Maternal smoking is associated with impaired neonatal toll-like-receptor-mediated immune responses

Interactive effects of maternal cigarette smoke, heat stress, hypoxia, and lipopolysaccharide on neonatal cardiorespiratory and cytokine responses

Maternal cigarette smoke (CS) exposure exhibits a strong epidemiological association with Sudden Infant Death Syndrome, but other environmental stressors, including infection, hyperthermia, and hypoxia, have also been postulated as important risk factors. This study examines whether maternal CS exposure causes maladaptations within homeostatic control networks by influencing the response to lipopolysaccharide, heat stress, and/or hypoxia in neonatal rats. Pregnant dams were exposed to CS or parallel sham treatments daily for the length of gestation. Offspring were studied at postnatal days 6-8 at ambient temperatures (T_a) of 33°C or 38°C. Within each group, rats were allocated to control, saline, or LPS (200 µg/kg) treatments. Cardiorespiratory patterns were examined using head-out plethysmography and ECG surface electrodes during normoxia and hypoxia (10% O₂). Serum cytokine concentrations were quantified from samples taken at the end of each experiment. Our results suggest maternal CS exposure does not alter minute ventilation (V̇e) or heart rate (HR) response to infection or high temperature, but independently increases apnea frequency. CS also primes the inflammatory system to elicit a stronger cytokine response to bacterial insult. High T_a independently depresses V̇e but augments the hypoxia-induced increase in V̇e Moreover, higher T_a increases HR during normoxia and hypoxia, and in the presence of an immune challenge, increases HR during normoxia, and reduces the increase normally associated with hypoxia. Thus, while most environmental risk factors increase the burden on the cardiorespiratory system in early life, hyperthermia and infection blunt the normal HR response to hypoxia, and gestational CS independently destabilizes breathing by increasing apneas.

Association of TLR polymorphisms with bronchopulmonary dysplasia

BACKGROUND

Bronchopulmonary dysplasia (BPD) remains a leading cause of morbidity and mortality during infancy. Evidence suggests that the Toll-like receptor (TLR) signaling pathway plays an integral role in lung inflammation and injury. This study aimed to detect single nucleotide polymorphisms (SNPs) in TLR pathway genes [TLR5 and Toll-interleukin 1 receptor domain-containing adaptor protein (TIRAP)] among preterm neonates and to determine their association with the development and severity of bronchopulmonary dysplasia.

Diabetic pregnancy activates the innate immune response through TLR5 or TLR1/2 on neonatal monocyte

Diabetes mellitus (DM) during pregnancy causes congenital malformation, macrosomia, respiratory distress syndrome, and other abnormalities in neonates, but whether maternal DM affects the neonatal innate immune system is unknown. Therefore we aimed to reveal the influence of DM in pregnancy on the toll-like receptor (TLR)-mediated innate immune response in neonates. Cord blood was collected after full-term vaginal or cesarean delivery and classified into a DM group (n=8) and non-DM (control) group (n=7). Mononuclear cells were harvested from cord blood by using density gradient centrifugation, after which anti-CD14 magnetic beads were used to isolate monocytes from the mononuclear population. After monocytes were cultured with lipopolysaccharide (TLR4 ligand), flagellin (TLR5 ligand), Pam3CSK4 (TLR1/TLR2 ligand), zymosan (TLR2/TLR6 ligand), or macrophage-activating lipopeptide (TLR2/TLR6 ligand) for 12h, the cytokine levels (interleukin [IL]-8, IL-6, IL-1β, IL-10, tumor necrosis factor alpha and IL-12) in the culture supernatants were measured. Compared with the control group, the DM group had higher concentrations of IL-8 (P=0.01) and tumor necrosis factor alpha (P=0.02) after monocyte cultures were stimulated with Pam3CSK4 and higher concentrations of IL-8 (P=0.01) after flagellin treatment. In contrast, stimulation with lipopolysaccharide, zymosan, or macrophage-activating lipopeptide did not lead to any difference in cytokine profiles between the two groups. These data indicate that maternal DM induces excessive inflammatory activation in neonates via a TLR5- or TLR1/2-mediated innate immune response.

Environmental exposure to metals, neurodevelopment, and psychosis

PURPOSE OF REVIEW

This article presents a new hypothesis about the possible relation between early life exposure to metals and psychosis. We review limitations of available research, and discuss novel approaches to overcome previous methodological barriers.

RECENT FINDINGS

Mechanistic studies suggest a possible association between excess lead, manganese, cadmium, arsenic, or copper, and zinc deficiency, and several biochemical disturbances related to psychosis, such as altered neurotransmitters levels, excitotoxicity, and inflammation. Furthermore, studies suggest that some metals (lead, manganese, cadmium excess, and zinc deficiency) are associated with schizophrenia or psychosis-related phenotype. However, previous studies had multiple methodological limitations. Importantly, metal exposure was often measured after disease development and seldom determined during critical developmental periods. Most studies fell short of depicting the exact timing of exposure and the change in exposure over time. Here, we propose several methods to overcome these methodological limitations.

SUMMARY

There is a plausible role of early life exposure to metals in the cause of psychosis. Owing to methodological limitations in exposure measurement, this has not been well characterized. Considering the wide exposure to metals and the high cost of psychosis to society, this hypothesis should be rigorously examined.

Association of toll-like receptor 2 ∆22 and risk for gastric cancer considering main effects and interactions with smoking: a matched case-control study from Mizoram, India

Toll-like receptors (TLRs) are evolutionary conserved cell surface receptors of the innate immune system. Smoking has significant immunological effects which are mediated via TLRs on various receptor-mediated innate response pathways. Polymorphisms of TLR genes are associated with susceptibility toward various malignancies. The present study was undertaken to examine the association between TLR2 ∆22 and gastric cancer. In this study, we also investigated the interaction between TLR2 ∆22 and smoking. A total of 133 histologically confirmed gastric cancer cases and 266 age-sex-matched controls were selected for this study. TLR2 ∆22 genotypes were determined by allele-specific polymerase chain reaction (PCR). Binary conditional logistic regression analysis was used to find the association of TLR2 ∆22 with risk of gastric cancer. Logistic regression using hierarchically well-formulated models was used for interaction analysis between smoking and TLR2 ∆22. Persons having TLR2 ∆22 heterozygous genotype had two times increased risk of gastric cancer in multivariate logistic regression model. The interaction analysis using hierarchical logistic regression models between smoking and TLR2 ∆22 by calculating separate X (2) for interaction model and only main effect model, the difference of X (2) 57.68-47.70 = 9.98 and degrees of freedom (df) 5-3 = 2, revealed significant (α = 0.05, df = 2) omnibus interaction. Our present study revealed TLR2 ∆22 to be significantly and independently associated with gastric cancer risk in Mizoram, and there is also evidence of significant interaction between smoking and TLR2 ∆22 with risk of gastric cancer.

