House Dust Mite Interactions with Airway Epithelium: Role in Allergic Airway Inflammation

German cockroach extract prevents IL-13-induced CCL26 expression in airway epithelial cells through IL-13 degradation

Inhaled aeroallergens can directly activate airway epithelial cells (AECs). Exposure to cockroach allergens is a strong risk factor for asthma. Cockroach allergens mediate some of their effects through their serine protease activity; protease activity is also a major contributor to allergenicity. The Th2 cytokine interleukin-13 (IL-13) induces upregulation of the eosinophil chemotactic factor CCL26. CCL26 induces eosinophil migration in allergic inflammation. In this work, we studied the effect of cockroach proteases on IL-13-induced effects. Immersed cultures of the human bronchial epithelial cell line BEAS-2B and air-liquid interface (ALI) cultures of primary normal human bronchial epithelial (NHBE) cells were stimulated with IL-13, Blattella Germanica cockroach extract (CE), or both. IL-13-induced genes were analyzed with qRT-PCR. IL-13 induced upregulation of CCL26, periostin, and IL-13Rα2 in bronchial epithelial cells which were decreased by CE. CE was heat-inactivated (HICE) or pre-incubated with protease inhibitors. HICE and CE preincubated with serine protease inhibitors did not prevent IL-13-induced CCL26 upregulation. CE-degraded IL-13 and specific cleavage sites were identified. CE also decreased IL-4-induced CCL26 upregulation and degraded IL-4. Other serine proteases such as bovine trypsin and house dust mite (HDM) serine proteases did not have the same effects on IL-13-induced CCL26. We conclude that CE serine proteases antagonize IL-13-induced effects in AECs, and this CE effect is mediated primarily through proteolytic cleavage of IL-13. IL-13 cleavage by cockroach serine proteases may modulate CCL26-mediated effects in allergic airway inflammation by interfering directly with the pro-inflammatory effects of IL-13 in vivo.

Clinical benefits with 300 IR HDM SLIT tablet in Europeans with house dust mite allergic rhinitis: Post hoc analysis of a large phase 3 trial

Background

House dust mite (HDM)-induced allergic rhinitis (AR) is a major cause of allergic respiratory disease. The efficacy and safety of the 300 IR HDM sublingual immunotherapy (SLIT) tablet in patients with moderate-to-severe HDM-AR was confirmed in a large, international, phase 3 randomized controlled trials (RCTs). Here, we analyzed the results in the European population.

Methods

Data from 91 European centers that participated in the international, double-blind, RCT (EudraCT 2014-004223-46, NCT02443805) with the 300 IR HDM SLIT tablet versus placebo over 12 months were analyzed post hoc. The treatment effect in European adults and adolescents was notably assessed through the European Academy of Allergy and Clinical Immunology (EAACI)-recommended combined symptom and medication score (CSMS0-6, pre-defined endpoint) and the total combined rhinitis score (TCRS0-24, post hoc endpoint, also balanced) during the primary evaluation period (4 weeks at the end of treatment period) using analysis of covariance (ANCOVA).

Results

There were 818 patients who comprised the modified full analysis set in Europe. Over the primary period, the differences in CSMS0-6 and TCRS0-24 between the 300 IR and placebo groups were statistically significant (p < 0.0001): -0.32 (95%CI [-0.46; -0.17]) and -1.28 (95%CI [-1.63; -0.94]), respectively, with relative differences of -20.9% and -21.2%. All post hoc and the rhinoconjunctivitis quality of life endpoints were significantly improved with 300 IR versus placebo. The 300 IR HDM tablet was generally well tolerated.

Conclusion

This RCT sub-analysis confirmed the 300 IR HDM SLIT tablet is an effective and safe treatment for European adults and adolescents with HDM-AR with clinically meaningful benefits from the patients' perspective.

Trial registration

NCT02443805. Registered on April 29, 2015./EudraCT 2014-004223-46. Registered on September 16, 2015.

Dynamic expression of mucins and the genes controlling mucin-type O-glycosylation within the mouse respiratory system

The COVID-19 global pandemic has underscored the need to understand how viruses and other pathogens are able to infect and replicate within the respiratory system. Recent studies have highlighted the role of highly O-glycosylated mucins in the protection of the respiratory system as well as how mucin-type O-glycosylation may be able to modify viral infectivity. Therefore, we set out to identify the specific genes controlling mucin-type O-glycosylation throughout the mouse respiratory system as well as determine how their expression and the expression of respiratory mucins is influenced by infection or injury. Here, we show that certain mucins and members of the Galnt family are abundantly expressed in specific respiratory tissues/cells and demonstrate unique patterns of O-glycosylation across diverse respiratory tissues. Moreover, we find that the expression of certain Galnts and mucins is altered during lung infection and injury in experimental mice challenged with infectious agents, toxins, and allergens. Finally, we examine gene expression changes of Galnts and mucins in a mouse model of SARS-CoV-2 infection. Our work provides foundational knowledge regarding the specific expression of Galnt enzyme family members and mucins throughout the respiratory system, and how their expression is altered upon lung infection and injury.

Production of Dermatophagoides farinae Having Low Bacterial Content Using Ampicillin

Background

Symbiotic bacteria in house dust mites pose a risk of immunological side effects in the clinical use of immunotherapeutic agents. In this study, we investigated the duration for which the bacterial concentration in Dermatophagoides farinae could be kept low with antibiotic treatment, and whether the allergenic properties of the mite changed under ampicillin treatment.

Methods

D. farinae was cultivated in the presence of ampicillin powder in an autoclaved medium for 6 weeks. After subsequent subcultures without ampicillin, the mites were harvested, and the extract was prepared. The amounts of bacteria, lipopolysaccharides (LPS), and two major allergens (Der f 1 and Der f 2) were measured. Human bronchial epithelial cells and mice were treated with the D. farinae extract to assess the allergic airway inflammation.

Results

The number of bacteria and level of LPS were reduced by 150-fold and 33-fold, respectively, at least 18 weeks after ampicillin treatment. The concentration of Der f 1 and Der f 2 remained unchanged by ampicillin treatment. The secretion of interleukin (IL)-6 and IL-8 from the human airway epithelial cells decreased when treated with the extract of ampicillin-treated D. farinae compared with that of ampicillin-untreated D. farinae. A mouse asthma model was developed using ampicillin-treated D. farinae. We observed that the level of lung function, airway inflammation, and serum-specific immunoglobulin were not different for the mouse asthma model developed using ampicillin-treated D. farinae than the model developed using ampicillin-untreated D. farinae.

Conclusions

We showed that bacterial content in D. farinae was reduced by ampicillin treatment, which was sufficient to induce allergic sensitization and an immune response. This method will be used to develop more controlled allergy immunotherapeutic agents.

House dust mite-induced endoplasmic reticulum stress mediates MUC5AC hypersecretion via TBK1 in airway epithelium

Purpose: Endoplasmic reticulum (ER) stress regulates mucus hypersecretion, and may activate downstream factors via TBK1 signaling to induce gene expression. However, it remains unclear whether ER stress promotes airway mucus secretion through the TBK1 pathway. We aimed to investigate the role of the TBK1 pathway in the regulation of MUC5AC expression in a mouse model of house dust mite (HDM)-induced allergic asthma. Materials and Methods: Mice with HDM-induced asthma and human bronchial epithelial BEAS-2B cells were treated with amlexanox, an anti-allergy drug (25 μM), or 4-PBA (10 mM). Tissue and cell samples were collected. Tissue samples were stained with hematoxylin and eosin (H&E) or periodic acid Schiff (PAS) to evaluate pathology. Protein expression was analyzed by western blotting and immunofluorescence. Results: Mice exposed to HDM presented ER stress and hypersecretion of mucus Muc5ac from airway epithelial cells (p < 0.001). Similar results were observed in BEAS-2B cells following exposure to HDM. Both in vivo and in vitro studies revealed that HDM-induced ER stress induced MUC5AC overexpression via TBK1 signaling. Amlexanox and 4-PBA markedly reduced mucus production and weakened the TBK1 signal, which mediates MUC5AC hypersecretion. Conclusion: TBK1 plays a pivotal role in HDM-induced ER stress, leading to overproduction of MUC5AC in the asthmatic airway epithelium. The overproduction of MUC5AC can be significantly decreased by inhibiting TBK1 or ER stress using 4-PBA. These findings highlight potential target-specific therapies for patients with chronic allergic asthma.

