The role of indoor allergens in the development of asthma

Transgenerational impacts of early life adversity: from health determinants, implications to epigenetic consequences

Exposure to different environmental factors, social and socioeconomic factors promotes development of the early-life adversity (ELA) phenotype. The persistence of this phenotype across generations is an interesting phenomenon that remains unexplored. Of late many studies have focused on disease-associated outcomes of ELA following exposure during childhood but the persistence of epigenetic imprints transmitted by ELA exposed parents to their offspring remains poorly described. It is possible that both parents are able to transmit ELA-associated genetic imprints to their offspring via transgenerational inheritance mechanisms. Here, we highlight the role of the mother and father in the biological process of conception, from epigenetic reprogramming cycles to later environmental exposures. We explain some of the known determinants of ELA (pollution, socioeconomic challenges, infections, etc.) and their disease-associated outcomes. Finally, we highlight the role of epigenetics, mitochondria and ncRNAs as mechanisms mediating transgenerational inheritance. Whether these transgenerational inheritance mechanisms occur in the human context remains unclear but there is a large body of suggestive evidence in non-human models that points out to its existence.

Microscopic Menaces: The Impact of Mites on Human Health

Mites are highly prevalent arthropods that infest diverse ecological niches globally. Approximately 55,000 species of mites have been identified but many more are yet to be discovered. Of the ones we do know about, most go unnoticed by humans and animals. However, there are several species from the Acariformes superorder that exert a significant impact on global human health. House dust mites are a major source of inhaled allergens, affecting 10-20% of the world's population; storage mites also cause a significant allergy in susceptible individuals; chiggers are the sole vectors for the bacterium that causes scrub typhus; Demodex mites are part of the normal microfauna of humans and their pets, but under certain conditions populations grow out of control and affect the integrity of the integumentary system; and scabies mites cause one of the most common dermatological diseases worldwide. On the other hand, recent genome sequences of mites provide novel tools for mite control and the development of new biomaterial with applications in biomedicine. Despite the palpable disease burden, mites remain understudied in parasitological research. By better understanding mite biology and disease processes, researchers can identify new ways to diagnose, manage, and prevent common mite-induced afflictions. This knowledge can lead to improved clinical outcomes and reduced disease burden from these remarkably widespread yet understudied creatures.

Risks of adverse childhood experiences on healthcare utilization and outcomes in early childhood

BACKGROUND

The American Academy of Pediatrics recommends all pediatricians to be ready to implement trauma-informed care, including the mitigation of impacts of Adverse Childhood Experiences (ACEs) through screening and identification of at-risk population. Reliable survey tools and knowledge of the consequences of ACEs are needed.

OBJECTIVE

This study examines the healthcare utilization and diagnoses captured in insurance claims in association with the number of ACEs recorded by the Family Map Inventories (FMI). The FMI offers a comprehensive family assessment, which includes child ACEs (FMI-ACEs) using prospective, proxy risk indicators.

PARTICIPANTS AND SETTING

Low-income families (N = 1647) with children aged three to five years who completed the FMI were linked to their insurance records.

METHODS

Multivariable logistic and generalized linear regression models were fitted to explore the association between the number of ACEs (FMI-ACEs scores) and healthcare utilization and health outcomes.

RESULTS

Children were exposed at rates of 32.4 % to zero, 31.7 % to one, 19.7 % to two, and 16.3 % to three or more ACEs. The FMI-ACEs scores were associated with greater use of non-preventive outpatient visits, filled prescriptions, and overall use of healthcare. Incidences of adjustment disorders were 4 times and attention-deficit conducts were 2 times higher among children with the highest FMI-ACEs scores than those with zero FMI-ACEs.

CONCLUSIONS

This study marks the first effort to conduct insurance claims data review to ascertain association between a survey measure of ACEs and health utilization and diagnosed conditions. The association of ACEs risk screening and healthcare utilization and diagnoses was observed.

Causal relationship between Butyricimonas and allergic asthma: a two-sample Mendelian randomization study

Background

Growing evidence has well documented the close association between the gut microbiome and allergic respiratory disease, which has been notably represented by allergic asthma. However, it is unclear whether this association is a causal link. Therefore, we investigated the potential causal associations between the gut microbiome and allergic asthma or other allergic diseases.

Methods

In this study, we performed two-sample Mendelian randomization (MR) analyses by using the publicly available genome-wide association study (GWAS) summary data. Single-nucleotide polymorphisms (SNPs) that significantly correlated were selected as instrumental variables. The inverse variance weighted (IVW) method was used to examine the potential causal gut microbial genera for allergic asthma and other allergic diseases. The robustness of the primary findings of the MR analyses was ensured by using different sensitivity analyses.

Results

Combining the findings from multiple analyses, the host genetic-driven increases in Butyricimonas at the genus level were positively correlated with the risk of allergic asthma. In addition, phylum Bacteroidetes and class Bacteroidia were also found to have negative associations with the risk of allergic asthma; genus Slackia was identified as having potential causal effects with allergic asthma. No clear evidence of pleiotropy and heterogeneity was observed in genus Butyricimonas. Butyricimonas was also found to have an association with allergic rhinitis, but not with other allergic diseases.

Conclusion

Our findings indicate that there are new gut microbial genera that were causally associated with the risk of allergic asthma and other allergic diseases, and offer novel insights into the pathogenesis of allergic respiratory diseases.

Immunomodulatory effects of modified Liu-Wei-Di-Huang-Wan Traditional Chinese medicine on allergic asthmatic mice

BACKGROUND

Allergic asthma occurs worldwide and is particularly prevalent in westernized countries characterized by chronic airway inflammation resulting in airway hyperresponsiveness. The house dust mites (HDM) including Dermatophagoides pteronyssinus are major sources of sensitization and triggering allergic symptoms in asthmatic patients. The Der p 2 is a major allergen and the predominant source of causative respiratory disorders which induce airway inflammation and bronchial constriction in mite-allergic patients. Few studies evaluate the ameliorating effects of modified Liu-Wei-Di-Huang-Wan (modified LWDHW) on allergic asthma.

METHODS

This study aimed to investigate the immunological mechanisms of modified LWDHW on the reductions of airway inflammation, signal transduction, inflammatory cytokine production, Th2 cell proliferation, and bronchial obstruction in Der p 2-induced asthmatic mice.

RESULTS

At least ten active ingredients were contained in the formula of modified LWDHW- 1217A and 1217B. Results showed that the immunoglobulin generations (Der p 2 specific- IgE and IgG1), inflammatory cytokine productions (IL-5 and IL-13) in the Sera and BALF could be down-regulated, and the Th1-cytokine productions (IL-12 and IFN-γ) be increased after immunotherapy with modified LWDHW of 1217A or 1217B. The inflammatory cell infiltrations (macrophages, eosinophils, and neutrophils) in the airway and the expressions of TH2-related genes (IL-4, IL-5, and IL-13), TH2-related transcription factor (GATA-3), and neutrophil chemotactic chemokine (IL-8) in the lung tissue of asthmatic mice were significantly decreased after the immunotherapy. The Th1/Th2 polarization had been identified that the IL-4+/CD4+ T cells were downregulated and IFN-γ+/CD4+ T cells were increased. The airway hyperresponsiveness to methacholine inhalation of Penh values was significantly decreased in the treated groups. There were significant improvements in the bronchus histopathology after immunotherapy with 1217A or 1217B which were evaluated by tracheal thickness, inflammatory cell count, and tracheal rupture of mouse lung.

CONCLUSION

It revealed that 1217A or 1217B could regulate the immune responses and improve pulmonary function. Data suggests that modified LWDHW of 1217A or 1217B have the potential for use as a therapeutic intervention for the treatment of mite allergen Der p 2-induced allergic asthma.

Targeted suppression of Dpt-specific B cells in humanized Rag2- γc- mouse model of HDM allergy

Der p 1 is one of the major allergenic molecules of Dermatophagoides pteronyssinus, causing house dust mite (HDM) allergy. The pathological B cells produce allergen-specific IgE antibodies that mediate the hypersensitivity reaction, therefore the selective elimination of these B cells is a legitimate therapeutic goal in allergy. Chimeric molecule Dp51-72 able to cross-link B cell inhibitory complement receptor type 1 and BCR on Der p 1-specific B cells was constructed. The signalling capabilities of this molecule have been tested on human B cells. A humanized mouse model of HDM allergy has been used to test the in vivo effects of the chimeric molecule administration. Administering the chimeric molecule to immunodeficient Rag2- γc- mice transferred with PBMCs from allergic patients resulted in reduction of allergen-specific IgE antibodies in the sera, and reduced infiltration of immune cells in lung histology preparations. Reduced numbers of human CD45⁺ and CD4⁺ cells in the lungs as well as inhibition of mast cell degranulation were also observed. The treatment with Dp51-72 chimera significantly decreased the local levels of anti-Dpt IgE antibodies in the bronchoalveolar lavage fluid (BALF). The binding of the chimeric molecule to tonsillar B cells triggers the tyrosine phosphorylation of 30-32 kDa protein, which is most likely involved in the inhibitory process. Administration of constructed chimeric molecules to humanized mice with developed inflammation resulted in specific suppression of disease-associated IgE antibody-producing cells and preserved lung histology. This effective approach could be further developed into a therapeutic agent for treatment of patients with HDM allergy.

