Lesson from the farm environment

Neonatal necrotizing enterocolitis attenuates adult asthma via eosinophil ferroptosis

BACKGROUND

Necrotizing enterocolitis (NEC) is a severe gastrointestinal disorder primarily affecting preterm infants. Early-life exposure to NEC may influence asthma severity in adulthood through various mechanisms, yet significant research gaps remain in animal model studies of this relationship. This study aims to elucidate preliminary findings that early NEC exposure may attenuate subsequent asthma-related inflammation via animal models and proposes eosinophil ferroptosis as a potential mechanism underlying this effect.

METHODS

NEC was induced in neonatal C57/BL6 mice, followed by ovalbumin (OVA)-sensitized asthma model induction in adulthood. Comprehensive evaluations were performed using lung histopathology, immune cell profiling, lipidomics, and transcriptomics. Transmission electron microscopy, lipid peroxidation assays, and ferroptosis-related protein expression analyses were employed to validate eosinophil ferroptosis. Ferroptosis modulators were tested in NEC/asthma mice. Ferroptosis activator/inhibitor-pretreated eosinophils were infused into asthmatic mice lungs through bronchial instillation to assess their impact on asthma severity in vivo.

RESULTS

NEC-exposed mice exhibited alveolar simplification and inflammatory exudation as primary lung pathological changes. Persistent lipid metabolic dysregulation and reduced pulmonary eosinophils were observed in NEC-exposed mice, persisting into adulthood asthma. In adult asthma models, NEC pretreatment significantly alleviated airway inflammation, mucus secretion, and collagen deposition. NEC exerted protective effects by inducing eosinophil ferroptosis, characterized by mitochondrial atrophy, elevated lipid peroxidation, and altered ferroptosis-related protein expression. Transcriptomic analysis revealed downregulated inflammatory pathway genes and upregulated cilia motility-related genes in NEC-exposed asthmatic mice. Ferroptosis inhibitors significantly suppressed intestinal inflammation in NEC and pulmonary inflammation in asthmatic mice, while inhibiting eosinophil ferroptosis. Conversely, ferroptosis activators exacerbated both intestinal and pulmonary inflammation and eosinophil ferroptosis. Eosinophils pretreated with ferroptosis activators, when reinfused into asthmatic mice, synergized with dexamethasone to reduce asthma airway inflammation severity.

CONCLUSION

Early NEC exposure may attenuate asthma severity by triggering eosinophil ferroptosis. This study is the first to propose ferroptosis as a potential link between NEC and asthma alleviation, with causality further validated using ferroptosis modulators and eosinophil-specific ferroptosis regulation experiments. These findings establish a mechanistic framework, providing theoretical support for exploring eosinophil ferroptosis as a new therapeutic target for asthma.

The antiviral effects and underlying mechanisms of probiotics on viral infections

In public health emergencies, viral diseases like influenza and COVID-19 have become a major concern. One of the proposed responses to this concern is the use of probiotics. Probiotics have a potent role in arming our bodies to combat viral infections. They affect the innate and adaptive immune systems in various ways. Accumulating studies has shown that probiotics can reduce the possibility of infection or the duration of respiratory symptoms by modulating the functions of the immune system. This review aims to summarize the impacts of probiotics on respiratory viral infections and their potential antiviral mechanisms. Therefore, we herein discussed probiotics in relation to lung immunity, distinct types of respiratory viral infections (VRIs), including influenza, rhinoviruses, respiratory syncytial virus, and upper respiratory viral infections, and lastly, probiotics and their effects on COVID-19. However, more studies are needed to explore the antiviral mechanisms of probiotics.