Early-life Exposure to Widespread Environmental Toxicants and Health Risk: A Focus on the Immune and Respiratory Systems

Evidence has accumulated that exposure to widespread environmental toxicants, such as heavy metals, persistent organic pollutants, and tobacco smoke adversely affect fetal development and organ maturation, even after birth. The developing immune and respiratory systems are more sensitive to environmental toxicants due to their long-term physical development, starting from the early embryonic stage and persisting into early postnatal life, which requires complex signaling pathways that control proliferation and differentiation of highly heterogeneous cell types. In this review, we summarize the effect of early-life exposure to several widespread environmental toxicants on immune and lung development before and after birth, including the effects on immune cell counts, baseline characteristics of cell-mediated and humoral immunity, and alteration of lung structure and function in offspring. We also review evidence supporting the association between early-life exposure to environmental toxicants and risk for immune-related diseases and lung dysfunction in offspring in later life.

In Utero Cigarette Smoke Affects Allergic Airway Disease But Does Not Alter the Lung Methylome

Prenatal and postnatal cigarette smoke exposure enhances the risk of developing asthma. Despite this as well as other smoking related risks, 11% of women still smoke during pregnancy. We hypothesized that cigarette smoke exposure during prenatal development generates long lasting differential methylation altering transcriptional activity that correlates with disease. In a house dust mite (HDM) model of allergic airway disease, we measured airway hyperresponsiveness (AHR) and airway inflammation between mice exposed prenatally to cigarette smoke (CS) or filtered air (FA). DNA methylation and gene expression were then measured in lung tissue. We demonstrate that HDM-treated CS mice develop a more severe allergic airway disease compared to HDM-treated FA mice including increased AHR and airway inflammation. While DNA methylation changes between the two HDM-treated groups failed to reach genome-wide significance, 99 DMRs had an uncorrected p-value < 0.001. 6 of these 99 DMRs were selected for validation, based on the immune function of adjacent genes, and only 2 of the 6 DMRs confirmed the bisulfite sequencing data. Additionally, genes near these 6 DMRs (Lif, Il27ra, Tle4, Ptk7, Nfatc2, and Runx3) are differentially expressed between HDM-treated CS mice and HDM-treated FA mice. Our findings confirm that prenatal exposure to cigarette smoke is sufficient to modify allergic airway disease; however, it is unlikely that specific methylation changes account for the exposure-response relationship. These findings highlight the important role in utero cigarette smoke exposure plays in the development of allergic airway disease.

Risk factors and early origins of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease is mainly a smoking-related disorder and affects millions of people worldwide, with a large effect on individual patients and society as a whole. Although the disease becomes clinically apparent around the age of 40-50 years, its origins can begin very early in life. Different risk factors in very early life--ie, in utero and during early childhood--drive the development of clinically apparent chronic obstructive pulmonary disease in later life. In discussions of which risk factors drive chronic obstructive pulmonary disease, it is important to realise that the disease is very heterogeneous and at present is largely diagnosed by lung function only. In this Review, we will discuss the evidence for risk factors for the various phenotypes of chronic obstructive pulmonary disease during different stages of life.

Toward primary prevention of asthma. Reviewing the evidence for early-life respiratory viral infections as modifiable risk factors to prevent childhood asthma

A first step in primary disease prevention is identifying common, modifiable risk factors that contribute to a significant proportion of disease development. Infant respiratory viral infection and childhood asthma are the most common acute and chronic diseases of childhood, respectively. Common clinical features and links between these diseases have long been recognized, with early-life respiratory syncytial virus (RSV) and rhinovirus (RV) lower respiratory tract infections (LRTIs) being strongly associated with increased asthma risk. However, there has long been debate over the role of these respiratory viruses in asthma inception. In this article, we systematically review the evidence linking early-life RSV and RV LRTIs with asthma inception and whether they could therefore be targets for primary prevention efforts.

In vivo Cigarette Smoke Exposure Decreases CCL20, SLPI, and BD-1 Secretion by Human Primary Nasal Epithelial Cells

Smokers and individuals exposed to second-hand cigarette smoke have a higher risk of developing chronic sinus and bronchial infections. This suggests that cigarette smoke (CS) has adverse effects on immune defenses against pathogens. Epithelial cells are important in airway innate immunity and are the first line of defense against infection. Airway epithelial cells not only form a physical barrier but also respond to the presence of microbes by secreting antimicrobials, cytokines, and chemokines. These molecules can lyse infectious microorganisms and/or provide signals critical to the initiation of adaptive immune responses. We examined the effects of CS on antimicrobial secretions of primary human nasal epithelial cells (PHNECs). Compared to non-CS-exposed individuals, PHNEC from in vivo CS-exposed individuals secreted less chemokine ligand (C-C motif) 20 (CCL20), Beta-defensin 1 (BD-1), and SLPI apically, less BD-1 and SLPI basolaterally, and more CCL20 basolaterally. Cigarette smoke extract (CSE) exposure in vitro decreased the apical secretion of CCL20 and beta-defensin 1 by PHNEC from non-CS-exposed individuals. Exposing PHNEC from non-CS exposed to CSE also significantly decreased the levels of many mRNA transcripts that are involved in immune signaling. Our results show that in vivo or in vitro exposure to CS alters the secretion of key antimicrobial peptides from PHNEC, but that in vivo CS exposure is a much more important modifier of antimicrobial peptide secretion. Based on the gene expression data, it appears that CSE disrupts multiple immune signaling pathways in PHNEC. Our results provide mechanistic insight into how CS exposure alters the innate immune response and increases an individual's susceptibility to pathogen infection.

The role of environmental factors in modulating immune responses in early life

The concept of immunological memory stipulates that past exposures shape present immune function. These exposures include not only specific antigens impacting adaptive immune memory but also conserved pathogen or danger associated molecular patterns that mold innate immune responses for prolonged periods of time. It should thus not come as a surprise that there is a vast range of external or environmental factors that impact immunity. The importance of environmental factors modulating immunity is most readily recognized in early life, a period of rapidly changing environments. We here summarize available data on the role of environment shaping immune development and from it derive an overarching hypothesis relating the underlying molecular mechanisms and evolutionary principles involved.

Maturation of innate responses to mycobacteria over the first nine months of life

Newborns and young infants are particularly susceptible to infections, including Mycobacterium tuberculosis. Further, immunogenicity of vaccines against tuberculosis and other infectious diseases appears suboptimal early in life compared with later in life. We hypothesized that developmental changes in innate immunity would underlie these observations. To determine the evolution of innate responses to mycobacteria early in life, whole blood or PBMC from newborns, as well as 10- and 36-wk-old infants, was incubated with viable Mycobacterium bovis bacillus Calmette-Guérin or TLR ligands. Innate cell expression of cytokines and maturation markers was assessed, as well as activation of the proinflammatory NF-κB- and MAPK-signaling pathways. Bacillus Calmette-Guérin-induced production of the proinflammatory cytokines TNF-α, IL-6, and IL-12p40 increased from the newborn period to 9 mo of age in monocytes but not in myeloid dendritic cells. No changes in production of anti-inflammatory IL-10 were observed. CD40 expression increased with age in both cell populations. Older infants displayed substantial activation of all three signal transduction molecules: degradation of NF-κB inhibitor IκBα and phosphorylation of MAPK Erk and p38 upon TLR1/2 triggering, compared with predominant activation of only one of any of these molecules in newborns. Maturation of innate proinflammatory responses during the first 9 mo of life may underlie more effective control of mycobacteria and other pathogens observed later in infancy and age-related differential induction of Th1 responses by vaccination.