Environmental Interventions for Asthma

Exposure and sensitization to environmental factors play a fundamental role in asthma development and is strongly associated with asthma morbidity. While hereditary factors are critical determinants of asthma, exposures to environmental factors are implicated in the phenotypic expression of asthma and have been strongly associated in the risk of its development. Significant interest has thus been geared toward potentially modifiable environmental exposures which may lead to the development of asthma. Allergen exposure, in particular indoor allergens, plays a significant role in the pathogenesis of asthma, and remediation is a primary component of asthma management. In the home, multifaceted and multitargeted environmental control strategies have been shown to reduce home exposures and improve asthma outcomes. In addition to the home environment, assessment of the school, daycare, and workplace environments of patients with asthma is necessary to ensure appropriate environmental control measures in conjunction with medical care. This article will discuss the role of the environment on asthma, review targeted environmental therapy, and examine environmental control measures to suppress environmental exposures in the home and school setting.

Der p 38 Is a Bidirectional Regulator of Eosinophils and Neutrophils in Allergy

The house dust mite is the most common cause of allergic diseases, and TLR4 acts as an overarching receptor for allergic responses. This study aimed to identify novel allergen binding to TLR4 in house dust mites and unveil its unique role in allergic responses. Der p 38 was purified and characterized by liquid chromatography tandem mass spectrometry-based peptide mapping. Biolayer interferometry and structure modeling unveiled TLR4-binding activity and the structure of recombinant Der p 38. The allergenicity of Der p 38 was confirmed by a skin prick test, and basophil activation and dot blot assays. The skin prick test identified 24 out of 45 allergic subjects (53.3%) as Der p 38⁺ subjects. Der p 38-augmented CD203c expression was noted in the basophils of Der p 38⁺ allergic subjects. In animal experiments with wild-type and TLR4 knockout BALB/c mice, Der p 38 administration induced the infiltration of neutrophils as well as eosinophils and exhibited clinical features similar to asthma via TLR4 activation. Persistent Der p 38 administration induced severe neutrophil inflammation. Der p 38 directly suppressed the apoptosis of allergic neutrophils and eosinophils, and enhanced cytokine production in human bronchial epithelial cells, inhibiting neutrophil apoptosis. The mechanisms involved TLR4, LYN, PI3K, AKT, ERK, and NF-κB. These findings may contribute to a deep understanding of Der p 38 as a bridge allergen between eosinophilic and neutrophilic inflammation in the pathogenic mechanisms of allergy.

Precision Medicine in Mite Allergic Rhinitis

It is well-known that a correct diagnosis is necessary for effective treatment. In the case of allergic rhinitis due to mites, imprecise diagnosis with effective but improvable methods means that in many cases an optimal result is not reached in patients. The diagnosis of allergic rhinitis due to mite sensitization have to require more homogeneously reproducible diagnostic tests that try to encompass many more of the protein antigens contained in them. With the few proteins that the problem has usually focused on, there is no they would cover many of the clinically relevant allergens in a large proportion of patients. In this mini-review we try to highlight the importance of having good allergenic sources and briefly gather information on various allergenic proteins included in mites that could be clinically relevant. All this to try to get closer to a more accurate diagnosis. We are also talking about two diagnostic tools that are clearly out of use and that should be promoted in the consultations to obtain an even greater and better outcome in patients.

Treatment outcome clustering patterns correspond to discrete asthma phenotypes in children

Despite widely and regularly used therapy asthma in children is not fully controlled. Recognizing the complexity of asthma phenotypes and endotypes imposed the concept of precision medicine in asthma treatment. By applying machine learning algorithms assessed with respect to their accuracy in predicting treatment outcome, we have successfully identified 4 distinct clusters in a pediatric asthma cohort with specific treatment outcome patterns according to changes in lung function (FEV₁ and MEF₅₀), airway inflammation (FENO) and disease control likely affected by discrete phenotypes at initial disease presentation, differing in the type and level of inflammation, age of onset, comorbidities, certain genetic and other physiologic traits. The smallest and the largest of the 4 clusters- 1 (N = 58) and 3 (N = 138) had better treatment outcomes compared to clusters 2 and 4 and were characterized by more prominent atopic markers and a predominant allelic (A allele) effect for rs37973 in the GLCCI1 gene previously associated with positive treatment outcomes in asthmatics. These patients also had a relatively later onset of disease (6 + yrs). Clusters 2 (N = 87) and 4 (N = 64) had poorer treatment success, but varied in the type of inflammation (predominantly neutrophilic for cluster 4 and likely mixed-type for cluster 2), comorbidities (obesity for cluster 2), level of systemic inflammation (highest hsCRP for cluster 2) and platelet count (lowest for cluster 4). The results of this study emphasize the issues in asthma management due to the overgeneralized approach to the disease, not taking into account specific disease phenotypes.

Is early life adversity a trigger towards inflammageing?

There are many 'faces' of early life adversity (ELA), such as childhood trauma, institutionalisation, abuse or exposure to environmental toxins. These have been implicated in the onset and severity of a wide range of chronic non-communicable diseases later in life. The later-life disease risk has a well-established immunological component. This raises the question as to whether accelerated immune-ageing mechanistically links early-life adversity to the lifelong health trajectory resulting in either 'poor' or 'healthy' ageing. Here we examine observational and mechanistic studies of ELA and inflammageing, highlighting common and distinct features in these two life stages. Many biological processes appear in common including reduction in telomere length, increased immunosenescence, metabolic distortions and chronic (viral) infections. We propose that ELA shapes the developing immune, endocrine and nervous system in a non-reversible way, creating a distinct phenotype with accelerated immunosenescence and systemic inflammation. We conclude that ELA might act as an accelerator for inflammageing and age-related diseases. Furthermore, we now have the tools and cohorts to be able to dissect the interaction between ELA and later life phenotype. This should, in the near future, allow us to identify the ecological and mechanistic processes that are involved in 'healthy' or accelerated immune-ageing.

Multigenerational Epigenetic Regulation of Allergic Diseases: Utilizing an Experimental Dust Mite-Induced Asthma Model

Environmental exposures have been linked to increased asthma risk, particularly during pregnancy and in early life. Here we use a mouse model of allergic lung disease to examine the effects of pre- and perinatal house dust mite (HDM) allergen exposure on offspring phenotypic and transcriptional outcomes in three generations. We show that maternal HDM exposure (F0) acts synergistically with adult HDM exposure, leading to enhanced airway hyperresponsiveness (AHR) and lung inflammation when compared to mice exposed solely in adulthood. Additionally, a subset of F1 males were not challenged in adulthood, and used to generate F2 progeny, which was then used to generate F3 progeny. Upon adult challenge to HDM, F2, and F3 males generated from the maternal HDM (F0) exposure lineage displayed increased airway reactivity and inflammation when compared to mice exposed solely in adulthood. These findings indicate that maternal allergen exposure is capable of enhancing either susceptibly to or severity of allergic airway disease. To examine the role of epigenetic inheritance of asthma susceptibility induced by maternal HDM exposure, we utilized a genome-wide MeDIP-seq and hMeDIP-seq analysis to identify genes differentially methylated (DMG) and hydroxymethylated (DHG), and their association with the enhanced AHR. In addition, we validated the relationship between DNA methylation and mRNA expression of the DMGs and DHGs in the male sub-generations (F1-F3). We found the expression of Kchn1, Nron, and Spag17 to be differentially hydroxymethylated and upregulated in the F1 exposed to HDM both in early life and in adulthood when compared to F1 mice exposed solely in adulthood. Kcnh1 remained upregulated in the F2 and F3 from the maternal HDM (F0) exposure lineage, when compared to F1 mice exposed solely in adulthood. In summary, we demonstrated that maternal HDM exposure in early life can alter the gene expression and phenotype of offspring upon adult HDM exposure, resulting in more severe disease. These effects persist at least two generations past the initial insult, transmitted along the paternal line.