In Vitro Assays for Diagnosis of Drug-Induced Nonsevere Exanthemas: A Systematic Review and Meta-Analysis

Frequent mislabelled causal relationship between drug hypersensitivity reactions and culprit drugs reinforces the need for an accurate diagnosis. The systematic reviews and meta-analyses of in vitro assays published so far focused on immediate reactions and the most severe delayed reactions, while the most frequent drug-induced delayed reactions-nonsevere exanthemas-have been underestimated. We aim to fill this gap. A systematic review of studies on in vitro assays used in the diagnosis of nonsevere drug-induced delayed reactions was conducted following the methodology of Preferred Reporting Items for a Systematic Review and Meta-analysis of Diagnostic Test Accuracy Studies Statement. The EMBASE and PubMed databases were searched. We have included 33 studies from which we extracted the data, then performed meta-analysis where possible, or synthesised the evidence narratively. The quality of the analysed studies was assessed with the QUADAS-2 tool. The tests identified the most frequently were lymphocyte transformation test (LTT), ELISpot, and ELISA. In the meta-analysis carried out for LTT in reactions induce by beta-lactams, the pool estimate of sensitivity and specificity amounted to 49.1% (95% CI: 14.0%, 85.0%) and 94.6% (95% CI: 81.7%, 98.6%), respectively. The studies showed heterogeneity in study design and laboratory settings, which resulted in a wide range of specificity and sensitivity of testing.

Epithelial coxsackievirus adenovirus receptor promotes house dust mite-induced lung inflammation

Airway inflammation and remodelling are important pathophysiologic features in asthma and other respiratory conditions. An intact epithelial cell layer is crucial to maintain lung homoeostasis, and this depends on intercellular adhesion, whilst damaged respiratory epithelium is the primary instigator of airway inflammation. The Coxsackievirus Adenovirus Receptor (CAR) is highly expressed in the epithelium where it modulates cell-cell adhesion stability and facilitates immune cell transepithelial migration. However, the contribution of CAR to lung inflammation remains unclear. Here we investigate the mechanistic contribution of CAR in mediating responses to the common aeroallergen, House Dust Mite (HDM). We demonstrate that administration of HDM in mice lacking CAR in the respiratory epithelium leads to loss of peri-bronchial inflammatory cell infiltration, fewer goblet-cells and decreased pro-inflammatory cytokine release. In vitro analysis in human lung epithelial cells confirms that loss of CAR leads to reduced HDM-dependent inflammatory cytokine release and neutrophil migration. Epithelial CAR depletion also promoted smooth muscle cell proliferation mediated by GSK3β and TGF-β, basal matrix production and airway hyperresponsiveness. Our data demonstrate that CAR coordinates lung inflammation through a dual function in leucocyte recruitment and tissue remodelling and may represent an important target for future therapeutic development in inflammatory lung diseases.

Acute Rhinosinusitis in Children with Inhalant Allergies

Rhinosinusitis is an essential medical problem in pediatric populations. Due to a lack of studies considering allergy impact on pediatric rhinosinusitis, it seems legitimate to investigate this subject. The aim of this paper was to assess the influence of inhalant allergy on acute rhinosinusitis in children. The study involved 100 pediatric patients aged between 3 and 17 years who were admitted to the Chair and Department of Pediatric Otolaryngology, Phoniatrics and Audiology of the Medical University of Lublin due to acute rhinosinusitis. The control group consisted of 50 children without allergy, and the study group consisted of 50 children suffering from inhalant allergy. The methodology employed in this study involved medical history and laryngological examination, as well as laboratory and radiological testing. Dust mite allergy was the most common allergy among patients in the study group. Patients with allergies presented at the hospital later than patients without allergy, and their hospitalization lasted longer due to more severe sinus disease, higher inflammatory parameters, multiple sinus involvement, more frequent fever or rhinosinusitis complications, especially orbital occurrence. Most children in the control group required only pharmacological treatment. Inhalant allergy, especially dust mite allergy, contributes to more severe acute rhinosinusitis in children.

Assessing the impact of air pollutants on clinical visits for childhood allergic respiratory disease induced by house dust mite in Shanghai, China

Background

The prevalence of allergic respiratory disease (ARD) is increasing worldwide during the last few decades, causing a great disease burden especially for children. Air pollution has been increasingly considered as a potential contributor to this trend, but its role in ARD induced by house dust mite (HDM-ARD) remains unclear, especially in time-series study.

Methods

A positive reporting of respiratory allergy to named allergens was included by serum specific IgE testing. A time series Quasi-Poisson regression with distributed lag non-linear model, combined with generalized linear model was used to examine the effects of air pollutants on ARD, HDM-ARD and ARD induced by non-house dust mite (NHDM-ARD).

Results

A total of 16,249 cases of ARD, including 8,719 HDM-ARD and 8,070 NHDM-ARD from 1 Jan 2013 to 31 Dec 2017 were involved in this study. Air pollutants were significantly associated with clinical visits for childhood ARD and HDM-ARD. Exposure to higher O₃ and interquartile range (IQR) increment in O₃ (40.6 µg/m³) increased the risks of clinical visits for childhood HDM-ARD (RR_lag0-5 for the 95th percentile of O₃: 1.26, 95% confidence interval (CI): 1.03, 1.55; RR_lag0-5 for IQR increment (40.6 µg/m³): 1.09, 95% CI: 1.01, 1.17) and ARD (RR_lag0-5 for the 95th percentile of O₃: 1.19, 95% CI: 1.03, 1.38; RR_lag0-5 for IQR increment (40.6 µg/m³): 1.06, 95% CI: 1.01, 1.12). In addition, higher O₃ was associated with increased RR of boys with ARD (RR_lag0-5 for the 95th percentile: 1.26, 95% CI: 1.05, 1.51; RR_lag0-5 for IQR increment (40.6 µg/m³): 1.09, 95% CI: 1.02, 1.16) and HDM-ARD (RR_lag0-5 for the 95th percentile: 1.36, 95% CI: 1.06, 1.75; RR_lag0-5 for IQR increment (40.6 µg/m³): 1.11, 95% CI: 1.02, 1.22), but not in girls.

Conclusions

Exposure to O₃ appeared to be a trigger of clinical visits for childhood ARD, especially for HDM-ARD and boys. These findings provide novel evidence on the impact of air pollution on HDM-ARD, which may have significant implications for designing effective intervention programs to control and prevent childhood ARD, especially HDM-ARD, in China and other similar developing countries.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-01967-1.

Immunological effects of adjuvanted low-dose allergoid allergen-specific immunotherapy in experimental murine house dust mite allergy

BACKGROUND

Native allergen extracts or chemically modified allergoids are routinely used to induce allergen tolerance in allergen-specific immunotherapy (AIT), although mechanistic side-by-side studies are rare. It is paramount to balance optimal dose and allergenicity to achieve efficacy warranting safety. AIT safety and efficacy could be addressed by allergen dose reduction and/or use of allergoids and immunostimulatory adjuvants, respectively. In this study, immunological effects of experimental house dust mite (HDM) AIT were investigated applying high-dose HDM extract and low-dose HDM allergoids with and without the adjuvants microcrystalline tyrosine (MCT) and monophosphoryl lipid A (MPL) in a murine model of HDM allergy.