Oral Administration of Live and Dead Cells of Lactobacillus sakei proBio65 Alleviated Atopic Dermatitis in Children and Adolescents: a Randomized, Double-Blind, and Placebo-Controlled Study

Several studies suggest that probiotics might be useful in the management of atopic dermatitis (AD). However, the efficacy and comparison between both the administration of viable and non-viable probiotics on alleviation of AD is not well studied. Therefore, the purpose of this study was to evaluate the effect of L. sakei proBio65 live and dead cells when administered (1 × 10¹⁰ cells/day) for 12 weeks to children and adolescents (aged 3 to 18) with atopic dermatitis. In this randomized double-blind, placebo-controlled study, ninety patients were recruited and randomly allocated to either the L. sakei proBio65 live cells, L. sakei proBio65 dead cells, or placebo groups. Assessment of efficacy was based on the change in SCORing Atopic Dermatitis (SCORAD) score, Investigators Global Assessment (IGA) score, serum inflammatory markers such as the serum eosinophil (count), IgE, eosinophil cationic protein (ECP), CCL17 (thymus and activation-regulated chemokine [TARC]), and CCL27 (cutaneous T cell-attracting chemokine [CTACK]), and changes in skin condition (moisture and sebum) at baseline, week 6 and week 12. The SCORAD total score decreased in the live cells (p = 0.0015) and dead cell group (p = 0.0017) from the baseline after 12 weeks, whereas there were no significant changes in the placebo group when compared with baseline. The skin sebum content increased in both the live cell (p < 0.0001) and the dead cell group (p < 0.0001), suggesting potential improvements in skin barrier functions. Current data suggested a positive improvement in alleviation of AD symptoms upon oral administration of L. sakei proBio65 in both viable and non-viable forms.

Respiratory diseases and allergy in farmers working with livestock: a EAACI position paper

Farmers constitute a large professional group worldwide. In developed countries farms tend to become larger, with a concentration of farm operations. Animal farming has been associated with negative respiratory effects such as work-related asthma and rhinitis. However, being born and raised or working on a farm reduces the risk of atopic asthma and rhinitis later in life. A risk of chronic bronchitis and bronchial obstruction/COPD has been reported in confinement buildings and livestock farmers. This position paper reviews the literature linking exposure information to intensive animal farming and the risk of work-related respiratory diseases and focuses on prevention. Animal farming is associated with exposure to organic dust containing allergens and microbial matter including alive microorganisms and viruses, endotoxins and other factors like irritant gases such as ammonia and disinfectants. These exposures have been identified as specific agents/risk factors of asthma, rhinitis, chronic bronchitis, COPD and reduced FEV₁. Published studies on dust and endotoxin exposure in livestock farmers do not show a downward trend in exposure over the last 30 years, suggesting that the workforce in these industries is still overexposed and at risk of developing respiratory disease. In cases of occupational asthma and rhinitis, avoidance of further exposure to causal agents is recommended, but it may not be obtainable in agriculture, mainly due to socio-economic considerations. Hence, there is an urgent need for focus on farming exposure in order to protect farmers and others at work in these and related industries from developing respiratory diseases and allergy.

The Beneficial Effect of Farm Milk Consumption on Asthma, Allergies, and Infections: From Meta-Analysis of Evidence to Clinical Trial

The low prevalence of asthma and allergies in farm children has partially been ascribed to the consumption of raw cow's milk. A literature search identified 12 publications on 8 pertinent studies. A meta-analysis corroborated the protective effect of raw milk consumption early in life (<1 to 5 years, according to study) on asthma (odds ratio [OR], 0.58; 95% CI, 0.49-0.69), current wheeze (OR, 0.66; 95% CI, 0.55-0.78), hay fever or allergic rhinitis (OR, 0.68; 95% CI, 0.57-0.82), and atopic sensitization (OR, 0.76; 95% CI, 0.62-0.95). The effect particularly on asthma was observed not only in children raised on farms (OR, 0.62; 95% CI, 0.58-0.82) but also in children living in rural areas but not on a farm (OR, 0.60; 95% CI, 0.48-0.74). This demonstrates that the effect of farm milk consumption is independent of other farm exposures and that children not living on a farm can theoretically profit from this effect. Because of the minimal but real risk of life-threatening infections, however, consumption of raw milk and products thereof is strongly discouraged. Raw farm milk and industrially processed milk differ in many instances including removal of cellular components, manipulation of the fat fraction, and various degrees of heating. Preliminary evidence attributes the effect to heat-labile molecules and components residing in the fat fraction. The Milk Against Respiratory Tract Infections and Asthma (MARTHA) trial is currently testing the protective effect of microbiologically safe, minimally processed cow's milk against standard ultra-heat-treated milk in children from 6 months to 3 years with the primary outcome of an asthma diagnosis until age 5 years. If successful, this approach might provide a simple but effective prevention strategy.