Effect of environmental exposures on allergen sensitization and the development of childhood allergic diseases: A large-scale population-based study

Background

Changing environmental factors are likely responsible for the rising prevalence of allergic diseases in children. However, whether environmental exposures induce allergen sensitizations, and which allergen sensitization is related to the development of allergic diseases, is not clear. The study is aimed to investigate the association between environmental exposure, allergen sensitization, and the development of allergic diseases for further preventive intervention.

Methods

We conducted the Taiwan Childhood Environment and Allergic diseases Study (TCEAS) in kindergarten children in Taiwan. Skin prick tests for 6 allergens were performed. Information on the development of allergic diseases and environmental exposure was collected using standardized questionnaires. Multiple logistic regressions were used to estimate the association between environmental factors, allergen sensitization, and the development of allergic diseases.

Results

A total of 3192 children were recruited. 485 (15.2%) children had atopic dermatitis (AD), 1126 (35.3%) had allergic rhinitis (AR), and 552 (17.3%) had asthma. Children with environmental tobacco smoke exposure and fungi on the house wall had a higher risk of asthma, with ORs (95% CIs) of 1.25 (1.03–1.52) and 1.22 (1.01–1.47), respectively. The mite sensitization rate was found to be the highest. Mite sensitization was associated with significant increases in the risks of AD, AR, and asthma, with ORs (95% CIs) of 2.15 (1.53–3.03), 1.94 (1.46–2.58), and 2.31 (1.63–3.29), respectively. Cockroach sensitization also increased the risk of asthma, with an OR (95% CI) of 2.38 (1.01–5.61). Mite sensitization was associated with carpet in the home and fungi on the house wall, and milk sensitization was associated with breastfeeding duration.

Conclusion

Environmental exposures play a role in the development of allergic diseases. Allergen sensitizations were associated with certain environmental exposures. Early environmental interventions are urgently needed to prevent the development of childhood allergic diseases.

Immune Modulation of Allergic Asthma by Early Pharmacological Inhibition of RIP2

Exposure to house dust mite (HDM) is highly associated with the development of allergic asthma. The adaptive immune response to HDM is largely Th2 and Th17 dominant, and a number of innate immune receptors have been identified that recognize HDM to initiate these responses. Nucleotide-binding oligomerization domain-containing protein 2 (NOD2) is a cytosolic sensor of peptidoglycan, which is important for Th2 and Th17 polarization. NOD2 mediates its signaling through its downstream effector kinase, receptor-interacting serine/threonine protein kinase 2 (RIP2). We have previously shown that RIP2 promotes HDM-associated allergic airway inflammation and Th2 and Th17 immunity, acting early in the HDM response and likely within airway epithelial cells. However, the consequences of inhibiting RIP2 during this critical period has not yet been examined. In this study, we pharmacologically inhibited RIP2 activity during the initial exposure to allergen in an acute HDM model of asthma and determined the effect on the subsequent development of allergic airway disease. We show that early inhibition of RIP2 was sufficient to reduce lung histopathology and local airway inflammation while reducing the Th2 immune response. Using a chronic HDM asthma model, we demonstrate that inhibition of RIP2, despite attenuating airway inflammation and airway remodeling, was insufficient to reduce airway hyperresponsiveness. These data demonstrate the potential of pharmacological targeting of this kinase in asthma and support further development and optimization of RIP2-targeted therapies.

Depiction of Major Mite Allergens in Severe Allergic Rhinitis with High Mite Perennial Exposure

Objective

Airway diseases, including allergic rhinitis, are prompted by specific IgE antibodies against airborne allergens and notably those derived from mites. The presented study focused on the specific IgE immediate response to Dermatophagoides pteronyssinus (D. pteronyssinus) mite major allergens and the corresponding pertinence of molecular diagnosis in patients bothered with severe persistent rhinitis.

Methods

Individuals exhibiting confirmed sensitization to D. pteronyssinus along with a clinical diagnosis of coexisting severe allergic rhinitis were included in the study. In vivo investigations encompassed intradermal testing with a battery of standardized allergenic extracts, concurrent with in vitro specific IgE to the crude extract of D. pteronyssinus, and associated individual molecular allergens were assessed.

Results

Fifty-five out of 59 subjects showed serodominant IgE responses to the major allergens Der p 1, Der p 2 and Der p 23. Both Der p 2 and Der p 23 reached a prevalence above 80%, while group 10 allergen tropomyosin was scarcely depicted (<10%) and exclusively present in younger individuals.

Conclusion

The proposed component-resolved diagnosis panel accurately recognized 93.22% of D. pteronyssinus allergic patients. The raised seroprevalence of IgE response to Der p 23 also confirmed this constituent as a major D. pteronyssinus allergen in severe allergic rhinitis. A molecular approach appears to be essential to frame a more precise diagnosis and eventually a personalized immunotherapy regarding this allergic condition.

Group 2 Innate Lymphoid Cells and the House Dust Mite-Induced Asthma Mouse Model

Asthma is an important issue not only in health but also in economics worldwide. Therefore, asthma animal models have been frequently used to understand the pathogenesis of asthma. Recently, in addition to acquired immunity, innate immunity has also been thought to be involved in asthma. Among innate immune cells, group 2 innate lymphoid cells (ILC2s) have been considered to be crucial for eosinophilic airway inflammation by releasing T helper 2 cytokines. Moreover, house dust mites (HDMs) belonging to group 1 act on airway epithelial cells not only as allergens but also as cysteine proteases. The production of interleukin-25 (IL-25), IL-33, and thymic stromal lymphopoietin (TSLP) from airway epithelial cells was induced by the protease activity of HDMs. These cytokines activate ILC2s, and activated ILC2s produce IL-5, IL-9, IL-13, and amphiregulin. Hence, the HDM-induced asthma mouse model greatly contributes to understanding asthma pathogenesis. In this review, we highlight the relationship between ILC2s and the HDM in the asthma mouse model to help researchers and clinicians not only choose a proper asthma mouse model but also to understand the molecular mechanisms underlying HDM-induced asthma.

Prevention of Allergic Asthma with Allergen Avoidance Measures and the Role of Exposome

PURPOSE OF REVIEW

It is well known that combination of sensitization and exposure to inhaled environmental allergens is related to both the development and elicitation of symptoms of asthma and that avoidance of allergens would exert beneficial effects in the prevention and control of the disease. Other important factors include the relevance of other allergens, exposure to sensitizing agents also outside patient's home, exposure to irritants (like chemical air pollutants), and the involvement of the patient with a correct education. It is also likely that clinical phase of allergic airway disease and the degree of airways remodeling represent relevant factors for the clinical outcome of allergen avoidance procedure. We reviewed existing evidence on prevention of asthma through allergen avoidance.

RECENT FINDINGS

The management of respiratory allergy is a complex strategy (including prevention, drugs, immunological, and educational interventions). In addition, it is difficult in real life to distinguish the efficacy of single interventions. However, a combined strategy is likely to produce clinical results. A combined strategy is likely to produce satisfactory management of asthma. Allergens are an important trigger factor for the development of symptoms of respiratory allergy, and avoidance measures are able to reduce allergen levels. It is likely that clinical phase of allergic airway disease and the degree of airways remodeling represents relevant factors for the clinical outcome of allergen avoidance procedures. Considering the management of respiratory allergy is a complex strategy; it is difficult in real life to distinguish the efficacy of single interventions. However, further studies better quantifying the effects of allergens are needed.

House dust mite-specific immunotherapy alters the natural course of atopic march

Allergen immunotherapy (AIT) is an effective treatment for patients with allergic diseases; it has been shown to modify the underlying cause of the disease. The house dust mite (HDM) is a major perennial allergen source and a significant cause of allergic-related diseases such as allergic rhinitis, asthma, and atopic dermatitis. HDM allergen is an important factor in the pathogenesis of allergic diseases. Sensitization to HDM allergen often occurs early in life and appears to play an important role in the progression from allergic rhinitis to asthma in children. The role of HDM AIT results in immunologic tolerance, provides an alternative option for treating HDM allergy through targeting the mechanisms of allergic reaction, and creates a long-term benefit. There are two forms of testing for aeroallergen, either detect by skin testing or by in vitro IgE assays. Both subcutaneous immunotherapy and sublingual immunotherapy are effective in the treatment of allergic diseases. In the future, new forms of allergen extracts can help improve safety and efficacy of AIT. Novel approaches to immunotherapy currently being explored include the use of adjuvants, allergen-derived peptides, modified recombinant allergen vaccines, and gene-specific immunotherapy.