METHODS

Cellular, humoral, and clinical effects of the different AIT strategies were assessed applying a new experimental AIT model of murine allergic asthma based on physiological, adjuvant-free intranasal sensitization followed by subcutaneous AIT.

RESULTS

While low-dose allergoid and high-dose extract AIT demonstrated comparable potency to suppress allergic airway inflammation and Th2-type cytokine secretion of lung-resident lymphocytes and draining lymph node cells, low-dose allergoid AIT was less effective in inducing a potentially protective IgG1 response. Combining low-dose allergoid AIT with MCT or MCT and dose-adjusted MPL promoted Th1-inducing mechanisms and robust B-cell activation counterbalancing the allergic Th2 immune response.

CONCLUSION

Low allergen doses induce cellular and humoral mechanisms counteracting Th2-driven inflammation by using allergoids and dose-adjusted adjuvants. In light of safety and efficacy improvement, future therapeutic approaches may use low-dose allergoid strategies to drive cellular tolerance and adjuvants to modulate humoral responses.

IFN-γ Attenuates Eosinophilic Inflammation but Is Not Essential for Protection against RSV-Enhanced Asthmatic Comorbidity in Adult Mice

The susceptibility to respiratory syncytial virus (RSV) infection in early life has been associated with a deficient T-helper cell type 1 (Th1) response. Conversely, healthy adults generally do not exhibit severe illness from RSV infection. In the current study, we investigated whether Th1 cytokine IFN-γ is essential for protection against RSV and RSV-associated comorbidities in adult mice. We found that, distinct from influenza virus, prior RSV infection does not induce significant IFN-γ production and susceptibility to secondary Streptococcus pneumoniae infection in adult wild-type (WT) mice. In ovalbumin (OVA)-induced asthmatic mice, RSV super-infection increases airway neutrophil recruitment and inflammatory lung damage but has no significant effect on OVA-induced eosinophilia. Compared with WT controls, RSV infection of asthmatic Ifng^−/− mice results in increased airway eosinophil accumulation. However, a comparable increase in eosinophilia was detected in house dust mite (HDM)-induced asthmatic Ifng^−/− mice in the absence of RSV infection. Furthermore, neither WT nor Ifng^−/− mice exhibit apparent eosinophil infiltration during RSV infection alone. Together, these findings indicate that, despite its critical role in limiting eosinophilic inflammation during asthma, IFN-γ is not essential for protection against RSV-induced exacerbation of asthmatic inflammation in adult mice.

Elovanoids Counteract Inflammatory Signaling, Autophagy, Endoplasmic Reticulum Stress, and Senescence Gene Programming in Human Nasal Epithelial Cells Exposed to Allergens

To contribute to further understanding the cellular and molecular complexities of inflammatory-immune responses in allergic disorders, we have tested the pro-homeostatic elovanoids (ELV) in human nasal epithelial cells (HNEpC) in culture challenged by several allergens. ELV are novel bioactive lipid mediators synthesized from the omega-3 very-long-chain polyunsaturated fatty acids (VLC-PUFA,n-3). We ask if: (a) several critical signaling events that sustain the integrity of the human nasal epithelium and other organ barriers are perturbed by house dust mites (HDM) and other allergens, and (b) if ELV would participate in beneficially modulating these events. HDM is a prevalent indoor allergen that frequently causes allergic respiratory diseases, including allergic rhinitis and allergic asthma, in HDM-sensitized individuals. Our study used HNEpC as an in vitro model to study the effects of ELV in counteracting HDM sensitization resulting in inflammation, endoplasmic reticulum (ER) stress, autophagy, and senescence. HNEpC were challenged with the following allergy inducers: LPS, poly(I:C), or Dermatophagoides farinae plus Dermatophagoides pteronyssinus extract (HDM) (30 µg/mL), with either phosphate-buffered saline (PBS) (vehicle) or ELVN-34 (500 nM). Results show that ELVN-34 promotes cell viability and reduces cytotoxicity upon HDM sensitization of HNEpC. This lipid mediator remarkably reduces the abundance of pro-inflammatory cytokines and chemokines IL-1β, IL-8, VEGF, IL-6, CXCL1, CCL2, and cell adhesion molecule ICAM1 and restores the levels of the pleiotropic anti-inflammatory IL-10. ELVN-34 also lessens the expression of senescence gene programming as well as of gene transcription engaged in pro-inflammatory responses. Our data also uncovered that HDM triggered the expression of key genes that drive autophagy, unfolded protein response (UPR), and matrix metalloproteinases (MMP). ELVN-34 has been shown to counteract these effects effectively. Together, our data reveal a novel, pro-homeostatic, cell-protective lipid-signaling mechanism in HNEpC as potential therapeutic targets for allergies.

Ruxolitinib Ameliorates Airway Hyperresponsiveness and Lung Inflammation in a Corticosteroid-Resistant Murine Model of Severe Asthma

Asthma prevalence has increased considerably over the decades and it is now considered as one of the most common chronic disorders in the world. While the current anti-asthmatic therapies are effective for most asthma patients, there are 5-10% subjects whose disease is not controlled by such agents and they account for about 50% of the asthma-associated healthcare costs. Such patients develop severe asthma (SA), a condition characterized by a dominant Th1/Th17 cytokine response that is accompanied by Type 2 (T2)-low endotype. As JAK (Janus Kinase) signaling is very important for the activation of several cytokine pathways, we examined whether inhibition of JAKs might lessen the clinical and laboratory manifestations of SA. To that end, we employed a recently described murine model that recapitulates the complex immune response identified in the airways of human SA patients. To induce SA, mice were sensitized with house dust mite extract (HDME) and cyclic (c)-di-GMP and then subsequently challenged with HDME and a lower dose of c-di-GMP. In this model, treatment with the JAK inhibitor, Ruxolitinib, significantly ameliorated all the features of SA, including airway hyperresponsiveness and lung inflammation as well as total IgE antibody titers. Thus, these studies highlight JAKs as critical targets for mitigating the hyper-inflammation that occurs in SA and provide the framework for their incorporation into future clinical trials for patients that have severe or difficult-to manage asthma.

Impact of the allergen-specific immunotherapy in pediatric patients with asthma treated at a health institution in Colombia

Introduction: Asthma is a chronic and potentially serious disease and 80% of the cases have an allergic etiology. In this sense, allergen-specific immunotherapy is an alternative that modulates the natural course of the disease. Objective: To evaluate the impact of immunotherapy in pediatric asthma patients treated at a health institution in Colombia. Materials and methods: We conducted an observational descriptive study with an analytical cross-sectional component. Sixty-two patients diagnosed with allergic asthma sensitized to dust mites and treated with at least 6 doses of mite immunotherapy were included. We assessed the impact of immunotherapy using the Asthma Control Test (ACT), the Global Initiative for Asthma (GINA) treatment scale, and spirometry values. Results: The ACT score before the start reported 30% of patients with uncontrolled asthma, 28% with good control, and 4% with totally controlled asthma. Of the patients with uncontrolled asthma, 46.7% achieved good control and 23.3% total control. Regarding patients’ perception of improvement with the immunotherapy, 9.75% perceived a response of less than 50%, 45.2% one between 50% -90%, and 41.9% reported response equal to or greater than 90%. No significant changes in FEV1 values were found in spirometry. Conclusions: Significant changes in the ACT scores and the perception of disease improvement were observed in the population evaluated with specific mite immunotherapy, i.e., it had a positive impact on the natural course of the disease.