Oral Aspects Identified in Atopic Dermatitis Patients: A Literature Review

Introduction:

Atopic dermatitis is a chronic inflammatory skin condition that is more prevalent in children (10-20% of the world's population) than in adults. As its etiology is multifactorial, it is important to know the most frequent oral manifestations in atopic dermatitis patients.

Methodology:

In the last decades, the correlation between atopic dermatitis and conditions and/or changes in the oral cavity has been demonstrated by several studies. The objective of this paper was to describe, through a review of the literature, the oral health conditions and/or oral aspects identified in patients with atopic dermatitis.

Search Strategy:

A descriptive literature review was carried out through a bibliographical survey based on the last 10 years, in order to answer the study questions.

Results:

As a result, we found six studies with different sample sizes, ranging from 43 to 468 patients, and the majority of them were of cross-sectional study design.

Discussion:

Two studies performed their analysis through dental exams and reported that patients with atopic dermatitis tend to have a greater frequency of carious lesions, and two studies correlated Candida with atopic dermatitis through mycological analyzes.

Conclusion:

There are a few studies in the literature that identify the oral aspects of atopic dermatitis. More investigations are needed in order to contribute to the knowledge of such oral aspects and the approach to treat these patients regarding oral health.

Prevention of allergies in childhood - where are we now?

Allergic diseases represent an increasing health problem for children worldwide. Along with allergic airway diseases, food allergy comes to the fore and herewith closely intertwined the hypothesis that an early allergic sensitization might occur via skin barrier defect(s). The importance of the skin barrier has been documented by several studies meanwhile. Not only genetic studies screen the associations between Filaggrin loss-of-function mutations, atopic dermatitis, allergic sensitization, food allergy and even airway diseases, but also epidemiological studies cast new light on the hypothesis of the atopic march. As another focus in context of the development of an allergic phenotype, the specific microbial exposure with all its diversities has been crystallized as it shapes the immune system in (early) infancy. Studies explored both, the role of human intestinal microbiota as well as the external microbial diversity. Unfortunately suitable markers for atopic predictors are still rare. New studies point out that specific IgE antibodies (e.g., IgE to Phl p 1) in children without allergic symptoms so far, might function as a pre-clinical biomarker, which may help to identify candidates for primary (allergen non-specific) or secondary (allergen-specific) prevention in terms of specific immunoprophylaxis. These manifold research activities document a complex increase in knowledge. Nevertheless new assumptions need to be substantively confirmed in order to finally generate the urgently needed preventive strategies for allergic diseases in childhood.

Microbes and asthma: Opportunities for intervention

The worldwide incidence and prevalence of asthma continues to increase. Asthma is now understood as an umbrella term for different phenotypes or endotypes, which arise through different pathophysiologic pathways. Understanding the many factors contributing to development of the disease is important for the identification of novel therapeutic targets for the treatment of certain asthma phenotypes. The hygiene hypothesis has been formulated to explain the increasing prevalence of allergic disease, including asthma. This hypothesis postulates that decreased exposure at a young age to certain infectious agents as a result of improved hygiene, increased antibiotic use and vaccination, and changes in lifestyle and dietary habits is associated with changes in the immune system, which predispose subjects to allergy. Many microbes, during their coevolution with human subjects, developed mechanisms to manipulate the human immune system and to increase their chances of survival. Improving models of asthma, as well as choosing adequate end points in clinical trials, will lead to a more complete understanding of the underlying mechanisms, thus providing an opportunity to devise primary and secondary interventions at the same time as identifying new molecular targets for treatment. This article reports the discussion and conclusion of a workshop under the auspices of the Netherlands Lung Foundation to extend our understanding of how modulation of the immune system by bacterial, parasitic, and viral infections might affect the development of asthma and to map out future lines of investigation.