Association between Irritable Bowel Syndrome and Allergic Diseases: To Make a Case for Aeroallergen

Irritable bowel syndrome (IBS) is a functional gastrointestinal disease and the most common cause of prolonged abdominal pain and bowel disturbances in the developed world. While initially thought to be functional or psychosomatic in nature, IBS is now recognized as a heterogeneous group of conditions. A subset of IBS patients and patients with allergic diseases share some characteristic inflammatory features. In fact, atopic children show an increased likelihood of developing IBS as adults. Given these findings, a subset of IBS may be suffering from allergy-related gut diseases. In this review, we present the allergy-related comorbidities of IBS, including genetic, environmental, and immunologic factors. We discuss studies demonstrating an increased sensitization of IBS patients to aeroallergens compared to food allergens. We then postulate potential pathophysiological mechanisms underlying both IBS and aeroallergens in the gut, followed by potential implications in the screening and treatment of allergies in IBS patients.

The Effects of the Environment on Asthma Disease Activity

Asthma is highly prevalent and causes significant morbidity in children. The development of asthma depends on complex relationships between genetic predisposition and environmental modifiers of immune function. The biological and physical environmental factors include aeroallergens, microbiome, endotoxin, genetics, and pollutants. The psychosocial environment encompasses stress, neighborhood safety, housing, and discrimination. They all have been speculated to influence asthma control and the risk of developing asthma. Control of the factors that contribute to or aggravate symptoms, interventions to eliminate allergen exposure, guidelines-based pharmacologic therapy, and education of children and their caregivers are of paramount importance.

Sensitisation to airborne allergens as a risk factor for allergic rhinitis and asthma in the Polish population

Introduction

The patterns of sensitisation to airborne allergens and their association with allergic diseases have been analysed in different geographical regions.

Aim

To analyse the impact of sensitisation to airborne allergens on allergic rhinitis (AR) and asthma in different age groups of the Polish population.

Material and methods

Completed questionnaires of 18,617 subjects (53.8% females), collected within the ECAP, a cross-sectional multicentre study, were analysed. Three groups of respondents were included: 6-7-year-olds (24.2%), 13-14-year-olds (25.4%), 20-44-year-olds (50.4%). The clinical part (an anamnesis, physical examination, spirometry, skin prick tests and an assay of major airborne allergen-specific IgE) was attended by 25.7% of the respondents.

Results

The AR was most strongly related to sensitisation to Dermatophagoides pteronyssinus, with the highest odds ratios of 10 in two younger groups and of 16 for persistent AR in children. It was also the most important risk factor for allergic asthma, with odd ratios from 8.34 in children to 6.40 in adolescents. Sensitisation to grass pollen allergens was a major risk factor for both AR, with odds ratios from 9.16 in adults to 7.87 in adolescents, and asthma, with odds ratios from 6.16 in adolescents to 5.67 in adults.

Conclusions

AR and asthma shared common risk factors, independently of age. Sensitisation to airborne allergens was significantly associated with asthma and, even more strongly, with AR, across all age groups. The AR was the strongest risk factor for allergic asthma in the youngest group. Persistent AR increased asthma risk more than intermittent AR in all age groups.

Indoor air quality in inner-city schools and its associations with building characteristics and environmental factors

Indoor concentrations of fine particulate matter (PM_2.5), nitrogen dioxide (NO₂), and carbon monoxide (CO) were measured across 16 urban public schools in three different seasons. Exceedance of the WHO guidelines for indoor air was observed, mainly for the hourly average NO₂ concentrations. Seasonal variability was statistically significant for indoor NO₂ and CO concentrations, with higher exposures in fall and winter. An extensive list of potential factors at the outdoor environment, school, and room level that may explain the variability in indoor exposure was examined. Factors with significant contributions to indoor exposure were mostly related to the outdoor pollution sources. This is evidenced by the strong associations between indoor concentration of CO and NO₂ and factors including outdoor PM_2.5 and NO₂ concentrations, including length of the nearby roads and the number of nearby industrial facilities. Additionally, we found that poor conditions of the buildings (a prevalent phenomenon in the studied urban area), including physical defects and lack of proper ventilation, contributed to poor air quality in schools. The results suggest that improving building conditions and facilities as well as a consideration of the school surroundings may improve indoor air quality in schools.

Brazilian experience with atopy patch tests for Dermatophagoides pteronyssinus, Dermatophagoides farinae and Blomia tropicalis

Background

The aim of this study was to evaluate the positivity rates of atopy patch tests for Dermatophagoides pteronyssinus, Dermatophagoides farinae and Blomia tropicalis in patients with respiratory diseases such as asthma and allergic rhinitis with or without atopic dermatitis.

Methods

The patients’ clinical histories were collected, and the patients were subjected to skin prick and patch tests with the three different house dust mites on the same day. The patch tests were examined 48 hours later, and then patients were divided into two groups: I- patients with respiratory diseases, such as asthma and/or rhinitis, and atopic dermatitis and II-patients with only respiratory diseases. A total of 74 patients ranging in age from 2 to 60 years were included in this study; 16 patients were included in group I and 58 were included in group II. This study was approved by the human ethics committee of the Faculty of Medical Science and Health SUPREMA (number 2.007.135), and written informed consent was collected from each patient or their parents prior to enrollment.

Results

In the skin prick tests, the most prevalent mite that evoked a reaction was Dermatophagoides pteronyssinus, followed by Dermatophagoides farinae and Blomia tropicalis. Regarding the atopy patch tests, the mite that most frequently induced a positive reaction was Dermatophagoides farinae (78.4%), followed by Dermatophagoides pteronyssinus (77%) and Blomia tropicalis (52.7%). A comparison of the skin prick and atopy patch tests revealed that 53 patients (71.6%) were positive on both tests, and 30 (56.6%) patients were positivite for the same mite. We found six patients (8%) who had a positive clinical history of allergy and only exhibited positivity on the atopy patch test.

Discussion

Most studies have been performed with atopic dermatitis patients, but in this study, most of the patients had respiratory conditions. Blomia tropicalis is a mite that is prevalent in tropical areas, such as Brazil, and only two publications include these three mites, wich are present in Brazil. The APT may produce positive results in concordance with the SPT resuts, but may also be the only positive test ( 8%) as we observed in our study. These results suggest that the mite atopy patch test is relevant and should be considered as an additional test for patients with clinical histories of allergic respiratory disease who have negative prick test results.

Conclusion

The APT should be considered as an additional test when the SPT and specific serum IgE tests are negative in patients with clinical histories of allergies.

Making the Case for "Whole System" Approaches: Integrating Public Health and Housing

Housing conditions have been an enduring focus for public health activity throughout the modern public health era. However, the nature of the housing and health challenge has changed in response to an evolution in the understanding of the diverse factors influencing public health. Today, the traditional public health emphasis on the type and quality of housing merges with other wider determinants of health. These include the neighbourhood, community, and "place" where a house is located, but also the policies which make access to a healthy house possible and affordable for everyone. Encouragingly, these approaches to policy and action on housing have the potential to contribute to the "triple win" of health and well-being, equity, and environmental sustainability. However, more effective housing policies (and in public health in general) that adopt more systemic approaches to addressing the complex interactions between health, housing, and wider environment are needed. This paper illustrates some of the key components of the housing and health challenge in developed countries, and presents a conceptual model to co-ordinate activities that can deliver the "triple win." This is achieved by offering a perspective on how to navigate more effectively, inclusively and across sectors when identifying sustainable housing interventions.

Frontline Science: RIP2 promotes house dust mite-induced allergic airway inflammation

House dust mites (HDMs) are one of the most significant environmental allergens in the establishment of the so-called "Atopic March." It is known that the immune response to HDM is Th2 dominant, but the innate mechanisms leading to HDM-induced type 2 responses are still not completely understood. A number of innate immune receptors have been implicated in the response to HDM including toll-like receptors, C-type lectin receptors, and protease activated receptors. NOD2 is a member of the NOD-like receptor family, which has been reported to be involved in the establishment of type 2 immunity and in blocking respiratory tolerance. NOD2 mediates its effects through its downstream effector kinase, receptor interacting protein (RIP2). It has not been shown if RIP2 is involved in the innate response to HDM and in the resulting generation of type 2 immunity. Furthermore, the role of RIP2 in modulating allergic airway inflammation has been controversial. In this study, we show that RIP2 is activated in airway epithelial cells in response to HDM and is important for the production of CCL2. Using a murine HDM asthma model, we demonstrate that lung pathology, local airway inflammation, inflammatory cytokines, HDM-specific IgG1 antibody production, and HDM-specific Th2 responses are all reduced in RIP2 knockout mice compared to WT animals. These data illustrate that RIP2 can be activated by a relevant allergic stimulus and that such activation can contribute to allergic airway inflammation. These findings also suggest that RIP2 inhibitors might have some efficacy in down-regulating the inflammatory response in type 2 dominated diseases.