Persistent effects of maternal smoking during pregnancy on lung function and asthma in adolescents

RATIONALE

The extent to which maternal smoking in pregnancy (MSP) has persisting effects on respiratory health remains uncertain and the mechanisms involved are not fully understood. Alterations in immune function have been proposed as a mechanism contributing to respiratory disease.

OBJECTIVES

To determine whether MSP increases risk of respiratory disorders in adolescence and, if so, whether this occurs by decreased lung function, altered immune function, and/or enhanced atopy.

METHODS

Data on spirometry, bronchial responsiveness, respiratory symptoms, total and allergen-specific IgE and IgG4, immune function, and inflammatory markers were obtained from 1,129 participants in the 14-year follow-up of the Western Australian Pregnancy (Raine) Cohort and related to MSP using regression analyses.

MEASUREMENTS AND MAIN RESULTS

MSP was reported for 21.0% (237 of 1,129) of participants, with 92 (8.1%) reporting current smoking. MSP was associated with some altered immune measures at age 14. MSP was strongly related to reduced lung function in current nonsmokers (forced expiratory flow midexpiratory phase [FEF25-75%], P = 0.016; FEV1/FVC, P = 0.009) and increased risk for current asthma (odds ratio [OR], 1.84; 95% confidence interval [CI], 1.16-2.92; P = 0.01), current wheeze (OR, 1.77; 95% CI, 1.14-2.75; P = 0.011), and exercise-induced wheeze (OR, 2.29; 95% CI, 1.37-3.85; P = 0.002), but not for bronchial hyperresponsiveness or atopy. Adjustment for immune measures and/or lung function in multivariate models did not greatly alter these associations and the increased risks for asthma and wheeze were not modified by sex, atopy, or maternal history of asthma or atopy.

CONCLUSIONS

MSP increases risk of asthma and wheezing in adolescence; mechanisms go beyond reducing lung function and exclude altering immune function or enhancing atopy.

Disease prevention in the age of convergence - the need for a wider, long ranging and collaborative vision

It is time to bring our imagination, creativity and passion to the fore in solving the global challenges of our age. Our global health crisis and the pandemic of noncommunicable diseases (NCDs) is clearly rooted in complex modern societal and environmental changes, many of which have effects on developing immune and metabolic responses. It is intimately related to wider environmental challenges. And it is unsurprising that many NCDs share similar risk factors and that many are associated with a rising predisposition for inflammation. Allergy is one of the earliest signs of environmental impact on these biological pathways, and may also offer an early barometer to assess the effects of early interventions. There is dawning awareness of how changing microbial diversity, nutritional patterns, sedentary indoor behaviours and modern pollutants adversely affect early metabolic and immune development, but still much to understand the complexity of these interactions. Even when we do harness the science and technology, these will not provide solutions unless we also address the wider social, cultural and economic determinants of health - addressing the interconnections between human health and the health of our environment. Now more than ever, we need a wider vision and a greater sense of collective responsibility. We need long-range approaches that aim for life long benefits of a 'healthier start to life', and stronger cross-sectoral collaborations to prevent disease. We need to give both our hearts and our minds to solving these global issues.

Developmental Immunotoxicity, Perinatal Programming, and Noncommunicable Diseases: Focus on Human Studies

Developmental immunotoxicity (DIT) is a term given to encompass the environmentally induced disruption of normal immune development resulting in adverse outcomes. A myriad of chemical, physical, and psychological factors can all contribute to DIT. As a core component of the developmental origins of adult disease, DIT is interlinked with three important concepts surrounding health risks across a lifetime: (1) the Barker Hypothesis, which connects prenatal development to later-life diseases, (2) the hygiene hypothesis, which connects newborns and infants to risk of later-life diseases and, (3) fetal programming and epigenetic alterations, which may exert effects both in later life and across future generations. This review of DIT considers: (1) the history and context of DIT research, (2) the fundamental features of DIT, (3) the emerging role of DIT in risk of noncommunicable diseases (NCDs) and (4) the range of risk factors that have been investigated through human research. The emphasis on the human DIT-related literature is significant since most prior reviews of DIT have largely focused on animal research and considerations of specific categories of risk factors (e.g., heavy metals). Risk factors considered in this review include air pollution, aluminum, antibiotics, arsenic, bisphenol A, ethanol, lead (Pb), maternal smoking and environmental tobacco smoke, paracetamol (acetaminophen), pesticides, polychlorinated biphenyls, and polyfluorinated compounds.

Prenatal and childhood infections: implications for the development and treatment of childhood asthma

Bacterial and viral infections occur early and recurrently in life and thereby impose a substantial disease burden. Besides causing clinical symptoms, a potential role of infection in the development of the asthma syndrome later in life has also been suggested. However, whether bacterial and viral infections unmask host factors in children at risk of asthma or whether they directly cause asthma remains unclear; both viewpoints could be justified, but the underlying mechanisms are complex and poorly understood. Recently, the role of the bacterial microbiome has been emphasised. But data are still sparse and future studies are needed for definitive conclusions to be made. In this Review, we discuss present knowledge of viruses and bacteria that infect and colonise the respiratory tract and mucosal surfaces, including their timepoint of action, host factors related to infection, and their effect on childhood asthma. Childhood asthma could be the result of a combination of altered host susceptibility and infectious agents.

Tobacco smoke increases the risk of otitis media among Greenlandic Inuit children while exposure to organochlorines remain insignificant

BACKGROUND

Prenatal exposure to environmental levels of organochlorines (OCs) has been demonstrated to have immunotoxic effects in humans. We investigated the relationship between prenatal exposure to OCs and the occurrence of otitis media (OM) among Inuit children in Greenland.

METHODS

We estimated the concentration of 14 PCB congeners and 11 pesticides in maternal and cord blood samples and in breast milk in a population-based cohort of 400 mother-child pairs. At follow-up, we examined the children's ears and used their medical records to assess the OM occurrence and severity. Multivariate regression analyses were used with adjustments for passive smoking, crowding, dietary habits, parent's educational level, breast feeding and the use of child-care.

RESULTS

The children were 4-10 years of age at follow-up and 223 (85%) participated. We found no association between prenatal OC exposure and the development of OM. Factors associated with the child's hazard of OM during the first 4 years of life were: mother's history of OM (HR 1.70, 95% CI 1.11-2.59, p=0.01); mother's smoking habits: current (HR 2.47, 95% CI 1.45-4.21, p<0.01) and previous (HR 2.00, 95% CI 1.19-3.36, p<0.01); number of smokers in the home (HR 1.17, 95% CI 1.05-1.31, p<0.01). After adjustment mothers' smoking habits remained significant.