Pannexin 1 channels facilitate communication between T cells to restrict the severity of airway inflammation

Allergic airway inflammation is driven by type-2 CD4⁺ T cell inflammatory responses. We uncover an immunoregulatory role for the nucleotide release channel, Panx1, in T cell crosstalk during airway disease. Inverse correlations between Panx1 and asthmatics and our mouse models revealed the necessity, specificity, and sufficiency of Panx1 in T cells to restrict inflammation. Global Panx1^-/- mice experienced exacerbated airway inflammation, and T-cell-specific deletion phenocopied Panx1^-/- mice. A transgenic designed to re-express Panx1 in T cells reversed disease severity in global Panx1^-/- mice. Panx1 activation occurred in pro-inflammatory T effector (Teff) and inhibitory T regulatory (Treg) cells and mediated the extracellular-nucleotide-based Treg-Teff crosstalk required for suppression of Teff cell proliferation. Mechanistic studies identified a Salt-inducible kinase-dependent phosphorylation of Panx1 serine 205 important for channel activation. A genetically targeted mouse expressing non-phosphorylatable Panx1^S205A phenocopied the exacerbated inflammation in Panx1^-/- mice. These data identify Panx1-dependent Treg:Teff cell communication in restricting airway disease.

Establishing a patient registry study database of dust mite allergic asthma in children: design, methodology and preliminary exploration

Background

Asthma is a heterogeneous disease with different phenotypes, endotypes and responses to treatment. Dust mite allergic asthma (DMAA) is the most common type in children. Compared with randomized control trials, a patient registry study (PRS) can reflect the real physical condition and clinical diagnosis more comprehensively.

Methods

Children who visited the asthma clinic of the Children’s Hospital of Chongqing Medical University between August 2018 and August 2020, and met the inclusion criteria and also agreed to participate, were enrolled in the registry study. Clinical information, laboratory tests and peripheral blood samples were collected after informed consent was given by guardians.

Results

To date, 208 children have been enrolled in the patient registry database of DMAA. They are mainly male, with >50% having a history of allergic rhinitis, cesarean section, positive family history and passive smoking. Eosinophils and total immunoglobulin E levels were all significantly higher than normal. According to results for the childhood asthma control test (c-ACT) and ratio of forced expiratory volume in 1 s to predicted value after inhaled corticosteroid treatment, the uncontrolled group had higher hemoglobin (Hb) levels than the control group. The group exhibiting abnormal pulmonary function was older, and had longer disease duration, higher fractional exhaled nitric oxide and Hb than the group in which pulmonary function was restored.

Conclusions

We have preliminarily established a registered study database of children with DMAA. By cluster analysis and using blood samples, we can further study the different pathophysiological mechanisms in order to provide more individualized and targeted treatments for all children.

IL-4Rα blockade reduces influenza-associated morbidity in a murine model of allergic asthma

Background

Asthma was identified as the most common comorbidity in hospitalized patients during the 2009 H1N1 influenza pandemic. We determined using a murine model of allergic asthma whether these mice experienced increased morbidity from pandemic H1N1 (pH1N1) viral infection and whether blockade of interleukin-4 receptor α (IL-4Rα), a critical mediator of T_h2 signalling, improved their outcomes.

Methods

Male BALB/c mice were intranasally sensitized with house dust mite antigen (Der p 1) for 2 weeks; the mice were then inoculated intranasally with a single dose of pandemic H1N1 (pH1N1). The mice were administered intraperitoneally anti-IL-4Rα through either a prophylactic or a therapeutic treatment strategy.

Results

Infection with pH1N1 of mice sensitized to house dust mite (HDM) led to a 24% loss in weight by day 7 of infection (versus 14% in non-sensitized mice; p < .05). This was accompanied by increased viral load in the airways and a dampened anti-viral host responses to the infection. Treatment of HDM sensitized mice with a monoclonal antibody against IL-4Rα prior to or following pH1N1 infection prevented the excess weight loss, reduced the viral load in the lungs and ameliorated airway eosinophilia and systemic inflammation related to the pH1N1 infection.

Conclusion

Together, these data implicate allergic asthma as a significant risk factor for H1N1-related morbidity and reveal a potential therapeutic role for IL-4Rα signalling blockade in reducing the severity of influenza infection in those with allergic airway disease.

Single-cell transcriptomic analysis of allergen-specific T cells in allergy and asthma

CD4⁺ T helper (T_H) cells and regulatory T (T_reg) cells that respond to common allergens play an important role in driving and dampening airway inflammation in patients with asthma. Until recently, direct, unbiased molecular analysis of allergen-reactive T_H and T_reg cells has not been possible. To better understand the diversity of these T cell subsets in allergy and asthma, we analyzed the single-cell transcriptome of ~50,000 house dust mite (HDM) allergen-reactive T_H cells and T_reg cells from asthmatics with HDM allergy and from three control groups: asthmatics without HDM allergy and nonasthmatics with and without HDM allergy. Our analyses show that HDM allergen-reactive T_H and T_reg cells are highly heterogeneous and certain subsets are quantitatively and qualitatively different in individuals with HDM-reactive asthma. The number of interleukin-9 (IL-9)-expressing HDM-reactive T_H cells is greater in asthmatics with HDM allergy compared with nonasthmatics with HDM allergy, and this IL-9-expressing T_H subset displays enhanced pathogenic properties. More HDM-reactive T_H and T_reg cells expressing the interferon response signature (T_HIFNR and T_regIFNR) are present in asthmatics without HDM allergy compared with those with HDM allergy. In cells from these subsets (T_HIFNR and T_regIFNR), expression of TNFSF10 was enriched; its product, tumor necrosis factor-related apoptosis-inducing ligand, dampens activation of T_H cells. These findings suggest that the T_HIFNR and T_regIFNR subsets may dampen allergic responses, which may help explain why only some people develop T_H2 responses to nearly ubiquitous allergens.

Clara cell 16 KDa protein mitigates house dust mite-induced airway inflammation and damage via regulating airway epithelial cell apoptosis in a manner dependent on HMGB1-mediated signaling inhibition

Background

House dust mite (HDM) inhalation can cause airway epithelial damage which is implicated in the process of airway inflammation in asthma. High mobility group box 1 (HMGB1) is critically required for cellular damage and apoptosis as an important endogenous danger signal. Recently, Clara cell 16KDa protein (CC16) has been identified to exert anti-inflammatory and immunomodulatory influence in various injury-related diseases model. However, little is known about its ability to protect against airway epithelial injury in allergic asthma. This study was aimed to clarify the protective roles of CC16 on airway epithelia in HDM-induced asthma and the regulation of HMGB1 by CC16.

Methods

Mice were sensitized and challenged by HDM extract and administrated intranasally with CC16 (5 μg/g or 10 μg/g) or saline in the challenged period. The BEAS-2B human airway epithelial cell line were cultured with CC16 or the control vehicle and then exposed to HDM. Knockdown or overexpression of HMGB1 was induced by cell transfection or intratracheal injection of recombinant adenovirus.

Results

CC16 treatment decreased airway inflammation and histological damage of airway epithelium dose-dependently in HDM-induced asthma model. Airway epithelia apoptosis upon HDM stimulation was noticeably abrogated by CC16 in vivo and in vitro. In addition, upregulation of HMGB1 expression and its related signaling were also detected under HDM conditions, while silencing HMGB1 significantly inhibited the apoptosis of BEAS-2B cells. Furthermore, the activity of HMGB1-mediated signaling was restrained after CC16 treatment whereas HMGB1 overexpression abolished the protective effect of CC16 on HDM-induced airway epithelia apoptosis.