Thymus and activation-regulated chemokine (TARC)/CCL17 and IgE are associated with elderly asthmatics

Background

The pathogenesis of asthma, which is an allergic lung disease, is associated with a variety of allergens such as house dust mite, pollen, and mould, IgE containing serum IgE and allergen-specific-IgE, and inflammatory cytokines including thymus and activation-regulated chemokine (TARC)/CCL17. Because aging is an essential factor in the pathogenesis of asthma, we examined biomarkers related to asthmatic subjects depending on age.

Results

Physiological indices such as FEV1(forced expiratory capacity in 1 s), FEV1 (% predicted), and FEV1/FVC(forced vital capacity) (%) in asthmatic subjects were lower than those in normal subjects. Total IgE, Der p1 specific IgE, and Der f1 specific IgE were elevated in serum of asthmatics relative to normal individuals. Regulated on activation, normal T cell expressed and secreted (RANTES)/CCL5 in serum and interleukin 6 (IL-6), interleukin 8 (IL-8), monocyte chemoattractant protein (MCP)-1/CCL2, RANTES, and macrophage inflammatory protein (MIP)-1α/CCL3 in bronchoalveolar lavage fluid (BALF) of asthmatic subjects were higher than in normal individuals. Upon classification of experimental groups depending on age, physiological indices and Der p1-specific IgE (class) were decreased in middle aged adult and elderly adult groups relative to the young adult group. TARC levels in serum were strongly elevated in the elderly adult group relative to the young adult and the middle aged adult groups. TARC in serum was related to total IgE in serum in the elderly adult group.

Conclusions

Taken together, although TARC in serum and BALF is not different between normal and asthmatic individuals, TARC increases in serum of elderly asthmatic subjects. The level of TARC has a positive effect on the level of IgE in the elderly adult group. These findings may help us better understand the relationship of pathogenesis of allergic diseases and aging.

Electronic supplementary material

The online version of this article (10.1186/s12979-018-0118-7) contains supplementary material, which is available to authorized users.

House Dust Mite Sublingual Immunotherapy for Pediatric Patients With Allergic Asthma

OBJECTIVE

To review the published literature evaluating administration of house dust mite (HDM) sublingual immunotherapy (SLIT) in pediatric patients with allergic asthma.

DATA SOURCES

PubMed database search (1966 to November 2017) using the search terms allergy, allergic rhinitis, asthma, allergic asthma, house dust mite, allergen immunotherapy, subcutaneous immunotherapy, sublingual immunotherapy, MK-8237, children, and pediatric. Package labeling and references from identified articles were also reviewed.

STUDY SELECTION AND DATA EXTRACTION

Studies published in English evaluating the efficacy of HDM SLIT in children <18 years of age were included.

DATA SYNTHESIS

Patients with allergic asthma who fail to improve with pharmacotherapy may require disease-modifying, HDM-specific immunotherapy. Acceptance of subcutaneous immunotherapy (SCIT) in the pediatric population is limited by the need for weekly injections and the risk of systemic adverse effects. Trials in pediatric patients with allergic rhinitis and asthma monosensitized to HDM demonstrated mixed results, likely because of variability in methodologies. SLIT reduced asthma symptoms in 8 placebo-controlled studies; however, asthma medication use was reduced in just 4 trials. Compared with pharmacotherapy alone, SLIT and SCIT decreased asthma symptom scores similarly for up to 3 years. Sequential SCIT/SLIT decreased both asthma symptoms and medication scores and was more effective than SLIT alone.

CONCLUSIONS

Sublingual HDM immunotherapy reduces symptom scores in pediatric patients with allergic asthma but may be slower in onset and less effective than SCIT in reducing asthma medication use.

The role of the indoor environment: Residential determinants of allergy, asthma and pulmonary function in children from a US-Mexico border community

The El Paso Children's Health Study examined environmental risk factors for allergy and asthma among fourth and fifth grade schoolchildren living in a major United States-Mexico border city. Complete questionnaire information was available for 5210 children, while adequate pulmonary function data were available for a subset of 1874. Herein we studied indoor environmental health risk factors for allergy and asthma. Several indoor environmental risk factors were associated with allergy and asthma. In particular, we found that ant and spider pest problems, pet dogs, fireplace heat, central air conditioning, humidifier use, and cooking with gas stoves were positively associated with both allergy and asthma prevalence. With regards to asthma severity, our analysis indicated that exposure to pet dogs increased monotonically with increasing asthma severity while the lack of any heat source and gas stove use for cooking decreased monotonically with increasing asthma severity. Lung function also decreased among children who lived in homes with reported cockroach pest problem in the past year without concurrent use of pesticides. These effects on pulmonary function were present even after excluding children with a current physician's diagnosis of asthma. Clinicians and public health professionals may need to look closely at the contribution of these indoor risk factors on pulmonary health and quality of life among susceptible populations.

The effects of early life adversity on the immune system

Early life adversity (ELA) is associated with a higher risk for diseases in adulthood. Although the pathophysiological effects of ELA are varied, there may be a unifying role for the immune system in all of the long-term pathologies such as chronic inflammatory disorders (autoimmune diseases, allergy, and asthma). Recently, significant efforts have been made to elucidate the long-term effects ELA has on immune function, as well as the mechanisms underlying these immune changes. In this review, we focus on data from human studies investigating immune parameters in relation to post-natal adverse experiences. We describe the current understanding of the 'ELA immune phenotype', characterized by inflammation, impairment of the cellular immune system, and immunosenescence. However, at present, data addressing specific immune functions are limited and there is a need for high-quality, well powered, longitudinal studies to unravel cause from effect. Besides the immune system, also the stress system and health behaviors are altered in ELA. We discuss probable underlying mechanisms based on epigenetic programming that could explain the ELA immune phenotype and whether this is a direct effect of immune programming or an indirect consequence of changes in behavior or stress reactivity. Understanding the underlying mechanisms will help define effective strategies to prevent or counteract negative ELA-associated outcomes.

Different clinical effect of several types of airborne allergens on the severity of bronchial hyperreactivity

BACKGROUND

Atopic sensitization belongs to the most common risk factors for bronchial asthma. However, in clinical practice, it is not clear whether sensitization against pollen and perennial allergens is differently associated with the severity of bronchial hyperresponsiveness (BHR).

AIM

To find out whether patients sensitized to perennial allergens differ in severity of bronchial hyperresponsiveness from patients sensitized to pollen allergens.

METHODS

The study includes 109 patients. Based on the results of skin prick tests, patients were divided into three groups: sensitivity to pollen allergens - group A; sensitivity to perennial allergens - group B; sensitivity to both pollen and perennial allergens - group C. Based on the histamine bronchoprovocation test, we compared the values of histamine provocative concentration causing a 20% drop in FEV₁ (PC₂₀) among particular groups of patients. Mild bronchial hyperresponsiveness was determined if the value of PC₂₀ was >4 mg/ml, while if the value of PC₂₀ was <4 mg/ml, the bronchial hyperresponsiveness was considered as moderate/severe.

RESULTS

A statistically significant difference was found in the degrees of bronchial hyperresponsiveness between the three groups of patients, namely, group A with the patients sensitized only to the pollen allergens, group B comprising patients sensitized to the perennial allergens only, and group C, involving patients sensitized to the combination of both pollen and perennial allergens. The PC₂₀ values were higher among the patients from the group A (7.46 mg/ml) compared to group B (4.25 mg/ml) and C (4.52 mg/ml). The odds ratio for moderate/severe BHR was 5.21 and 5.04 in group B and group C, respectively.

CONCLUSION

Severity of bronchial hyperresponsiveness shows differences according to sensitization to particular allergens. Perennial allergens are more often associated with serious forms of bronchial hyperresponsiveness which also have an impact on the severity and prognosis of bronchial asthma.

Environmental Determinants of Bronchial Asthma among Saudi School Children in Southwestern Saudi Arabia

The aim here was to study the possible environmental and dietary determinants of asthma among school-aged children in Southwestern Saudi Arabia. In a cross-sectional study on a representative sample in Najran in Southwestern Saudi Arabia using an Arabic version of the modified ISAAC Phase III, parent-administered questionnaire data were collected. Skin prick tests (SPTs) were performed. The study included 1700 school children, out of them 468 (27.5%) were diagnosed with, cases of bronchial asthma and 20.8% (353) reported a 12-month nocturnal cough (as a proxy of severe asthma). In multivariable analysis, the study identified the following risk factors for having asthma or severe asthma: having dogs in the house, being male, being exposed to dense truck traffic on the street, using wood as a cooking fuel, conducting vigorous exercise, consuming eggs, consuming vegetables, having an allergic sensitization to dog hair, and being exposed to Cladosporium, pigweed, and Bermuda grass. On the other hand, the following food stuffs were found to be protective: seafood, fruit, and dairy products. Comprehensive school educational programs for both children and their parents should be adopted to prevent the use of wood in cooking and heating, to ensure that house pets are properly cared for, and to encourage proper dietary habits. Physicians should be informed of the patterns of allergens in order to improve asthma diagnosis and management.