CONCLUSION

We found no relationship between high levels of prenatal exposure of OCs and occurrence of OM. Passive smoking was found as the strongest environmental risk factor for the development of OM. Interventions to reduce passive smoke in children's environment are needed.

Early-life environmental determinants of allergic diseases and the wider pandemic of inflammatory noncommunicable diseases

The unparalleled burden of a diverse range of chronic noncommunicable diseases (NCDs) is a major global challenge in the 21st century. Chronic low-grade inflammation is a common feature of virtually all NCDs, indicating a central role of the immune system. Furthermore, as the most common and earliest-onset NCD, the epidemic of allergic diseases points to specific vulnerability of the developing immune system to modern environmental change. Indeed, many environmental risk factors implicated in the rise of other NCDs have been shown to mediate their effects through immune pathways. The innate immune system provides a clear example of this convergence, with evidence that physical activity, nutrition, pollutants, and the microbiome all influence systemic inflammation through Toll-like receptor pathways (notably Toll-like receptor 4), with downstream effects on the risk of insulin resistance, obesity, cardiovascular risk, immune diseases, and even mood and behavior. Common risk factors will likely mean common solutions, and interdisciplinary strategies to promote immune health should be an integral part of NCD prevention, with a greater focus early in the life course before disease processes are established. In this context allergic disease provides a very important early target to assess the effectiveness of environmental strategies to reduce immune dysregulation.

Recurrent lower respiratory tract infections in children: a practical approach to diagnosis

Many children are affected by recurrent lower respiratory tract infections (LRTIs), but the majority of them do not suffer from serious lung or extrapulmonary disease. The challenge for clinicians is to distinguish the recurrent RTIs with self-limiting or minor problems from those with underlying disease. The aim of this review is to describe a practical approach to children with recurrent LRTIs that limits unnecessary, expensive and time-consuming investigations. The children can be divided into three groups on the basis of their personal and family history and clinical findings: 1) otherwise healthy children who do not need further investigations; 2) those with risk factors for respiratory infections for whom a wait-and-see approach can be recommended; and 3) those in whom further investigations are mandatory. However, regardless of the origin of the recurrent LRTIs, it is important to remember that prevention by means of vaccines against respiratory pathogens (i.e. type b Haemophilus influenzae, pertussis, pneumococcal and influenza vaccines) can play a key role.

Allergy Takes Its Toll: The Role of Toll-like Receptors in Allergy Pathogenesis

Reduced early microbial exposure in early life has become a leading candidate to explain the escalating rate of allergic disease and has generated intense interest in the interaction between the developing immune system and the microbial environment. Infants depend on "signal" from the microbial environment to mature both T-helper cell type 1 and regulatory immune function. These signals, mediated through microbial pattern-recognition receptors, namely toll-like receptors (TLRs), seem essential to achieving the immunologic balance required for (1) pathogen protection and (2) normal immune tolerance. Despite this, the normal development of TLR function has never been documented. There is preliminary evidence that TLR function is under the influence of both genetic factors (genetic polymorphisms) and early environmental exposures including microbial exposure and breast feeding, and maternal smoking. This review explores the evidence that allergy is associated with developmental variations in TLR-mediated immune function and how this may be relevant for disease prevention.

Elevated IL-17A levels in early stages of bladder cancer regardless of smoking status

Aim: The interrelation between nicotine and IL-17A in bladder cancer (BC) patients was investigated. Methods: IL-17A in the sera of 121 BC patients who smoked nicotine, 80 nonsmoker BC patients, 29 and 30 age- and sex-matched healthy smokers and nonsmokers were also measured. Results: IL-17A was elevated in smoker and nonsmoker BC patients compared with smoker and nonsmoker controls (p = 0.004 and p = 0.004, respectively). The level of IL-17A in BC patients who smoked both water pipes and cigarettes were the highest (4.35±8.57 pg/ml), followed by BC water pipe users only (1.33±3.122 pg/ml) and cigarette smokers only (0.79±2.26 pg/ml, p = 0.001). IL-17A was elevated in lower stages (I and II) compared with higher stages (III and IV) of the disease (p = 0.013). Conclusion: IL-17A levels are elevated in some BC patients. IL-17A is an important factor in the inflammatory process during tumor progression, either as a defense mechanism or as a tumor-promoting factor.

Meconium microbiota types dominated by lactic acid or enteric bacteria are differentially associated with maternal eczema and respiratory problems in infants

BACKGROUND

Culture-dependent methods have shown that meconium, the newborn's first intestinal discharge, is not sterile, but the diversity of bacteria present in this material needs to be further characterized by means of more sensitive molecular techniques.

OBJECTIVE

Our aims were to characterize molecularly the meconium microbiota in term infants, to assess whether it contributes to the future microbiota of the infants' gastrointestinal tract, and to evaluate how it relates to lifestyle variables and atopy-related conditions.

METHODS

We applied high-throughput pyrosequencing of the 16S rRNA gene to study the meconium microbiota in twenty term newborns from a Spanish birth cohort. For comparison, we characterized the microbiota in fecal samples from seven pregnant women days before delivery and in two series of infant samples spanning the first seven months of life. We also compared our data with vaginal and skin microbiota characterized in independent studies. Different types of meconium microbiota were defined based on taxonomic composition and abundance and their associations with different factors were statistically evaluated.

RESULTS

The meconium microbiota differs from those in adult feces, vagina and skin, but resembles that of fecal samples from young infants. Meconium samples clustered into two types with different bacterial diversity, richness and composition. One of the types was less diverse, dominated by enteric bacteria and associated with a history of atopic eczema in the mother (P = 0.038), whereas the second type was dominated by lactic acid bacteria and associated with respiratory problems in the infant (P = 0.040).

CONCLUSIONS & CLINICAL RELEVANCE

Our findings suggest that the meconium microbiota has an intrauterine origin and participates in gut colonization. Although based on a small population sample, our association analyses also suggest that the type of bacteria detected in meconium is influenced by maternal factors and may have consequences for childhood health.

Association of maternal smoking during pregnancy with infant hospitalization and mortality due to infectious diseases

BACKGROUND

Maternal smoking is associated with infant respiratory infections and with increased risk of low birth weight infants and preterm birth. This study assesses the association of maternal smoking during pregnancy with both respiratory and nonrespiratory infectious disease (ID) morbidity and mortality in infants.

METHODS

We conducted 2 retrospective case-control analyses of infants born in Washington State from 1987 to 2004 using linked birth certificate, death certificate and hospital discharge records. One assessed morbidity--infants hospitalized due to IDs within 1 year of birth (47,404 cases/48,233 controls). The second assessed mortality--infants who died within 1 year due to IDs (627 cases/2730 controls).

RESULTS

Maternal smoking was associated with both hospitalization (adjusted odds ratio [AOR] = 1.52; 95% confidence interval [CI]: 1.46, 1.58) and mortality (AOR = 1.51; 95% CI: 1.17, 1.96) due to any ID. In subgroup analyses, maternal smoking was associated with hospitalization due to a broad range of IDs including both respiratory (AOR = 1.69; 95% CI: 1.63, 1.76) and nonrespiratory IDs (AOR = 1.27; 95% CI: 1.20, 1.34). Further stratification by birth weight and gestational age did not appreciably change these estimates. In contrast, there was no association of maternal smoking with ID infant mortality when only low birth weight infants were considered.