Conclusions

Our data confirm that CC16 attenuates HDM-mediated airway inflammation and damage via suppressing airway epithelial cell apoptosis in a HMGB1-dependent manner, suggesting the role of CC16 as a potential protective option for HDM-induced asthma.

Epithelial-to-mesenchymal transition in neutrophilic chronic rhinosinusitis

PURPOSE OF REVIEW

Barrier dysfunction, tissue fibrosis, and remodeling are essential processes of the pathophysiology of chronic rhinosinusitis (CRS). The role of epithelial-to-mesenchymal transition (EMT) has been assessed in various studies in CRS. In this review, we summarized the pathophysiologic mechanisms of EMT related to CRS, particularly neutrophilic CRS.

RECENT FINDINGS

Loss of epithelial characteristics due to EMT makes leaky epithelium, and transformed mesenchymal cells cause fibrosis and remodeling. Hypoxia, allergens (house dust mites), infections, and air pollutants were related to the pathogenesis of neutrophilic CRS, and these factors are known to induce barrier dysfunction and EMT in sinonasal epithelia. Some molecular pathways related to EMT have been recognized in CRS, including interferon-γ/p38/extracellular signal-regulated kinase, high-mobility group box 1/receptor of advanced glycosylation end-products, TGF-β1/SMAD, and Wnt/β-catenin-signaling pathways. Apart from, several microRNAs (miR-21, miR-761, and miR-30a-5p) have been identified to regulate EMT in CRS.

SUMMARY

EMT is considered to be an important pathogenesis mechanism for CRS. The factors cause EMT in CRS, and the associated molecular mechanisms are related to neutrophilic inflammation. Further studies on CRS endotype and/or phenotype are needed to clarify the implication of EMT on CRS pathogenesis.

House Dust Mite Related Allergic Rhinitis and REM Sleep Disturbances

PURPOSE

Sleep disturbances are common in patients with allergic rhinitis (AR). Perennial allergens like house dust mites (HDM) are difficult to avoid and have nocturnal impacts on the respiratory system and Quality of Life (QOL). The Rapid Eye Movement (REM) sleep stage is associated with memory, cognition, dreams, and overall restfulness, which can be impaired in AR patients with Sleep Disordered Breathing (SDB) even when normal all-night apnea-hypopnea (AHI) or respiratory disturbance (RDI) indices are noted on polysomnography (PSG). We hypothesized that AR HDM allergen positive patients would show REM-specific SDB reflected in their objectively elevated REM-RDI values.

MATERIALS AND METHODS

This retrospective analysis of 100 patients included 47 with HDM positive allergy testing. All patients underwent PSG testing calculating the RDI during REM. Multivariate logistic regression models evaluated relationships between allergic statuses and sleep parameters while controlling for potential confounders.

RESULTS

Compared with allergy negative patients, HDM allergen positive patients were significantly more likely (OR 4.29, 95%CI 1.26-14.62) to have a REM-RDI in the moderate/severe range (≥15 events/h).

CONCLUSIONS

Our study highlighted the significance of respiratory allergies to HDM in patients with SDB. We revealed a significant relationship between HDM allergen positivity and SDB characterized by elevated REM-RDI regardless of all-night AHI, RDI, or REM-AHI values. Clinical implications of knowing about disturbed REM and/or HDM allergenicity include better preparation, treatment, outcomes, and QOL for allergic, SDB, and upper airway surgery patients.

Degradation of bacterial permeability family member A1 (BPIFA1) by house dust mite (HDM) cysteine protease Der p 1 abrogates immune modulator function

Bacterial permeability family member A1 (BPIFA1) is one of the most abundant proteins present in normal airway surface liquid (ASL). It is known to be diminished in asthmatic patients' sputum, which causes airway hyperresponsiveness (AHR). What is currently unclear is how environmental factors, such as allergens' impact on BPIFA1's abundance and functions in the context of allergic asthma. House dust mite (HDM) is a predominant domestic source of aeroallergens. The group of proteases found in HDM is thought to cleave multiple cellular protective mechanisms, and therefore foster the development of allergic asthma. Here, we show that BPIFA1 is cleaved by HDM proteases in a time-, dose-, and temperature-dependent manner. We have also shown the main component in HDM that is responsible for BPIFA1's degradation is Der p1. Fragmented BPIFA1 failed to bind E. coli lipopolysaccharide (LPS), and hence elevated TNFα and IL-6 secretion in human whole blood. BPIFA1 degradation is also observed in vivo in bronchoalveolar fluid (BALF) of mice which are intranasally instilled with HDM. These data suggest that proteases associated with environmental allergens such as HDM cleave BPIFA1 and therefore impair its immune modulator function.

CD2 Regulates Pathogenesis of Asthma Induced by House Dust Mice Extract

Characteristic of allergic asthma, CD4+Th2 lymphocytes secrete Th2 cytokines, interleukin (IL)-4, IL-13, and IL-5 that mediate the inflammatory immune response. Surface expression of CD2 and its ligand, CD58, is increased on the monocytes and eosinophils of asthma patients, which correlate with elevated serum IgE levels, suggesting that CD2 may contribute to allergic airway inflammation. Using a murine model of asthma, we observed that house dust mice extract (HDME)-exposed Balb/c mice have increased airway hyperresponsiveness (AHR), lung inflammation, goblet cell hyperplasia, and elevated levels of Th2 cytokines in the lungs, as well as increased serum IgE levels as compared to the control mice. In contrast, with the exception of serum IgE levels, all the other parameters were significantly reduced in HDME-treated Cd2 ^-/- mice. Interestingly, Il13 but not Il4 or Il5 gene expression in the lungs was dramatically decreased in HDME-exposed Cd2 ^-/- mice. Of note, the gene expression of IL-13 downstream targets (Muc5b and Muc5ac) and high affinity IL-13Rα2 were upregulated in the lungs of HDME-exposed Balb/c mice but were significantly reduced in HDME-exposed Cd2 ^-/- mice. Consistently, gene expression of microRNAs regulating mucin production, inflammation, airway smooth muscle cell proliferation and IL-13 transcripts were increased in the lungs of HDME-exposed Cd2 ^-/- mice. Given the established role of IL-13 in promoting goblet cell hyperplasia, lung inflammation and AHR in allergic asthma, our studies reveal a unique role for CD2 in the regulation of Th2-associated allergic asthma.

Allergen immunotherapy in asthma: current evidence

Background: Allergic asthma is the predominant phenotype in clinical practice. Allergen immunotherapy is the only curative and specific approach for the treatment of allergies with clinical benefits for several years after its discontinuation. Despite advances, the use of allergen immunotherapy in allergic asthma is still suboptimal and controversial.Objective: The purpose of this article is to review the published data about the impact of allergen immunotherapy with the most commonly used allergen extracts on allergic asthma outcomes, including both clinical parameters and patients' subjective experience (quality of life).Methods: As data sources several databases were used, including PubMed, Scopus, Web of Science (2002-2019) and search in English and Spanish languages was performed using the following terms: "allergen immunotherapy" and "asthma" in combination with "house dust mite", "birch pollen", "grass pollen", "olive tree pollen", "molds", "pets" and "asthma quality of life". Randomised control trials and meta-analysis from reviewed publications were selected.Results: Emerging data relating to the positive impact on asthma outcomes of allergen immunotherapy allows the addition of this treatment as a therapeutic option in mild to moderate asthmatics sensitized to house dust mite and pollens. Limited data are available for patients sensitized to molds and pets, as well in severe allergic asthma population.Conclusion: Allergen immunotherapy remains a potential therapeutic option for some patients with allergic asthma. Further research is needed to define the optimal period of treatment, the possible therapeutic role in the treatment of severe allergic asthma, and the cost-effectiveness of allergen immunotherapy in asthmatic patients.