Respiratory Diseases in University Students Associated with Exposure to Residential Dampness or Mold

University students are frequently exposed to residential dampness or mold (i.e., visible mold, mold odor, dampness, or water leaks), a well-known contributor to asthma, allergic rhinitis, and respiratory infections. This study aims to: (a) describe the prevalence of these respiratory diseases among university students; and (b) examine the independent contribution of residential dampness or mold to these diseases. An online survey was conducted in March 2014 among the 26,676 students registered at the Université de Sherbrooke (Quebec, Canada). Validated questions and scores were used to assess self-reported respiratory diseases (i.e., asthma-like symptoms, allergic rhinitis, and respiratory infections), residential dampness or mold, and covariates (e.g., student characteristics). Using logistic regressions, the crude and adjusted odd ratios between residential dampness or mold and self-reported respiratory diseases were examined. Results from the participating students (n = 2097; response rate: 8.1%) showed high prevalence of allergic rhinitis (32.6%; 95% CI: 30.6–34.7), asthma-like symptoms (24.0%; 95% CI: 22.1–25.8) and respiratory infections (19.4%; 95% CI: 17.7–21.2). After adjustment, exposure to residential dampness or mold was associated with allergic rhinitis (OR: 1.25; 95% CI: 1.01–1.55) and asthma-like symptoms (OR: 1.70; 95% CI: 1.37–2.11), but not with respiratory infections (OR: 1.07; 95% CI: 0.85–1.36). Among symptomatic students, this exposure was also associated with uncontrolled and burdensome respiratory symptoms (p < 0.01). University students report a high prevalence of allergic rhinitis, asthma-like symptoms and respiratory infections. A common indoor hazard, residential dampness or mold, may play a role in increasing atopic respiratory diseases and their suboptimal control in young adults. These results emphasize the importance for public health organizations to tackle poor housing conditions, especially amongst university students who should be considered “at-risk”.

Relationships among aeroallergen sensitization, peripheral blood eosinophils, and periostin in pediatric asthma development

BACKGROUND

Biomarkers, preferably noninvasive, that predict asthma inception in children are lacking.

OBJECTIVE

Little is known about biomarkers of type 2 inflammation in early life in relation to asthma inception. We evaluated aeroallergen sensitization, peripheral blood eosinophils, and serum periostin as potential biomarkers of asthma in children.

METHODS

Children enrolled in the Childhood Origins of ASThma study were followed prospectively from birth. Blood samples were collected at ages 2, 4, 6, and 11 years, and serum-specific IgE levels, blood eosionophil counts, and periostin levels were measured in 244 children. Relationships among these biomarkers, age, and asthma were assessed.

RESULTS

Serum periostin levels were approximately 2- to 3-fold higher in children than previously observed adult levels. Levels were highest at 2 years (145 ng/mL), and did not change significantly between 4 and 11 years (128 and 130 ng/mL). Age 2 year periostin level of 150 ng/mL or more predicted asthma at age 6 years (odds ratio [OR], 2.3; 95% CI, 1.3-4.4). Eosinophil count of 300 cells/μL or more and aeroallergen sensitization at age 2 years were each associated with increased risk of asthma at age 6 years (OR, 3.1; 95% CI, 1.7-6.0 and OR, 3.3; 95% CI, 1.7-6.3). Children with any 2 of the biomarkers had a significantly increased risk of developing asthma by school age (≥2 biomarkers vs none: OR, 6.6; 95% CI, 2.7-16.0).

CONCLUSIONS

Serum periostin levels are significantly higher in children than in adults, likely due to bone turnover, which impairs clinical utility in children. Early life aeroallergen sensitization and elevated blood eosinophils are robust predictors of asthma development. Children with evidence of activation of multiple pathways of type 2 inflammation in early life are at greatest risk for asthma development.

Variable risk of atopic disease due to indoor fungal exposure in NHANES 2005-2006

BACKGROUND

Exposure to damp indoor environments is associated with increased risk of eczema, allergy and asthma. The role of dampness-related exposures and risk of allergic diseases are yet to be fully explored in the US population.

OBJECTIVE

We assess whether exposure to fungi, house dust mites and endotoxin increases the risk of eczema, allergy and asthma in children and adults participating in NHANES 2005-2006.

METHODS

A total of 8412 participants (2849 were children aged between 6 and 17 years) were recruited in the 2005-2006 survey. We used multiple logistic regression to investigate whether mildew/musty odour and increased concentrations of Alternaria alternata allergen, Aspergillus fumigatus antigens, house dust mite and endotoxin antigens increase the risk of eczema, allergy and asthma. We stratified models by total IgE < 170 and ≥ 170 KU/L to assess allergic and non-allergic asthma outcomes. Exposure to multiple biological agents and risk of reporting eczema, allergy and asthma were also investigated.

RESULTS

Reporting of a mildew/musty odour was associated with increased risk of childhood asthma (OR 1.60; 95% CI 1.17-2.19), and adult eczema, allergy and asthma (OR 1.92; 95% CI 1.39-2.63, OR 1.59 95% CI 1.26-2.02 and OR 1.61 95% CI 1.00-2.57, respectively). Risk of asthma was associated with total IgE ≥ 170 KU/L in children (OR 1.81; 95% CI 1.01-3.25) and total IgE < 170 KU/L in adults (OR 1.91; 95% CI 1.07-3.42). Children and adults exposed to more than eight biological agents present in the home were at reduced risk of eczema (OR 0.17; 95% CI 0.04-0.77) and asthma (OR 0.49; 95% CI 0.25-0.97), respectively.

CONCLUSION

Exposure to a mildew/musty odour, as a proxy for exposure to fungus, was implicated in an increased risk of atopic diseases. Sensitisation may play a different role in children and adults, and exposure to multiple allergens may reduce the risk of atopic disease.

Efficacy and safety of sublingual tablets of house dust mite allergen extracts: Results of a dose-ranging study in an environmental exposure chamber

BACKGROUND

In a natural field study, sublingual tablets of house dust mite (HDM) allergen extracts (STG320) were efficacious in treating HDM-associated allergic rhinitis.

OBJECTIVES

We sought to assess the efficacy and safety of 3 doses of STG320 in an environmental exposure chamber.

METHODS

In this randomized, double-blind study, adults with HDM-associated allergic rhinitis were given a daily sublingual tablet containing placebo or STG320 at a dose of 500IR, 300IR, or 100IR (IR, index of reactivity) for 6 months. Participants recorded their rhinitis symptoms during 4-hour HDM EEC challenges at randomization and months 1, 2, 4, and 6. The primary efficacy end point was the change from baseline to end of treatment in the area under the curve of the rhinitis total symptom score (ChBLAUCRTSS 0-4h). Differences from the placebo group were analyzed by analysis of covariance. Adverse events (AEs) and routine safety parameters were recorded.

RESULTS

A total of 355 subjects were randomized to 1 of 4 groups: 500IR (n = 93), 300IR (n = 86), 100IR (n = 89), or placebo (n = 87). The least squares mean differences from placebo in ChBLAUCRTSS 0-4h for the 500IR, 300IR, and 100IR groups indicated a dose-dependent effect, with reductions in symptom scores of 33%, 29%, and 20%, respectively. The most frequent AEs were throat irritation and oral pruritus. There were no reports of anaphylaxis or reports consistent with severe laryngopharyngeal disorders and no use of epinephrine. AEs leading to premature discontinuations were more common in the 500IR group.

CONCLUSIONS

A dose-dependent effect of sublingual HDM immunotherapy was demonstrated in this environmental exposure chamber study, supporting further development of this treatment.

Aggravation of Allergic Airway Inflammation by Cigarette Smoke in Mice Is CD44-Dependent

Background

Although epidemiological studies reveal that cigarette smoke (CS) facilitates the development and exacerbation of allergic asthma, these studies offer limited information on the mechanisms involved. The transmembrane glycoprotein CD44 is involved in cell adhesion and acts as a receptor for hyaluronic acid and osteopontin. We aimed to investigate the role of CD44 in a murine model of CS-facilitated allergic airway inflammation.