A specific hygiene hypothesis

Allergic diseases have reached epidemic proportions in Western populations in the last several decades. The hygiene hypothesis proposed more than twenty years ago has helped us to understand the epidemic and has been verified with numerous studies. However, translational measures deduced from these studies to prevent allergic diseases have not proven effective. Recent studies on immigrants' allergies and any potential association between oral infection and allergic diseases prompt me to propose a specific hygiene hypothesis to explain how oral hygiene practices might have contributed to the uprising of hay fever, the most common allergic disease. The historic oral hygiene level in US is closely associated with the emerging allergic epidemic. Future studies to test the hypothesis are needed and verification of the hypothesis can potentially yield highly effective measures to prevent allergic diseases.

Milk: a postnatal imprinting system stabilizing FoxP3 expression and regulatory T cell differentiation

BACKGROUND

Breastfeeding has protective effects for the development of allergies and atopy. Recent evidence underlines that consumption of unboiled farm milk in early life is a key factor preventing the development of atopic diseases. Farm milk intake has been associated with increased demethylation of FOXP3 and increased numbers of regulatory T cells (Tregs). Thus, the questions arose which components of farm milk control the differentiation and function of Tregs, critical T cell subsets that promote tolerance induction and inhibit the development of allergy and autoimmunity.

FINDINGS

Based on translational research we identified at least six major signalling pathways that could explain milk's biological role controlling stable FoxP3 expression and Treg differentiation: (1) via maintaining appropriate magnitudes of Akt-mTORC1 signalling, (2) via transfer of milk fat-derived long-chain ω-3 fatty acids, (3) via transfer of milk-derived exosomal microRNAs that apparently decrease FOXP3 promoter methylation, (4) via transfer of exosomal transforming growth factor-β, which induces SMAD2/SMAD3-dependent FoxP3 expression, (5) via milk-derived Bifidobacterium and Lactobacillus species that induce interleukin-10 (IL-10)-mediated differentiation of Tregs, and (6) via milk-derived oligosaccharides that serve as selected nutrients for the growth of bifidobacteria in the intestine of the new born infant.

CONCLUSION

Accumulating evidence underlines that milk is a complex signalling and epigenetic imprinting network that promotes stable FoxP3 expression and long-lasting Treg differentiation, crucial postnatal events preventing atopic and autoimmune diseases.

Increased respiratory symptoms in COPD patients living in the vicinity of livestock farms

Several studies have investigated the effect of livestock farm emissions on the respiratory health of local residents, but results are inconsistent. This study aims to explore associations between the presence of livestock farms and respiratory health in an area of high-density livestock farming in the Netherlands. We focused especially on associations between farm exposures and respiratory symptoms within subgroups of potentially susceptible patients with a pre-existing lung disease.In total, 14 875 adults (response rate 53.4%) completed a questionnaire concerning respiratory health, smoking habits and personal characteristics. Different indicators of livestock farm exposures relative to the home address were computed using a geographic information system.Prevalence of chronic obstructive pulmonary disease (COPD) and asthma was lower among residents living within 100 m of a farm (OR 0.47, 95% CI 0.24-0.91 and OR 0.65, 95% CI 0.45-0.93, respectively). However, >11 farms in 1000 m compared to fewer than four farms in 1000 m (fourth quartile versus first quartile) was associated with wheezing among COPD patients (OR 1.71, 95% CI 1.01-2.89). Using general practitioners' electronic medical records, we demonstrated that selection bias did not affect the observed associations.Our data suggest a protective effect of livestock farm emissions on the respiratory health of residents. Nonetheless, COPD patients living near livestock farms reported more respiratory symptoms, suggesting an increased risk of exacerbations.

The rural-urban enigma of allergy: what can we learn from studies around the world?

Childhood asthma and related allergic conditions have become the most common chronic disorders in the Western world. Many studies from around the world have demonstrated an increasing trend of asthma prevalence over the last few decades (Lancet, 368, 2004, 733). A few recent reports also suggested that childhood asthma prevalence may be showing a plateau or even a decline in few developed countries. Given the rapid changes in the prevalence over a short period of time, environmental factors are the more likely candidates explaining such trend. One of the most consistent epidemiological findings was that subjects living in the rural areas had lower prevalence of allergies when compared to those from urban areas (Clin Exp Allergy 30, 2000, 187; Pediatr Pulmonol 44, 2009, 793). Clear understanding of the mechanisms of how the environmental determinants in the rural environment may affect the early immune system resulting in lower risk of allergies and asthma will facilitate the development of future primary preventive strategies. In this study, we review recent data from around the world and explore the epidemiology and mechanistic studies that may explain the rural-urban difference of allergies.