CONCLUSIONS

Maternal smoking was associated with a broad range of both respiratory and nonrespiratory ID outcomes. Despite attenuation of the mortality association among low birth weight infants, ID hospitalization was found to be independent of both birth weight and gestational age. These findings suggest that full-term infants of normal weight whose mothers smoked may suffer an increased risk of serious ID morbidity and mortality.

Cotinine inhibits the pro-inflammatory response initiated by multiple cell surface Toll-like receptors in monocytic THP cells

Background

The primary, stable metabolite of nicotine [(S)-3-(1-methyl-2-pyrrolidinyl) pyridine] in humans is cotinine [(S)-1-methyl-5-(3-pyridinyl)-2-pyrrolidinone]. We have previously shown that cotinine exposure induces convergence and amplification of the GSK3β-dependent PI3 kinase and cholinergic anti-inflammatory systems. The consequence is reduced pro-inflammatory cytokine secretion by human monocytes responding to bacteria or LPS, a TLR4 agonist.

Findings

Here we show that cotinine-induced inflammatory suppression may not be restricted to individual Toll-like receptors (TLRs). Indeed, in monocytic cells, cotinine suppresses the cytokine production that is normally resultant upon agonist-specific engagement of all of the major surface exposed TLRs (TLR 2/1; 2/6; 4 and 5), although the degree of suppression varies by TLR.

Conclusions

These results provide further mechanistic insight into the increased susceptibility to multiple bacterial infections known to occur in smokers. They also establish THP-1 cells as a potentially suitable model with which to study the influence of tobacco components and metabolites on TLR-initiated inflammatory events.

Response to infections in patients with asthma and atopic disease: an epiphenomenon or reflection of host susceptibility?

Associations between respiratory tract infections and asthma inception and exacerbations are well established. Infant respiratory syncytial virus and rhinovirus infections are known to be associated with an increased risk of asthma development, and among children with prevalent asthma, 85% of asthma exacerbations are associated with viral infections. However, the exact nature of this relationship remains unclear. Is the increase in severity of infections an epiphenomenon, meaning respiratory tract infections just appear to be more severe in patients with underlying respiratory disease, or instead a reflection of altered host susceptibility among persons with asthma and atopic disease? The main focus of this review is to summarize the available levels of evidence supporting or refuting the notion that patients with asthma or atopic disease have an altered susceptibility to selected pathogens, as well as discussing the biological mechanism or mechanisms that might explain such associations. Finally, we will outline areas in need of further research because understanding the relationships between infections and asthma has important implications for asthma prevention and treatment, including potential new pathways that might target the host immune response to select pathogens.

Early childhood poverty, immune-mediated disease processes, and adult productivity

This study seeks to understand whether poverty very early in life is associated with early-onset adult conditions related to immune-mediated chronic diseases. It also tests the role that these immune-mediated chronic diseases may play in accounting for the associations between early poverty and adult productivity. Data (n = 1,070) come from the US Panel Study of Income Dynamics and include economic conditions in utero and throughout childhood and adolescence coupled with adult (age 30-41 y) self-reports of health and economic productivity. Results show that low income, particularly in very early childhood (between the prenatal and second year of life), is associated with increases in early-adult hypertension, arthritis, and limitations on activities of daily living. Moreover, these relationships and particularly arthritis partially account for the associations between early childhood poverty and adult productivity as measured by adult work hours and earnings. The results suggest that the associations between early childhood poverty and these adult disease states may be immune-mediated.

Air pollution during pregnancy and neonatal outcome: a review

There is increasing evidence of the adverse impact of prenatal exposure to air pollution. This is of particular interest, as exposure during pregnancy--a crucial time span of important biological development--may have long-term implications. The aims of this review are to show current epidemiological evidence of known effects of prenatal exposure to air pollution and present possible mechanisms behind this process. Harmful effects of exposure to air pollution during pregnancy have been shown for different birth outcomes: higher infant mortality, lower birth weight, impaired lung development, increased later respiratory morbidity, and early alterations in immune development. Although results on lower birth weight are somewhat controversial, evidence for higher infant mortality is consistent in studies published worldwide. Possible mechanisms include direct toxicity of particles due to particle translocation across tissue barriers or particle penetration across cellular membranes. The induction of specific processes or interaction with immune cells in either the pregnant mother or the fetus may be possible consequences. Indirect effects could be oxidative stress and inflammation with consequent hemodynamic alterations resulting in decreased placental blood flow and reduced transfer of nutrients to the fetus. The early developmental phase of pregnancy is thought to be very important in determining long-term growth and overall health. So-called "tracking" of somatic growth and lung function is believed to have a huge impact on long-term morbidity, especially from a public health perspective. This is particularly important in areas with high levels of outdoor pollution, where it is practically impossible for an individual to avoid exposure. Especially in these areas, good evidence for the association between prenatal exposure to air pollution and infant mortality exists, clearly indicating the need for more stringent measures to reduce exposure to air pollution.

Maternal smoking during pregnancy, prematurity and recurrent wheezing in early childhood

BACKGROUND

Prenatal maternal smoking and prematurity independently affect wheezing and asthma in childhood.

OBJECTIVE

We sought to evaluate the interactive effects of maternal smoking and prematurity upon the development of early childhood wheezing.

METHODS

We evaluated 1,448 children with smoke exposure data from a prospective urban birth cohort in Boston. Maternal antenatal and postnatal exposure was determined from standardized questionnaires. Gestational age was assessed by the first day of the last menstrual period and early prenatal ultrasound (preterm < 37 weeks gestation). Wheezing episodes were determined from medical record extraction of well and ill/unscheduled visits. The primary outcome was recurrent wheezing, defined as ≥ 4 episodes of physician documented wheezing. Logistic regression models and zero inflated negative binomial regression (for number of episodes of wheeze) assessed the independent and joint association of prematurity and maternal antenatal smoking on recurrent wheeze, controlling for relevant covariates.

RESULTS

In the cohort, 90 (6%) children had recurrent wheezing, 147 (10%) were exposed to in utero maternal smoke and 419 (29%) were premature. Prematurity (odds ratio [OR] 2.0; 95% confidence interval [CI], 1.3-3.1) was associated with an increased risk of recurrent wheezing, but in utero maternal smoking was not (OR 1.1, 95% CI 0.5-2.4). Jointly, maternal smoke exposure and prematurity caused an increased risk of recurrent wheezing (OR 3.8, 95% CI 1.8-8.0). There was an interaction between prematurity and maternal smoking upon episodes of wheezing (P = 0.049).

CONCLUSIONS

We demonstrated an interaction between maternal smoking during pregnancy and prematurity on childhood wheezing in this urban, multiethnic birth cohort.

Fatty acids as biocompounds: their role in human metabolism, health and disease: a review. part 2: fatty acid physiological roles and applications in human health and disease

BACKGROUND

This is the second of two review parts aiming at describing the major physiological roles of fatty acids, as well as their applications in specific conditions related to human health.