SQ house dust mite sublingual immunotherapy for the treatment of adults with house dust mite-induced allergic rhinitis

Introduction: Allergic rhinitis (AR) is one of the most common chronic conditions affecting both children and adults. The house dust mites (HDM) account for a substantial part of the overall sources of allergens. In patients where allergen avoidance and symptom-relieving pharmacotherapy do not provide adequate disease control, specific allergen immunotherapy (AIT) is indicated. While subcutaneous injection (SCIT) is considered as a time-consuming and invasive treatment regimen, sublingual allergy immunotherapy (SLIT) appears as more convenient treatment strategy.Areas covered: This Drug Profile reviews the clinical data behind the development of the SQ HDM SLIT-tablet, including both the early studies and the pivotal studies, which formed the basis for regulatory approval in Europe, Japan, and the U.S.Expert opinion: The clinical trials behind the development of the SQ HDM-SLIT have demonstrated that the tablet provides a safe, well-tolerated and robust efficacy in the treatment of HDM-induced allergic rhinoconjunctivitis. Further, studies show that the SQ HDM SLIT-tablet is a cost-effective treatment option compared with SCIT.

Diphteria-tetanus-pertussis vaccine reduces specific IgE, inflammation and remodelling in an animal model of mite-induced respiratory allergy

BACKGROUND

Adjuvants, such as bacterial lipopolysaccharides, have been studied to improve the efficacy of allergen-specific immunotherapy. The Bordetella pertussis (Pw) vaccine has been shown to have a protective role in ovalbumin-induced asthma models. However, its role in allergy to mites is unknown. We evaluated the effects of the diphtheria-tetanus-pertussis (DTPw) vaccine on a murine model of respiratory allergy induced by Dermatophagoides pteronyssinus (Derp).

METHODS

In a 30-day protocol, BALB/c mice were immunized subcutaneously with saline or Derp, alone or in combination with diphtheria-tetanus (DT) or DTPw vaccines (days 0, 7 and 14). Subsequently, they underwent a daily intranasal challenge with saline or Derp (days 22-28) and were then sacrificed (day 29). We evaluated serum-specific immunoglobulins, bronchoalveolar lavage (BAL) cellularity, remodelling of the lower airways, density of polymorphonuclear leukocytes (PMNs) and acidic nasal mucus content.

RESULTS

The animals sensitized with Derp produced high levels of specific immunoglobulins, increased density of PMNs and nasal mucus content, and elevated BAL cellularity and remodelling. Vaccines led to a reduction in IgE levels, with the Derp-DTPw group being similar to the saline groups. The vaccinated groups had reductions of BAL cellularity and remodelling, with more expressive results in the Derp-DTPw group compared to the Derp-DT group. The DT and DTPw vaccines inhibited the nasal PMN infiltrate, and DTPw modulated the production of acidic nasal mucus.

CONCLUSIONS

The DTPw vaccine reduced serum specific IgE, nasal and pulmonary inflammation and remodelling of the lower airways.

Osteopontin protects against pneumococcal infection in a murine model of allergic airway inflammation

BACKGROUND

In atopic asthma, chronic Th2-biased inflammation is associated with an increased risk of pneumococcal infection. The anionic phosphoglycoprotein osteopontin (OPN) is highly expressed in asthma and has been ascribed several roles during inflammation. This study aimed to investigate whether OPN affects inflammation and vulnerability to pneumococcal infection in atopic asthma.

METHODS

House dust mite (HDM) extract was used to induce allergic airway inflammation in both wild-type (Spp1^+/+ ) and OPN knockout (Spp1^-/- ) C57BL/6J mice, and the airway was then infected with Streptococcus pneumoniae. Parameters reflecting inflammation, tissue injury, and bacterial burden were measured. In addition, samples from humans with allergic asthma were analyzed.

RESULTS

Both allergen challenge in individuals with allergic asthma and the intranasal instillation of HDM in mice resulted in increased OPN levels in bronchoalveolar lavage fluid (BALF). More immune cells (including alveolar macrophages, neutrophils, eosinophils, and lymphocytes) and higher levels of proinflammatory cytokines were found in Spp1^-/- mice than in Spp1^+/+ mice. Moreover, OPN-deficient mice exhibited increased levels of markers reflecting tissue injury. Upon infection with S. pneumoniae, Spp1^+/+ mice with allergic airway inflammation had a significantly lower bacterial burden in both BALF and lung tissue than did Spp1^-/- mice. Furthermore, Spp1^-/- mice had higher levels of cytokines and immune cells in BALF than did Spp1^+/+ mice.

CONCLUSION

OPN reduces inflammation, decreases tissue injury, and reduces bacterial loads during concurrent pneumococcal infection and allergic airway inflammation in a murine model. These findings suggest that OPN significantly affects vulnerability to pneumococcal infection in atopic asthma.

House dust mite sublingual immunotherapy in allergic rhinitis

Allergen immunotherapy has been shown to be effective in treatment of allergic rhinitis (AR). Sublingual immunotherapy (SLIT) is generally recommended for treating seasonal AR in adults and children; however, questions remain in regard to AR treatment in relation to house dust mite (HDM). Due to heterogeneous formulations, different outcome reporting systems, and the lack of a standardized dose, HDM SLITs have not been standardized in published studies. Nevertheless, studies continuously report positive effects of HDM SLIT in AR, and HDM SLIT remains a treatment option for patients with HDM-induced allergic asthma that frequently co-exists with AR. Therefore, it is likely that HDM SLIT usage will increase. This review will focus on HDM SLIT in AR exclusively.

Allergic asthma: an overview of metabolomic strategies leading to the identification of biomarkers in the field

Allergic asthma is a prominent disease especially during childhood. Indoor allergens, in general, and particularly house dust mites (HDM) are the most prevalent sensitizers associated with allergic asthma. Available data show that 65-130 million people are mite-sensitized world-wide and as many as 50% of these are asthmatic. In fact, sensitization to HDM in the first years of life can produce devastating effects on pulmonary function leading to asthmatic syndromes that can be fatal. To date, there has been considerable research into the pathological pathways and structural changes associated with allergic asthma. However, limitations related to the disease heterogeneity and a lack of knowledge into its pathophysiology have impeded the generation of valuable data needed to appropriately phenotype patients and, subsequently, treat this disease. Here, we report a systematic and integral analysis of the disease, from airway remodelling to the immune response taking place throughout the disease stages. We present an overview of metabolomics, the management of complex multifactorial diseases through the analysis of all possible metabolites in a biological sample, obtaining a global interpretation of biological systems. Special interest is placed on the challenges to obtain biological samples and the methodological aspects to acquire relevant information, focusing on the identification of novel biomarkers associated with specific phenotypes of allergic asthma. We also present an overview of the metabolites cited in the literature, which have been related to inflammation and immune response in asthma and other allergy-related diseases.