Allergy in children in hand versus machine dishwashing

BACKGROUND AND OBJECTIVE

The hygiene hypothesis stipulates that microbial exposure during early life induces immunologic tolerance via immune stimulation, and hence reduces the risk of allergy development. Several common lifestyle factors and household practices, such as dishwashing methods, may increase microbial exposure. The aim of this study was to investigate if such lifestyle factors are associated with allergy prevalence.

METHODS

Questionnaire-based study of 1029 children aged 7 to 8 years from Kiruna, in the north of Sweden, and Mölndal, in the Gothenburg area on the southwest coast of Sweden. Questions on asthma, eczema, and rhinoconjunctivitis were taken from the International Study of Asthma and Allergies in Childhood questionnaire.

RESULTS

Hand dishwashing was associated with a reduced risk of allergic disease development (multivariate analysis, odds ratio 0.57; 95% confidence interval: 0.37-0.85). The risk was further reduced in a dose-response pattern if the children were also served fermented food and if the family bought food directly from farms.

CONCLUSIONS

In families who use hand dishwashing, allergic diseases in children are less common than in children from families who use machine dishwashing. We speculate that a less-efficient dishwashing method may induce tolerance via increased microbial exposure.

Farm characteristics, allergy symptoms, and risk of non-hodgkin lymphoid neoplasms in the agricultural health study

BACKGROUND

Because of unique exposures, studies among farmers may yield insights into the relationship between allergies and non-Hodgkin lymphoid (NHL) neoplasms. We evaluated farm characteristics, allergic symptoms and conditions, and risk of NHL including specific subtypes in the Agricultural Health Study, a prospective cohort of farmers and spouses from North Carolina and Iowa.

METHODS

We identified 710 incident cases of NHL (including chronic lymphocytic leukemia and multiple myeloma) among 82,370 participants with baseline data on crop and animal exposures, including 454 cases among 52,850 participants with baseline data on recent allergy symptoms (rhinitis) and living on a farm during childhood. HR and 95% confidence intervals (CI) were calculated using multivariable-adjusted proportional hazards models.

RESULTS

We observed reduced risks of NHL among farmers and spouses with rhinitis at baseline (HR, 0.63; 95% CI, 0.51-0.79), related to growing soybeans (HR, 0.80; 95% CI, 0.67-0.96), and among farmers who handled stored grains or hay (HR, 0.66; 95% CI, 0.52-0.82). Growing up on a farm was associated with increased NHL risk (HR, 1.51; 95% CI, 1.15-1.98). Results did not differ significantly by NHL subtype.

CONCLUSIONS

Both the reduced risk of NHL among those with allergy symptoms and specific farm exposures in adulthood, and the increased risk among those who grew up on a farm suggest that the host immune response to agricultural allergens may influence NHL development.

IMPACT

This prospective study is, to our knowledge, the first to investigate the relationship between allergy symptoms and NHL risk in farmers; confirmation of these findings in other farming populations is warranted. Cancer Epidemiol Biomarkers Prev; 24(3); 587-94. ©2015 AACR.

The potential mechanistic link between allergy and obesity development and infant formula feeding