RESULTS

The review included the current literature published in Pubmed up to March 2011. In humans, fatty acids are a principle energy substrate and structural components of cell membranes (phospholipids) and second messengers. Fatty acids are also ligands of nuclear receptors affecting gene expression. Longer-chain (LC) polyunsaturated fatty acids (PUFA), including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid are precursors of lipid mediators such as eicosanoids (prostaglandins, leukotrienes, thromboxanes), resolvins and neuroprotectins. Lipid mediators produced by EPA and DHA (LC n-3 PUFA; mainly found in oily fish) are considered as inflammation-resolving, and thus, fish oil has been characterised as antiinflammatory. Recommendations for EPA plus DHA intake from oily fish vary between 250-450 mg/day. Dietary reference values for fat vary between nutrition bodies, but mainly agree on a low total and saturated fat intake. The existing literature supports the protective effects of LC n-3 PUFA (as opposed to n-6 PUFA and saturated fat) in maternal and offspring health, cardiovascular health, insulin sensitivity, the metabolic syndrome, cancer, critically ill patients, and immune system disorders.

CONCLUSION

Fatty acids are involved in multiple pathways and play a major role in health. Further investigation and a nutrigenomics approach to the effects of these biocompounds on health and disease development are imperative and highlight the importance of environmental modifications on disease outcome.

Cord blood Tregs with stable FOXP3 expression are influenced by prenatal environment and associated with atopic dermatitis at the age of one year

BACKGROUND

Regulatory T cells (Tregs) with stable FOXP3 expression are characterized by a specific demethylated region in the FOXP3 gene (Treg-specific demethylated region, TSDR). The aim of this study was to analyse the influence of prenatal factors on cord blood Treg numbers, as detected by changes in the TSDR demethylation, and the subsequent risk for allergic diseases.

METHODS

Analyses were performed within the LINA study in blood samples from pregnant women (34th gestational week) and in cord blood (n = 346 mother-child pairs). Treg numbers were detected via DNA demethylation in the FOXP3 TSDR. At age 1, total and specific IgE was measured in children's blood. In addition, maternal cytokine production (Th1/Th2/Th17) was analysed. Exposure and disease outcomes were assessed by questionnaires.

RESULTS

Boys had lower Treg numbers compared with girls (P < 0.001). Parental atopy history, particularly maternal hay fever and paternal asthma were related to lower Treg numbers in cord blood (adj. MR = 0.81, 95% CI = 0.68-0.97; adj. MR = 0.60, 95% CI = 0.45-0.81). Maternal cytokines (IL-13, IL-17E and IFN-γ) and maternal smoking/exposure to tobacco smoke during pregnancy were also associated with decreased cord blood Treg numbers (adj. MR = 0.89, 95% CI = 0.97-1.00). Children with lower Treg numbers at birth had a higher risk to develop atopic dermatitis (adj. OR = 1.55, 95% CI = 1.00-2.41) and sensitization to food allergens (adj. OR = 1.55, 95% CI = 1.06-2.25) during the first year of life.

CONCLUSIONS

These results indicate that both genetic and environmental factors presumably influence the development of foetal Tregs. Low cord blood Treg numbers may predict early atopic dermatitis.

Breastfeeding modulates neonatal innate immune responses: a prospective birth cohort study

BACKGROUND

Neonatal Toll-like receptor (TLR) responses are biased toward Th2-polarizing responses at birth and rapidly mature toward more balanced responses during the first month of life. Postnatal TLR maturation may be guided by environmental exposure.

AIMS

To determine the environmental determinants of neonatal TLR function.

MATERIALS AND METHODS

A prospective birth cohort study was performed in 291 healthy term neonates. Mode of delivery, breastfeeding, birth month, siblings, pets and parental smoking were analyzed in relation to neonatal innate immune parameters at the age of 1 month. Whole blood concentrations of innate immune cells were measured by flow cytometry. In vitro TLR-mediated cytokine production was determined by ELISA.

RESULTS

Breastfeeding was the major determinant of neonatal innate immunity, associated with 5 (31%) of neonatal innate immune parameters, of which the association with TLR7-mediated IL-10 production was most significant (76 pg/ml in breastfed neonates vs. 293 pg/ml in formula-fed neonates, p = 0.001). Of innate immune variables, TLR3-mediated IL-12p70 production was highly associated with environmental exposures (pets, breastfeeding and mode of delivery), whereas TLR9-mediated cytokine responses were not associated with any environmental factor.

CONCLUSION

Neonatal innate immune responses are differentially modulated by environmental exposure in the first month of life. The protective effect of breastfeeding against subsequent infections and atopy might be explained by its innate immune modulatory effects in the first month of life.

Prenatal programming of the innate immune response following in utero exposure to inflammation: a sexually dimorphic process?

Maternal infection and inflammation are common events during pregnancy. This article documents evidence that suggests such inflammation compromises the development of the fetal innate immune response, in support of an in utero origins hypothesis of neonatal and childhood inflammatory disease. The potential for this response to exhibit sex specificity is also explored, based on evidence of sexually dimorphic placental responses to maternal inflammation.

The impact of perinatal immune development on mucosal homeostasis and chronic inflammation

The mucosal surfaces of the gut and airways have important barrier functions and regulate the induction of immunological tolerance. The rapidly increasing incidence of chronic inflammatory disorders of these surfaces, such as inflammatory bowel disease and asthma, indicates that the immune functions of these mucosae are becoming disrupted in humans. Recent data indicate that events in prenatal and neonatal life orchestrate mucosal homeostasis. Several environmental factors promote the perinatal programming of the immune system, including colonization of the gut and airways by commensal microorganisms. These complex microbial-host interactions operate in a delicate temporal and spatial manner and have an important role in the induction of homeostatic mechanisms.

Exposure to moderate air pollution during late pregnancy and cord blood cytokine secretion in healthy neonates

Background/Objectives

Ambient air pollution can alter cytokine concentrations as shown in vitro and following short-term exposure to high air pollution levels in vivo. Exposure to pollution during late pregnancy has been shown to affect fetal lymphocytic immunophenotypes. However, effects of prenatal exposure to moderate levels of air pollutants on cytokine regulation in cord blood of healthy infants are unknown.

Methods

In a birth cohort of 265 healthy term-born neonates, we assessed maternal exposure to particles with an aerodynamic diameter of 10 µm or less (PM₁₀), as well as to indoor air pollution during the last trimester, specifically the last 21, 14, 7, 3 and 1 days of pregnancy. As a proxy for traffic-related air pollution, we determined the distance of mothers' homes to major roads. We measured cytokine and chemokine levels (MCP-1, IL-6, IL-10, IL-1ß, TNF-α and GM-CSF) in cord blood serum using LUMINEX technology. Their association with pollution levels was assessed using regression analysis, adjusted for possible confounders.

