 367 to N = 412, depending on the model). Three or more sets of weekly betamethasone injections were given in 21.3% of cases and > or =4 sets were given in 12.3% of cases. Prolonged antenatal betamethasone therapy was not associated with increases in incidences of antenatal fever, chorioamnionitis, reduced birth weight, suppressed neonatal adrenal function, neonatal sepsis, or neonatal death. It was associated with larger birth weights (P <.05).

CONCLUSION

Prolonged antenatal betamethasone therapy was not associated with higher risks of antenatal maternal fever, chorioamnionitis, reduced birth weight, neonatal adrenal suppression, neonatal sepsis, and neonatal death.