This article provides a new view of the cellular mechanisms that have been proposed to explain the links between infant formula feeding and the development of atopy and obesity. Epidemiological evidence points to an allergy- and obesity-preventive effect of breastfeeding. Both allergy and obesity development have been traced back to accelerated growth early in life. The nutrient-sensitive kinase mTORC1 is the master regulator of cell growth, which is predominantly activated by amino acids. In contrast to breastfeeding, artificial infant formula feeding bears the risk of uncontrolled excessive protein intake overactivating the infant's mTORC1 signalling pathways. Overactivated mTORC1 enhances S6K1-mediated adipocyte differentiation, but negatively regulates growth and differentiation of FoxP3(+) regulatory T-cells (Tregs), which are deficient in atopic individuals. Thus, the "early protein hypothesis" not only explains increased mTORC1-mediated infant growth but also the development of mTORC1-driven diseases such as allergy and obesity due to a postnatal deviation from the appropriate axis of mTORC1-driven metabolic and immunologic programming. Remarkably, intake of fresh unpasteurized cow's milk exhibits an allergy-preventive effect in farm children associated with increased FoxP3(+) Treg numbers. In contrast to unprocessed cow's milk, formula lacks bioactive immune-regulatory microRNAs, such as microRNA-155, which plays a major role in FoxP3 expression. Uncontrolled excessive protein supply by formula feeding associated with the absence of bioactive microRNAs and bifidobacteria in formula apparently in a synergistic way result in insufficient Treg maturation. Treg deficiency allows Th2-cell differentiation promoting the development of allergic diseases. Formula-induced mTORC1 overactivation is thus the critical mechanism that explains accelerated postnatal growth, allergy and obesity development on one aberrant pathway.

Milk: an exosomal microRNA transmitter promoting thymic regulatory T cell maturation preventing the development of atopy?

Epidemiological evidence confirmed that raw cow's milk consumption in the first year of life protects against the development of atopic diseases and increases the number of regulatory T-cells (Tregs). However, milk's atopy-protective mode of action remains elusive.This review supported by translational research proposes that milk-derived microRNAs (miRs) may represent the missing candidates that promote long-term lineage commitment of Tregs downregulating IL-4/Th2-mediated atopic sensitization and effector immune responses. Milk transfers exosomal miRs including the ancient miR-155, which is important for the development of the immune system and controls pivotal target genes involved in the regulation of FoxP3 expression, IL-4 signaling, immunoglobulin class switching to IgE and FcϵRI expression. Boiling of milk abolishes milk's exosomal miR-mediated bioactivity. Infant formula in comparison to human breast- or cow's milk is deficient in bioactive exosomal miRs that may impair FoxP3 expression. The boost of milk-mediated miR may induce pivotal immunoregulatory and epigenetic modifications required for long-term thymic Treg lineage commitment explaining the atopy-protective effect of raw cow's milk consumption.The presented concept offers a new option for the prevention of atopic diseases by the addition of physiological amounts of miR-155-enriched exosomes to infant formula for mothers incapable of breastfeeding.

Efficacy of Probiotic Therapy on Atopic Dermatitis in Children: A Randomized, Double-blind, Placebo-controlled Trial

Purpose

To evaluate a therapeutic efficacy of probiotics mixture (probiotics) in the treatment of children with mild-to-moderate atopic dermatitis (AD).

Methods

Randomized, double-blind, placebo-controlled, parallel trial with a washout period of 2 weeks and an intervention period for 6 weeks, conducted from November 2010 to October 2011. One hundred children with mild to moderate AD (2-9 years old) were randomly allocated to the probiotics (Lactobacilluss casei, Lactobacillus rhamnosus, Lactobacillus plantarum, and Bifidobacterium lactis) or placebo groups. The assessment of efficacy was based on the change in eczema area severity index (EASI), visual analogue scale for pruritus (VASP), fecal cell counts of each strains (log10[cell counts/g stool]), and serum cytokine levels (Interleukin-4 [IL-4]; IL-10; Tumor necrosis factor alpha, [TNF-α]) in weeks 0 and 6.

Results

Demographics and baseline characteristics at the week 0 were not significantly different between the 2 groups. The significant increments in fecal-cell counts were observed in the probiotcs group at week 6 (P=0.00), while the cytokine levels between the 2 groups were not significantly different in week 6 (IL-4, P=0.50; IL-10, P=0.58; TNF-α, P=0.82). The probiotics significantly improved clinical severity after 6 weeks' intervention of probiotics; however, the placebo group also showed significant improvement (EASI; P=0.00, VASP; P=0.00).

Conclusions

Our findings showed that probiotics successfully colonized in the intestine after 6 weeks' intervention; nevertheless, we could not find an additional therapeutic or immunomodulatory effects on the treatment of AD. Further long-term studies will be necessary to clarify the therapeutic efficacy of probiotics.