Results

Mean (95%-CI) PM₁₀ exposure for the last 7 days of pregnancy was 18.3 (10.3–38.4 µg/m³). PM₁₀ exposure during the last 3 days of pregnancy was significantly associated with reduced IL-10 and during the last 3 months of pregnancy with increased IL-1ß levels in cord blood after adjustment for relevant confounders. Maternal smoking was associated with reduced IL-6 levels. For the other cytokines no association was found.

Conclusions

Our results suggest that even naturally occurring prenatal exposure to moderate amounts of indoor and outdoor air pollution may lead to changes in cord blood cytokine levels in a population based cohort.

Modulation of asthma and allergy by addressing toll-like receptor 2

Toll-like receptors play an important role in innate and adaptive immunity and in balancing immune responses with tolerance. TLR2 is related to protection against allergies and allergic asthma by sensing pathogen associated patterns as lipoproteins and lipopeptides. A constant Th1 triggering is thought to prevent Th2 related disorders.

TLR2 is expressed on a variety of cells, both structural as well as immune cells. Importantly, TLR2 is also expressed on dendritic cells, which are thought to be one of the key players of initiating and maintaining immune responses. Therefore, TLR2 on dendritic cells is a good target for modulating immunity either to Th1 or Th2 responses, or induction of tolerance.

TLR2 agonists show high immunomodulatory and adjuvantic capacity. This makes TLR2 agonisation a promising approach for pharmaceutical intervention of allergic disorders.

The role of microbes in developmental immunologic programming

The role of microorganisms in the gastrointestinal tract has undergone significant modification in the past few decades with new observations from clinical, epidemiologic, and basic science research. We now know that the perception of these gut microbes as pathogens or even as commensals is somewhat outdated. It is becoming increasingly clear that the gut microbiome plays an important role in a host of activities including digestion, protection from potentially pathogenic organisms, and the regulation and development of the host immune system. The complex interactions between microbes and host combined with recent clinical observations and epidemiologic trends may point to the convergence of two well-supported (though imperfect) hypotheses: the "hygiene hypothesis" and the "fetal programming hypothesis." We are beginning to understand that exposure to microbes before conception, during gestation, and in the neonatal period have profound effects on the developing immune system. Recent observations from a variety of fields help support the expansion of the "fetal programming hypothesis" to a host-microbe corollary that microbe-host interactions at critical windows influence the future immune phenotype, the maintenance of immune health, and the development of immune-mediated disease.

Environmental toxicants and the developing immune system: a missing link in the global battle against infectious disease?

There is now compelling evidence that developmental exposure to chemicals from our environment contributes to disease later in life, with animal models supporting this concept in reproductive, metabolic, and neurodegenerative diseases. In contrast, data regarding how developmental exposures impact the susceptibility of the immune system to functional alterations later in life are surprisingly scant. Given that the immune system forms an integrated network that detects and destroys invading pathogens and cancer cells, it provides the body's first line of defense. Thus, the consequences of early life exposures that reduce immune function are profound. This review summarizes available data for pollutants such as cigarette smoke and dioxin-like compounds, which consistently support the idea that developmental exposures critically impact the immune system. These findings suggest that exposure to common chemicals from our daily environment represent overlooked contributors to the fact that infectious diseases remain among the top five causes of death worldwide.

Impact of smoking on inflammation: overview of molecular mechanisms

BACKGROUND

Inflammation is a critical component of normal tissue repair, as well as being fundamental to the body's defense against infection. Environmental factors, such as smoking, have been reported to modify the host response and hence modify inflammation progression, severity and outcome. Therefore, a comprehensive understanding of the molecular mechanisms by which smoking affects inflammation is vital for preventive and therapeutic strategies on a clinical level.

AIM

The purpose of the present article is to review the potential biological mechanisms by which smoking affects inflammation, emphasizing recent developments.

RESULTS

Smoking is reported to effect a number of biological mediators of inflammation through its effect on immune-inflammatory cells, leading to an immunosuppressant state. Recent evidence strongly suggests that the molecular mechanisms behind the modulation of inflammation by smoking mainly involve the nuclear factor-kappa B (NF-kB) family, through the activation of both an inhibitor of IkB kinase (IKK)-dependent and -independent pathway. In addition to NF-kB activation, a number of transcriptional factors including GATA, PAX5 and Smad 3/4, have also been implicated.

CONCLUSION

Multiple mechanisms may be responsible for the association of smoking and inflammation, and the identification of potential therapeutic targets should guide future research.

Lifetime exposure to cigarette smoking and the development of adult-onset atopic dermatitis

BACKGROUND

Adult-onset atopic dermatitis (AD) has recently been recognized as a distinct disease entity, but its risk factors have not yet been clearly defined. Although gestational and perinatal exposure to tobacco smoking may be associated with the development of classic AD, the association between active/passive smoking and adult-onset AD remains controversial.

OBJECTIVES

To determine if exposure to smoking, including environmental tobacco smoke (ETS), is associated with the risk of adult-onset AD.

METHODS

Tobacco smoking and exposure to ETS were measured in a case-control association analysis in 83 patients with physician-diagnosed adult-onset AD and 142 age- and sex-matched controls.

RESULTS

Multiple logistic regression analyses showed that, among the potential environmental risk factors, both current and ever smoking were significant risk factors for adult-onset AD [odds ratio (OR) 4·994 and 3·619, respectively], compared with never smoking. Also, packs per year was significantly associated with adult-onset AD (OR 1·058, 95% confidence interval 1·028-1·089), suggesting a lifelong cumulative risk in current smokers. Moreover, nonsmokers with adult-onset AD reported significantly more exposure to ETS.

CONCLUSIONS

Early and/or current exposure to cigarette smoking may contribute cumulatively to the development of adult-onset AD. Exposure to ETS in childhood is associated with the development of adult-onset AD. Adults should be discouraged from smoking to prevent adult-onset AD in themselves and their family members.

Early life environment and developmental immunotoxicity in inflammatory dysfunction and disease

Components of the innate immune system such as macrophages and dendritic cells are instrumental in determining the fate of immune responses and are, also, among the most sensitive targets of early life environmental alterations including developmental immunotoxicity (DIT). DIT can impede innate immune cell maturation, disrupt tissue microenvironment, alter immune responses to infectious challenges, and disrupt regulatory responses. Dysregulation of inflammation, such as that observed with DIT, has been linked with an increased risk of chronic inflammatory diseases in both children and adults. In this review, we discuss the relationship between early-life risk factors for innate immune modulation and promotion of dysregulated inflammation associated with chronic inflammatory disease. The health risks from DIT-associated inflammation may extend beyond primary immune dysfunction to include an elevated risk of several later-life, inflammatory-mediated diseases that target a wide range of physiological systems and organs. For this reason, determination of innate immune status should be an integral part of drug and chemical safety evaluation.

Neonatal immune function and inflammatory illnesses in later life: lessons to be learnt from the developing world?