Methods

Wild type (WT) and CD44 knock-out (KO) mice were exposed simultaneously to house dust mite (HDM) extract and CS. Inflammatory cells, hyaluronic acid (HA) and osteopontin (OPN) levels were measured in bronchoalveolar lavage fluid (BALF). Proinflammatory mediators, goblet cell metaplasia and peribronchial eosinophilia were assessed in lung tissue. T-helper (Th) 1, Th2 and Th17 cytokine production was evaluated in mediastinal lymph node cultures.

Results

In WT mice, combined HDM/CS exposure increased the number of inflammatory cells and the levels of HA and OPN in BALF and Th2 cytokine production in mediastinal lymph nodes compared to control groups exposed to phosphate buffered saline (PBS)/CS, HDM/Air or PBS/Air. Furthermore, HDM/CS exposure significantly increased goblet cell metaplasia, peribronchial eosinophilia and inflammatory mediators in the lung. CD44 KO mice exposed to HDM/CS had significantly fewer inflammatory cells in BALF, an attenuated Th2 cytokine production, as well as decreased goblet cells and peribronchial eosinophils compared to WT mice. In contrast, the levels of inflammatory mediators were similar or higher than in WT mice.

Conclusion

We demonstrate for the first time that the aggravation of pulmonary inflammation upon combined exposure to allergen and an environmental pollutant is CD44-dependent. Data from this murine model of concomitant exposure to CS and HDM might be of importance for smoking allergic asthmatics.

Comparison of Living and Bedrooms in Terms of House Dust Mites in the Province of Erzincan, Turkey

The most important factors in development of symptoms such as allergic asthma, rhinitis, conjunctivitis, and dermatitis in atopic persons are the allergens of house dust mites. The objective of this study was to compare living rooms and bedrooms, and woolen and spring mattresses in terms of the number and species of mites in houses in the province of Erzincan, Turkey. In total, 74 dust samples were collected from living rooms and bedrooms of 37 randomly selected houses from various districts of the city. All examined houses were positive for house dust mites. In total, 5,210 mites were isolated, 1,058 from the living rooms and 4,152 from the bedrooms, and the differences were statistically significant (P < 0.05). Of 4,152 mites detected in bedrooms, 1,330 (32%) were isolated from 31 spring mattresses and 2,822 (68%) from 6 woolen mattresses (P < 0.001). The study identified 14 families, 17 genera, and 16 species belonging to Astigmata, Prostigmata, and Oribatida. Of these, Dermatophagoides pteronyssinus (Trouessart) was the dominant species: living rooms, 63.3%; bedrooms, 74.4%; woolen mattresses, 84.6%; and spring mattresses, 52.8%. This was followed by Lepidoglyphus destructor (Schrank) (9.8%), Dermatophagoides farinae Hughes (5.1%), Tyrophagus putrescentiae (Schrank) (4.3%), and Acarus siro L. (2.5%) in living rooms; L. destructor (11.2%), Euroglyphus maynei (Cooreman) (4.2%), D. farinae (3.8%), and T. putrescentiae (1.0%) in bedrooms; L. destructor (11.8%), D. farinae (2.1%), E. maynei (0.3%), and T. putrescentiae (0.2%) in woolen mattresses; and E. maynei (12.5%), L. destructor (9.9%), D. farinae (7.5%), and T. putrescentiae (2.7%) in spring mattresses.

Identifying risk factors for exposure to culturable allergenic moulds in energy efficient homes by using highly specific monoclonal antibodies

The aim of this study was to determine the accuracy of monoclonal antibodies (mAbs) in identifying culturable allergenic fungi present in visible mould growth in energy efficient homes, and to identify risk factors for exposure to these known allergenic fungi. Swabs were taken from fungal contaminated surfaces and culturable yeasts and moulds isolated by using mycological culture. Soluble antigens from cultures were tested by ELISA using mAbs specific to the culturable allergenic fungi Aspergillus and Penicillium spp., Ulocladium, Alternaria, and Epicoccum spp., Cladosporium spp., Fusarium spp., and Trichoderma spp. Diagnostic accuracies of the ELISA tests were determined by sequencing of the internally transcribed spacer 1 (ITS1)-5.8S-ITS2-encoding regions of recovered fungi following ELISA. There was 100% concordance between the two methods, with ELISAs providing genus-level identity and ITS sequencing providing species-level identities (210 out of 210 tested). Species of Aspergillus/Penicillium, Cladosporium, Ulocladium/Alternaria/Epicoccum, Fusarium and Trichoderma were detected in 82% of the samples. The presence of condensation was associated with an increased risk of surfaces being contaminated by Aspergillus/Penicillium spp. and Cladosporium spp., whereas moisture within the building fabric (water ingress/rising damp) was only associated with increased risk of Aspergillus/Penicillium spp. Property type and energy efficiency levels were found to moderate the risk of indoor surfaces becoming contaminated with Aspergillus/Penicillium and Cladosporium which in turn was modified by the presence of condensation, water ingress and rising damp, consistent with previous literature.

Development of recombinant stable house dust mite allergen Der p 3 molecules for component-resolved diagnosis and specific immunotherapy

BACKGROUND

The allergen Der p 3 is underrepresented in house dust mite (HDM) extracts probably due to autolysis. Recombinant stable molecule of the allergen is thus needed to improve the diagnosis of allergy and the safety and efficacy of immunotherapy.

OBJECTIVE

The current study reports the immunological characterization of two recombinant molecules of the HDM allergen Der p 3 as useful tools for diagnosis and immunotherapy.

METHODS

Recombinant mature (rDer p 3) and immature (proDer p 3) Der p 3 and their corresponding S196A mutants were produced in Pichia pastoris and purified. The stability, IgE-binding capacity and allergenicity of the different proteins were analysed and compared with those of the major mite allergen Der p 1 used as a reference. Additionally, the immunogenicity of the different allergens was evaluated in a murine model of Der p 3 sensitization.

RESULTS

Compared to the IgE reactivity to recombinant and natural Der p 3 (nDer p 3), the mean IgE binding of patient's sera to rDer p 3-S196A (50%) was higher. The poorly binding to nDer p 3 or rDer p 3 was due to autolysis of the allergen. Contrary to Der p 3, proDer p 3 displayed very weak IgE reactivity, as measured by sandwich ELISA and competitive inhibition, rat basophil leukaemia degranulation and human basophil activation assays. Moreover, proDer p 3 induced a TH 1-biased immune response that prevented allergic response in mice but retained Der p 3-specific T-cell reactivity.

CONCLUSION

rDer p 3-S196A should be used for the diagnosis of HDM allergy elicited by Der p 3, and proDer p 3 may represent a hypoallergen of Der p 3.

Concentration and determinants of molds and allergens in indoor air and house dust of French dwellings

Molds and allergens are common indoor biocontaminants. The aims of this study were to assess the concentrations of common molds in indoor air and floor dust and the concentrations of house dust mite, cat and dog allergens in mattress dust in French dwellings, and to assess predictors of these concentrations. A sample of 150 houses in Brittany (western France) was investigated. Airborne Cladosporium and Penicillium were detected in more than 90% of the dwellings, Aspergillus in 46% and Alternaria in only 6% of the housings. Regarding floor dust samples, Cladosporium and Penicillium were detected in 92 and 80% of the housings respectively, Aspergillus in 49% and Alternaria in 14%. House dust mite allergens Der p1 and Der f1 were detected in 90% and 77% of the mattress dust samples respectively and Can f1 and Fel d1 in 37% and 89% of the homes. Airborne and dustborne mold concentrations, although not statistically correlated (except for Aspergillus) shared most of their predictors. Multivariate linear models for mold levels, explaining up to 62% of the variability, showed an influence of the season, of the age of the dwelling, of aeration habits, presence of pets, smoking, signals of dampness, temperature and relative humidity. Allergens in the dust of the mattress were strongly related to the presence of pets and cleaning practices of bedsheets, these factors accounting for 60% of the variability. This study highlights ubiquitous contamination by molds and underlines complex interaction between outdoor and indoor sources and factors.