Der f1 induces pyroptosis in human bronchial epithelia via the NLRP3 inflammasome

Damage to the bronchial epithelium leads to persistent inflammation and airway remodelling in various respiratory diseases, such as asthma and chronic obstructive pulmonary disease. To date, the mechanisms underlying bronchial epithelial cell damage and death by common allergens remain largely unknown. The aim of the present study was to investigate Der f1, an allergen of Dermatophagoides farinae, which may result in the death of human bronchial epithelial cells (HBECs). Der f1 induces BECs to undergo the inflammatory cell death referred to as pyroptosis, induced by increasing lactate dehydrogenase release and propidium iodide penetration. Stimulation by Der f1 enhances interleukin (IL)‑1β cleavage and release, which is associated with caspase‑1 activation. In addition, the NOD‑like receptor family pyrin domain‑containing 3 (NLRP3), is required for the activation of caspase‑1 through increasing the formation of the inflammasome complex. Consistent with these findings, pre‑treatment of HBECs with a caspase‑1 inhibitor, or silencing of NLRP3 by siRNA transfection, reduced Der f1‑mediated IL‑1β and pyroptosis. Therefore, the common allergen Der f1 was not only found to induce allergy, but also led to pyroptosis and IL‑1β secretion via the NLRP3‑caspase‑1 inflammasome in HBECs. This newly identified connection of the Der f1 allergen with BEC damage and inflammation may play an important role in the pathogenesis of asthma.

The independent effects of vitamin D deficiency and house dust mite exposure on lung function are sex-specific

Vitamin D deficiency is increasing around the world and has been associated with the development of asthma. This study aims to evaluate the effect of dietary vitamin D deficiency at different life stages on lung function using a murine model of allergic airways disease. BALB/c mice were challenged intranasally with HDM or saline alone for 10 days. Twenty four hours after the last challenge, mice were anesthetized and lung function was measured using the forced oscillation technique (FOT). Mice were euthanized for assessment of inflammation in the bronchoalveolar lavage (BAL) and total collagen content in lung homogenates by ELISA. Vitamin D deficiency impaired lung function in both male and female mice, increasing tissue damping and elastance, however had no effect on HDM induced inflammation. The impact of vitamin D deficiency was more evident in females. HDM also decreased airway distensibility, but only in females and this response was not altered by vitamin D deficiency. Our data suggest that vitamin D deficiency and HDM exposure have independent effects on lung mechanics and that females are more susceptible to these effects. Vitamin D deficiency may exacerbate lung function deficits by having a direct, but independent, effect on parenchymal mechanics.

Aeroallergen Der p 2 promotes motility of human non-small cell lung cancer cells via toll-like receptor-mediated up-regulation of urokinase-type plasminogen activator and integrin/focal adhesion kinase signaling

House dust mite (HDM) allergens are one of the major causes leading to respiratory hypersensitiveness and airway remodeling. Here we hypothesized that a major HDM allergen Der p 2 could increase cell motility and invasiveness of non-small cell lung cancer (NSCLC) cells. Our results showed that low dose (1 and 3 μg/mL) recombinant Der p 2 protein (DP2) enhanced the migration and invasiveness of human NSCLC cell A549, H1299 and CL1-5, but nonsignificantly altered their growth. Further investigation revealed that integrin αV level was increased and its downstream signaling including focal adhesion kinase (FAK) and paxillin were activated in A549 cells exposed to DP2. In parallel, DP2 also activated the FAK-associated signaling effectors such as Src, phosphatidyl inositol 3-kinase (PI3K), AKT, p38 mitogen-activated protein kinase (P38), extracellular signal-regulated kinase 1/2 (ERK1/2) and c-Jun N-terminal kinase (JNK). Our findings also revealed that DP2 increased expression level of urokinase type plasminogen-activated kinase (uPA) and uPA receptor (uPAR), and subsequently enhanced the binding of uPAR to integrin αV. Moreover, the involvement of toll-like receptor 2/4 (TLR2/4)-triggered ERK1/2 activation in the increased expression of uPA and uPAR was also demonstrated. Collectively, these findings indicate that DP2 can enhance cell motility and invasiveness of NSCLC cells, attributing to TLR2/4-ERK1/2 activation, increased uPA and uPAR expression, enhanced binding of uPAR to integrin αV, and the consequent FAK signaling cascades. Thus, we suggest that DP2 may exacerbate NSCLC via promoting metastatic ability of carcinoma cell.

Natural Evolution of IgE Responses to Mite Allergens and Relationship to Progression of Allergic Disease: a Review

PURPOSE OF REVIEW

Allergenic molecules of the house dust mite (HDM) are crucially important indoor allergens, contributing to allergic rhinitis and asthma around the globe. In the past years, recombinant molecules for diagnostics opened new pathways to investigate individual sensitization profiles and new chances for the prevention and treatment of HDM allergy. This review summarizes the latest findings on the evolution of IgE responses towards mite allergens.

RECENT FINDINGS

Several cross-sectional and longitudinal studies confirmed the role of Der p 1 and Der p 2 as major allergenic proteins of the HDM. A newly identified player is the major allergen Der p 23. Apart from identifying the early sensitization towards this molecule as a risk factor for asthma in school age, a recent longitudinal study described sensitization patterns showing that the production of IgE usually starts towards a group of initiator proteins and may stay monomolecular or expand to an oligo- or even polymolecular stage. This phenomenon also correlates to clinical symptoms. A relation between a broad sensitization pattern and symptom severity has also been shown cross-sectionally. Individual sensitization profiles towards HDM allergens provide important information to evaluate a patient's current stage and risk for clinical symptoms. This knowledge paves the way for an early and adequate prevention and/or treatment.

The environment, epigenome, and asthma

Asthma prevalence has been on the increase, especially in North America compared with other continents. However, the prevalence of asthma differs worldwide, and in many countries the prevalence is stable or decreasing. This highlights the influence of environmental exposures, such as allergens, air pollution, and the environmental microbiome, on disease etiology and pathogenesis. The epigenome might provide the unifying mechanism that translates the influence of environmental exposures to changes in gene expression, respiratory epithelial function, and immune cell skewing that are hallmarks of asthma. In this review we will introduce the concept of the environmental epigenome in asthmatic patients, summarize previous publications of relevance to this field, and discuss future directions.

Enhanced expression of Organic Cation Transporters in bronchial epithelial cell layers following insults associated with asthma - Impact on salbutamol transport

Increasing evidence suggests Organic Cation Transporters (OCT) might facilitate the absorption of inhaled bronchodilators, including salbutamol, across the lung epithelium. This is essentially scarred and inflamed in asthma. Accordingly, the impact of epithelial insults relevant to asthma on OCT expression and salbutamol transport was evaluated in air-liquid interfaced layers of the human broncho-epithelial cell line Calu-3. These were physically injured and allowed to recover for 48h or exposed to the pro-inflammatory stimulant lipopolysaccharide (LPS) for 48h and the aeroallergen house dust mite (HDM) for 8h twice over 48h. Increases in transporter expression were measured following each treatment, with the protein levels of the OCTN2 subtype consistently raised by at least 50%. Interestingly, OCT upregulation upon LPS and HDM challenges were dependent on an inflammatory event occurring in the cell layers. Salbutamol permeability was higher in LPS exposed layers than in their untreated counterparts and in both cases, was sensitive to the OCT inhibitor tetraethylammonium. This study is the first to show epithelial injury, inflammation and allergen abuse upregulate OCT in bronchial epithelial cells, which might have an impact on the absorption of their substrates in diseased lungs.

Secretoglobin Superfamily Protein SCGB3A2 Alleviates House Dust Mite-Induced Allergic Airway Inflammation in Mice

BACKGROUND

Secretoglobin (SCGB) 3A2, a novel, lung-enriched, cytokine-like, secreted protein of small molecular weight, was demonstrated to exhibit various biological functions including anti-inflammatory, antifibrotic and growth-factor activities. Anti-inflammatory activity was uncovered using the ovalbumin-induced allergic airway inflammation model. However, further validation of this activity using knockout mice in a different allergic inflammation model is necessary in order to establish the antiallergic inflammatory role for this protein.