Regulation of TH17 markers early in life through maternal farm exposure

BACKGROUND

Previous studies suggested that maternal farm exposure during pregnancy modulates early immune development toward an allergy-protective status potentially mediated by TH1 or regulatory T (Treg) cells. However, the underlying mechanisms might involve immune modulation of additional T-cell populations, such as TH17 cells, influenced by genetic predisposition.

OBJECTIVE

We examined the role of maternal farm exposure and genetic predisposition on TH17 cell responses to innate and adaptive immune stimulation in cord blood.

METHODS

Eighty-four pregnant mothers were recruited before delivery. Detailed questionnaires (60 nonfarming mother, 22 farming mothers, and 2 exclusions) assessed farming exposures. Cord blood was stimulated with lipid A, peptidoglycan (Ppg), or PHA. TH17 lineage (retinoic acid receptor-related orphan receptor C [RORC], retinoic acid receptor-related orphan receptor α [RORA], IL-23 receptor [IL23R], IL17, IL17F, and IL22) and Treg cell markers (forkhead box protein 3 [FOXP3], lymphocyte activation gene 3 [LAG3], and glucocorticoid-induced TNF receptor [GITR]) were assessed at the mRNA level. TH17/Treg/TH1/TH2 cytokines and 7 single nucleotide polymorphisms within the TH17 lineage (RORC, IL23R, and IL17) were examined.

RESULTS

TH17 lineage mRNA markers were expressed at birth at low concentrations independent of maternal farm exposure. A positive correlation between TH17 lineage markers and FOXP3 (mRNA) was observed on stimulation (nonfarming mothers: lipid A, Ppg, and PHA; farming mothers: Ppg and PHA), influenced by maternal farming. Specific single nucleotide polymorphisms within the TH17 lineage genes influenced gene expression of TH17 and Treg cell markers and cytokine secretion.

CONCLUSIONS

Gene expression of TH17 lineage markers in cord blood was not influenced by maternal farming. Yet TH17 and Treg cell markers were positively correlated and influenced by maternal farm exposure. Our data suggest that prenatal exposures and genetic predisposition play a role during early TH17 immune maturation, potentially regulating the development of immune-mediated diseases, such as childhood asthma.

αβ T cells and a mixed Th1/Th17 response are important in organic dust-induced airway disease

BACKGROUND

Organic dust exposure in agricultural environments induces an inflammatory response that attenuates over time, yet repetitive dust exposures result in chronic lung diseases. Animal models resembling this chronic lung inflammatory response have been developed, yet the underlying cellular mechanisms are not well defined.

OBJECTIVE

Because mice repetitively exposed to organic dust extracts (DE) display increased CD3+ T cell lung infiltrates, we sought to determine the phenotype and importance of these cells.

METHODS

Mice received swine confinement DE repetitively for 3 weeks by established intranasal inhalation protocol. Studies were conducted with peptidoglycan (PGN) because it is a major DE component in large animal farming environments and has shared similar biologic effects with DE. Enumeration of T cells and intracellular cytokine profiles were conducted by flow cytometry techniques. Whole lung homogenate cytokines were analyzed by multiplex immunoassay. T cell receptor (TCR) αβ knockouts were used to determine the functional importance of αβ-expressing T cells.

RESULTS

DE increased lung-associated CD3+CD4+ T cells and interleukin (IL)-17 (but not IL-4, interferon [IFN]-γ, IL-10) producing CD4+ T cells. PGN treatment resulted in increased IL-17 and IFN-γ producing CD4+ T cells and IFN-γ producing CD8+ T cells. Both DE and PGN augmented expression of cytokines associated with Th1 and Th17 polarization in lung homogenates. DE-induced lung mononuclear aggregates and bronchiolar compartment inflammation were significantly reduced in TCR knockout animals; however, neutrophil influx and alveolar compartment inflammation were not affected.

CONCLUSION

Studies demonstrated that DE and PGN exposure promote a Th1/Th17 lung microenvironment and that αβ-expressing T cells are important in mediating DE-induced lung pathologic conditions.