Pim1 kinase activity preserves airway epithelial integrity upon house dust mite exposure

Most patients with allergic asthma are sensitized to house dust mite (HDM). The allergenicity of HDM largely depends on disruption of the integrity and proinflammatory activation of the airway epithelium. In this study, we hypothesized that Pim1 kinase activity attenuates HDM-induced asthma by preserving airway epithelial integrity. The effects of Pim1 kinase activity on barrier function and release of the proinflammatory mediators IL-1α and CCL20 were studied in vitro in 16HBE and primary bronchial epithelial cells (PBECs). Pim1-proficient and -deficient mice were exposed to a HDM-driven model of allergic asthma, and airway hyperresponsiveness (AHR) was measured upon methacholine challenge. Airway inflammation and proinflammatory mediators in lung tissue and BAL fluid were determined. We observed that inhibition of Pim1 kinase prolongs the HDM-induced loss of barrier function in 16HBE cells and sensitizes PBECs to HDM-induced barrier dysfunction. Additionally, inhibition of Pim1 kinase increased the HDM-induced proinflammatory activity of 16HBE cells as measured by IL-1α secretion. In line herewith, HDM exposure induced an enhanced production of the proinflammatory chemokines CCL17 and CCL20 in Pim1-deficient mice compared with wild-type controls. While we observed a marked increase in eosinophilic and neutrophilic granulocytes as well as mucus cell metaplasia and AHR to methacholine in mice exposed to HDM, these parameters were independent of Pim1 kinase activity. In contrast, levels of the Th2-cytokines IL-5 and IL-10 were significantly augmented in HDM-treated Pim1-deficient mice. Taken together, our study shows that Pim1 kinase activity maintains airway epithelial integrity and protects against HDM-induced proinflammatory activation of the airway epithelium.

Apoptosis and engulfment by bronchial epithelial cells. Implications for allergic airway inflammation

Insult or injury to the lung epithelial cells from pathogens, pollutants, and allergens can initiate the process of apoptotic cell death. Although "Creola bodies," which are clusters of uncleared, apoptotic, epithelial cells, have been seen in the sputum of patients with asthma, the clearance of these dying epithelial cells and the consequence of failed clearance in the airway have not been directly addressed. We have observed that bronchial epithelial cells efficiently engulf their apoptotic neighbors and produce antiinflammatory cytokines when engulfing apoptotic cells. Furthermore, when the phagocytic capacity of bronchial epithelial cells was impaired, mice developed severe, IL-33-dependent, allergic airway inflammation. This inflammation could be ameliorated by exogenous administration of the antiinflammatory cytokine IL-10. Our data suggest that the process of apoptotic cell engulfment is a mechanism by which bronchial epithelial cells regulate the inflammatory environment within the lung. Collectively, these studies suggest that impaired engulfment pathways in airway epithelial cells can contribute to allergic airway inflammation and that targeting these pathways may be of benefit in human airway inflammation.

Perennial aeroallergens sensitisation and risk of asthma in African children and adolescents: a case-control study

OBJECTIVES

The distribution and impact of various aeroallergens on asthma occurrence vary across regions. We investigated the association between sensitisation to perennial aeroallergens and asthma risk in children and adolescents in Yaounde, Cameroon.

METHODS

This was a case-control study involving children and adolescents with asthma (cases) vs. non-allergic counterparts (controls). Children/adolescents with doctor-diagnosed asthma were included over a period of 30 months, and controls were selected from the community through random sampling. Logistic regression models were used to relate perennial aeroallergens sensitisation with asthma.

RESULTS

The asthma and control groups included, respectively, 151 and 372 participants, with no sex ratio difference. The mean age (standard deviation) was 11.9 (4.4) years in cases and 11.3 (3.7) years in controls. The prevalence of sensitisation to any aeroallergen (cases vs. controls) was 76.8% (116/151) and 32.3% (120/372), p < 0.001. Sensitisation to mites was found in 104 (68.9%) cases vs. 56 (15.1%) controls, p < 0.001. In multivariable analysis, sensitisation to Alternaria alternata, Blattella germanica and dander (cat and dog) was not associated with asthma. However, sensitisation to mites was significantly associated with asthma. Odds ratios (95% CI) for sensitisation to Dermatophagoides pteronyssinus, Dermatophagoides farinae and Blomia tropicalis in relation with asthma were 7.28 (3.75-14.15), 2.65 (1.27-5.45) and 3.23 (1.68-6.21), respectively.

CONCLUSIONS

Sensitisation to mites was the main perennial allergenic factor associated with asthma in children and adolescents in this setting. This has application for the selection of patients with asthma who could benefit from the control of exposure to mites and specific immunotherapy.

An Allergic Lung Microenvironment Suppresses Carbon Nanotube-Induced Inflammasome Activation via STAT6-Dependent Inhibition of Caspase-1

Background

Multi-walled carbon nanotubes (MWCNTs) represent a human health risk as mice exposed by inhalation display pulmonary fibrosis. Production of IL-1β via inflammasome activation is a mechanism of MWCNT-induced acute inflammation and has been implicated in chronic fibrogenesis. Mice sensitized to allergens have elevated T-helper 2 (Th2) cytokines, IL-4 and IL-13, and are susceptible to MWCNT-induced airway fibrosis. We postulated that Th2 cytokines would modulate MWCNT-induced inflammasome activation and IL-1β release in vitro and in vivo during allergic inflammation.

Methods

THP-1 macrophages were primed with LPS, exposed to MWCNTs and/or IL-4 or IL-13 for 24 hours, and analyzed for indicators of inflammasome activation. C57BL6 mice were sensitized to house dust mite (HDM) allergen and MWCNTs were delivered to the lungs by oropharyngeal aspiration. Mice were euthanized 1 or 21 days post-MWCNT exposure and evaluated for lung inflammasome components and allergic inflammatory responses.

Results

Priming of THP-1 macrophages with LPS increased pro-IL-1β and subsequent exposure to MWCNTs induced IL-1β secretion. IL-4 or IL-13 decreased MWCNT-induced IL-1β secretion by THP-1 cells and reduced pro-caspase-1 but not pro-IL-1β. Treatment of THP-1 cells with STAT6 inhibitors, either Leflunomide or JAK I inhibitor, blocked suppression of caspase activity by IL-4 and IL-13. In vivo, MWCNTs alone caused neutrophilic infiltration into the lungs of mice 1 day post-exposure and increased IL-1β in bronchoalveolar lavage fluid (BALF) and pro-caspase-1 immuno-staining in macrophages and airway epithelium. HDM sensitization alone caused eosinophilic inflammation with increased IL-13. MWCNT exposure after HDM sensitization increased total cell numbers in BALF, but decreased numbers of neutrophils and IL-1β in BALF as well as reduced pro-caspase-1 in lung tissue. Despite reduced IL-1β mice exposed to MWCNTs after HDM developed more severe airway fibrosis by 21 days and had increased pro-fibrogenic cytokine mRNAs.

Conclusions

These data indicate that Th2 cytokines suppress MWCNT-induced inflammasome activation via STAT6-dependent down-regulation of pro-caspase-1 and suggest that suppression of inflammasome activation and IL-1β by an allergic lung microenvironment is a mechanism through which MWCNTs exacerbate allergen-induced airway fibrosis.

House Dust Mite Allergen Regulates Constitutive Apoptosis of Normal and Asthmatic Neutrophils via Toll-Like Receptor 4

House dust mites (HDMs) induce allergic diseases such as asthma. Neutrophil apoptosis is an important process of innate immunity, and its dysregulation is associated with asthma. In this study, we examined the effects of HDM on constitutive apoptosis of normal and asthmatic neutrophils. Extract of Dermatophagoides pteronissinus (DP) inhibited neutrophil apoptosis, but Dermatophagoides farinae extract had no effect. Anti-apoptotic signaling mediated by DP involves in TLR4, Lyn, PI3K, Akt, ERK, and NF-κB in normal neutrophils. DP delayed cleavage of procaspase 9 and procaspase 3 and the decrease in Mcl-1 expression. Supernatant collected from DP-treated normal neutrophils inhibited the constitutive apoptosis of normal neutrophils, and S100A8 and S100A9 were identified as anti-apoptotic proteins in the supernatant. S100A8 and S100A9 transduced the anti-apoptotic signal via TLR4, Lyn, PI3K, Akt, ERK, and NF-κB. DP also suppressed asthmatic neutrophil apoptosis and induced secretion of S100A8 and S100A9, which delayed the constitutive apoptosis. The anti-apoptotic effects of DP, S100A8 and S100A9 in asthmatic neutrophils are associated with TLR4, Lyn, PI3K, Akt, ERK, and NF-κB. The concentrations of S100A8 and S100A9 were significantly elevated in asthmatic bronchoalveolar lavage fluid (BALF) when compared to normal BALF (p<0.01), but not in serum. S100A8 concentration in BALF was positively correlated with the number of BALF neutrophils and negatively correlated with FEV1(%). These findings improve our understanding of the role of HDM in regulation of neutrophil apoptosis in normal individuals and asthmatics and will enable elucidation of asthma pathogenesis.