With the emergence of allergic and autoimmune diseases in populations that have started to transit to a western lifestyle, there has been an increasing interest in the role of environmental factors modulating early immune function. Yet, most of the information concerning neonatal immune function has been derived from studies in westernized countries. We postulate that comparative studies of early immune development in children born under conditions that are typical for a westernized vs. that of a still more traditional setting will provide a crucial insight into the environmental-driven immunological mechanisms that are responsible for the world-wide rise in inflammatory disorders. In this review, we summarize the current understanding of early-life immune function in humans in general and the literature on some major lifestyle factors that may influence neonatal immune function and potentially the risk for disease in later life. An understanding of the mechanisms of 'prenatal/early-life programming' in populations living in traditional compared with modern societies is crucial to develop strategies to prevent a further rise in 'western diseases' such as allergic disorders. Indications exist that prenatal conditioning of the innate immune system by low-grade inflammatory responses is key to inducing more tightly regulated postnatal adaptive immune responses.

Investigation of Toll-like receptors in the pathogenesis of fibrotic and granulomatous disorders: a bronchoalveolar lavage study

Background and aim

Toll-like receptors (TLRs), a key component of innate immunity, have recently been implicated in the pathogenesis of interstitial lung diseases (ILDs). As the involvement of TLRs has not yet been fully elucidated, the aim of the current study was to examine the expression of various TLRs in the bronchoalveolar lavage fluid (BALF) of patients with ILDs.

Patients and Methods

We studied prospectively three groups of patients: (1) one group of 35 patients with fibrotic disorders, 16 with idiopathic pulmonary fibrosis (IPF) and 19 with fibrotic interstitial pneumonias associated with collagen tissue disorders (CTD-IPs); (2) one group of 14 patients with pulmonary sarcoidosis; and (3) 11 normal subjects. We evaluated TLR expression with flow cytometry and mRNA expression with real-time PCR.

Results

An overexpression of TLR-3 mRNA was found in fibrotic disorders (CTD-IPs/IPF) in comparison with sarcoidosis (mean ± SD, 1.104 ± 1.087 versus 0.038 ± 0.03; P = 0.04). Additionally, TLR-3 mRNA was increased in CTD-IPs in comparison with IPF (P = 0.001), sarcoidosis (P = 0.002) and controls (P = 0.05). An upregulation in TLR-7 and -9 mRNA expression was detected in IPF (P = 0.05) and sarcoidosis (P = 0.05), respectively, when compared to controls. A higher percentage of TLR-9-expressing cells was found in BALF of CTD-IPs when compared to IPF (mean ± SD, 36.7 ± 7.06 versus 14.85 ± 3.82; P = 0.025).

Conclusion

We observed distinct profiles of TLR expression in fibrotic and granulomatous disorders. It is likely that they could play a key role in the pathogenesis of these diseases and represent future therapeutic targets.

Selective Toll--like receptor expression in human fetal lung

Toll-like receptors (TLRs) are critical components of the innate immune system, acting as pattern recognition molecules and triggering an inflammatory response. TLR associated gene products are of interest in modulating inflammatory-related pulmonary diseases of the neonate. The ontogeny of TLR-related genes in human fetal lung has not been previously described and could elucidate additional functions and identify strategies for attenuating the effects of fetal inflammation. We examined the expression of 84 TLR-related genes on 23 human fetal lung samples from three groups with estimated ages of 60 (57-59 d), 90 (89-91 d), and 130 (117-154 d) d. By using a false detection rate algorithm, we identified 32 genes displaying developmental regulation with TLR2 having the greatest up-regulation of TLR genes (9.2-fold increase) and TLR4 unchanged. We confirmed the TLR2 up-regulation by examining an additional 133 fetal lung tissue samples with a fluorogenic polymerase chain reaction assay (TaqMan) and found an exponential best-fit curve during the study time. The best-fit curve predicts a 6.1-fold increase from 60 to 130 d. We conclude that TLR2 is developmentally expressed from the early pseudoglandular stage of lung development to the canalicular stage.

Production of interleukin-5, -10 and interferon-γ in cord blood is strongly associated with the season of birth

BACKGROUND

The effect of labour and different labour-related factors on the cord blood (CB) cell cytokine production is still relatively unknown.

OBJECTIVE

To study the relationships between the production of IL-5, IL-10 and IFN-γ in CB samples and maternal, early neonatal and birth-related factors.

METHODS

Whole-blood samples were collected after birth (n=423) and they were stimulated for 24 and 48 h with a combination of phorbol ester and ionomycin. Production of IL-5, IL-10 and IFN-γ was determined using ELISA. Maternal, early neonatal and birth-related variables were recorded prospectively during pregnancy, and during and after delivery.

RESULTS

After multivariable adjustment for confounders, the strongest predictor of IL-5, IL-10 and IFN-γ production in CB cell samples was the season of birth. Children born in the spring had significantly lower cytokine responses compared with those born in the fall. IL-5 production was inversely associated with female gender of the child and maternal smoking. If corrections for white blood cell (WBC) counts were not performed, IL-5 production was also significantly associated with the mode of delivery. Respectively, the production of IL-10 and IFN-γ was inversely associated with prostaglandin induction before birth.

CONCLUSION

Environmental exposure to pollen and ultraviolet irradiation during gestation may have an effect on the cytokine profile of the offspring in CB because children born in the spring or winter showed the lowest IL-5, IL-10 and IFN-γ responses. The production of IL-10 and IFN-γ was also inversely associated with prostaglandin labour induction before birth. Other labour-related factors were not significantly associated with production of IL-5, IL-10 and IFN-γ after WBC count correction.

Allergic disease: understanding how in utero events set the scene

Events and exposures in pregnancy can have critical effects on fetal development with lasting implications for subsequent health and disease susceptibility. There is growing interest in how modern environmental changes influence fetal immune development and contribute to the recent epidemic of allergy and other immune disorders. Rising rates of allergic disease in early infancy, together with pre-symptomatic differences in immune function at birth, suggest that antenatal events play a predisposing role in the development of disease. A number of environmental exposures in pregnancy can modify neonatal immune function including diet, microbial exposure and maternal smoking, and there is emerging evidence from animal models that these factors may have epigenetic effects on immune gene expression and disease susceptibility. Furthermore, functional genetic polymorphisms also alter individual vulnerability to the effects of these environmental exposures, highlighting the complexity of gene-environmental interactions in this period. All these observations underscore the need for ongoing research to understand the pathogenesis and rising incidence of disease in the hope of better strategies to reverse this.

99th Dahlem conference on infection, inflammation and chronic inflammatory disorders: neonatal immune function and vaccine responses in children born in low-income versus high-income countries

There is increasing evidence that the functional state of the immune system at birth is predictive of the kinetics of immune maturation in early infancy. Moreover, this maturation process can have a major impact on early vaccine responses and can be a key determinant of risk for communicable and non-communicable diseases in later life. We hypothesize that environmental and genetic factors that are often typical for poor-resource countries may have an important impact on prenatal immune development and predispose populations in low-income settings to different vaccine responses and disease risks, compared to those living in high-income countries. In this paper we aimed to summarize the major differences between neonatal and adult immune function and describe what is known so far about discrepancies in immune function between newborns in high- and low-income settings. Further, we discuss the need to test the immunological feasibility of accelerated vaccination schedules in high-risk populations and the potential of variation in disease specific and non-specific vaccine effects.