METHODS

Scgb3a2-null (Scgb3a2-/-) mice were subjected to nasal inhalation of Dermatophagoides pteronyssinus extract for 5 days/week for 5 consecutive weeks; control mice received nasal inhalation of saline as a comparator. Airway inflammation was assessed by histological analysis, the number of inflammatory cells and various Th2-type cytokine levels in the lungs and bronchoalveolar lavage fluids by qRT-PCR and ELISA, respectively.

RESULTS

Exacerbated inflammation was found in the airway of Scgb3a2-/- mice subjected to house dust mite (HDM)-induced allergic airway inflammation compared with saline-treated control groups. All the inflammation end points were increased in the Scgb3a2-/- mice. The Ccr4 and Ccl17 mRNA levels were higher in HDM-treated lungs of Scgb3a2-/- mice than wild-type mice or saline-treated Scgb3a2-/- mice, whereas no changes were observed for Ccr3 and Ccl11 mRNA levels.

CONCLUSIONS

These results demonstrate that SCGB3A2 has an anti-inflammatory activity in the HDM-induced allergic airway inflammation model, in which SCGB3A2 may modulate the CCR4-CCL17 pathway. SCGB3A2 may provide a useful tool to treat allergic airway inflammation, and further studies on the levels and function of SCGB3A2 in asthmatic patients are warranted.

A review on emerging frontiers of house dust mite and cockroach allergy research

Currently, mankind is afflicted with diversified health issues, allergies being a common, yet little understood malady. Allergies, the outcome of a baffled immune system encompasses myriad allergens and causes an array of health consequences, ranging from transient to recurrent and mild to fatal. Indoor allergy is a serious hypersensitivity in genetically-predisposed people, triggered by ingestion, inhalation or mere contact of allergens, of which mite and cockroaches are one of the most-represented constituents. Arduous to eliminate, these aeroallergens pose constant health challenges, mostly manifested as respiratory and dermatological inflammations, leading to further aggravations if unrestrained. Recent times have seen an unprecedented endeavour to understand the conformation of these allergens, their immune manipulative ploys and other underlying causes of pathogenesis, most importantly therapies. Yet a large section of vulnerable people is ignorant of these innocuous-looking immune irritants, prevailing around them, and continues to suffer. This review aims to expedite this field by a concise, informative account of seminal findings in the past few years, with particular emphasis on leading frontiers like genome-wide association studies (GWAS), epitope mapping, metabolomics etc. Drawbacks linked to current approaches and solutions to overcome them have been proposed.

The nasal methylome and childhood atopic asthma

BACKGROUND

Given the strong environmental influence on both epigenetic marks and allergic asthma in children, the epigenetic alterations in respiratory epithelia might provide insight into allergic asthma.

OBJECTIVE

We sought to identify DNA methylation and gene expression changes associated with childhood allergic persistent asthma.

METHODS

We compared genomic DNA methylation patterns and gene expression in African American children with persistent atopic asthma (n = 36) versus healthy control subjects (n = 36). Results were validated in an independent population of asthmatic children (n = 30) by using a shared healthy control population (n = 36) and in an independent population of white adult atopic asthmatic patients (n = 12) and control subjects (n = 12).

RESULTS

We identified 186 genes with significant methylation changes, differentially methylated regions or differentially methylated probes, after adjustment for age, sex, race/ethnicity, batch effects, inflation, and multiple comparisons. Genes differentially methylated included those with established roles in asthma and atopy and genes related to extracellular matrix, immunity, cell adhesion, epigenetic regulation, and airflow obstruction. The methylation changes were substantial (median, 9.5%; range, 2.6% to 29.5%). Hypomethylated and hypermethylated genes were associated with increased and decreased gene expression, respectively (P < 2.8 × 10^-6 for differentially methylated regions and P < 7.8 × 10^-10 for differentially methylated probes). Quantitative analysis in 53 differentially expressed genes demonstrated that 32 (60%) have significant methylation-expression relationships within 5 kb of the gene. Ten loci selected based on the relevance to asthma, magnitude of methylation change, and methylation-expression relationships were validated in an independent cohort of children with atopic asthma. Sixty-seven of 186 genes also have significant asthma-associated methylation changes in nasal epithelia of adult white asthmatic patients.

CONCLUSIONS

Epigenetic marks in respiratory epithelia are associated with allergic asthma and gene expression changes in inner-city children.

Characteristics of Allergic Pulmonary Inflammation in CXCR3Knockout Mice Sensitized and Challenged with House Dust Mite Protein

Chemokine C-X-C motif receptor 3 (CXCR3) is a chemokine receptor that is mainly expressed by activated T lymphocytes. T cells play important roles in allergic pulmonary inflammation, which is a hallmark of asthma and elicits the localized accumulation of activated T cells in the lung. In China, a marked increase in the incidence rate of chronic allergic pulmonary inflammation has made it a major public health threat. In the present study, we investigated the role of CXCR3 and its ligands in airway inflammation induced by house dust mite protein (HDMP) in a CXCR3 knockout (CXCR3KO) asthma mouse model. Pathological manifestations in the lung, cell counts and bronchoalveolar lavage fluid (BALF) classifications were studied using hematoxylin and eosin (H&E) staining. The levels of IL-4 and IFN-γ in the BALF and splenocyte supernatants were measured using ELISA. CD4+ and CD8+ T cells in the lung and spleen were analyzed by flow cytometry. RT-PCR was applied to measure the mRNA transcript levels of monokines induced by IFN-γ(CXCL9) and IFN-γ inducible protein 10(CXCL10). The total cell counts, eosinophil counts, and IL-4 levels in the BALF and cultured splenocyte supernatants were significantly increased, while the levels of IFN-γ were reduced in the HDMP groups(P<0.01). Changes in the total cell counts, eosinophil counts, and lymphocyte counts, as well as the total protein levels in the BALF, the levels of IL-4 in splenocyte supernatants, and the pathological manifestations in the lung, were all greater in CXCR3KO mice than in C57BL/6 wild-type mice. Furthermore, the expression levels of CXCL9 and CXCL10 mRNA transcripts in the lungs of CXCR3KO mice were lower than those in C57BL/6 wild-type mice (P<0.05). CXCR3 and its ligands (i.e., CXCL9 and CXCL10) may play anti-inflammatory roles in this animal model. Promoting the expression of CXCR3 and its ligands may represent a novel therapeutic approach for preventing and curing asthma.

TIM-3 is not essential for development of airway inflammation induced by house dust mite antigens

Background

T cell immunoglobulin domain and mucin domain-containing molecule 3 (TIM-3), which is preferentially expressed on Th1 cells rather than Th2 cells, is considered to be a negative regulator of Th1 cell function. This suggests that TIM-3 indirectly enhances Th2-type immune responses by suppressing Th1 cell function.

Methods

To investigate TIM-3's possible involvement in Th2-type acute and chronic airway inflammation, wild-type and TIM-3-deficient (TIM-3^−/−) mice were sensitized and challenged with a house dust mite (HDM) extract. Airway inflammation and the number of inflammatory cells in bronchoalveolar lavage fluids (BALFs) in the mice were determined by histological analysis and with a hemocytometer, respectively. Expression of mRNA in the lungs was determined by quantitative PCR, while the levels of cytokines in the BALFs and IgE in sera were determined by ELISA.

Results

Despite constitutive expression of TIM-3 mRNA in the lungs, the number of eosinophils in bronchoalveolar lavage fluids (BALFs) and the score of pulmonary inflammation were comparable between wild-type and TIM-3^−/− mice during both acute and chronic HDM-induced airway inflammation. On the other hand, the number of lymphocytes in the BALFs of TIM-3^−/− mice was significantly increased compared with wild-type mice during HDM-induced chronic, but not acute, airway inflammation, while the levels of Th2 cytokines in the BALFs and HDM-specific IgG1 and IgG2a and total IgE in the sera were comparable in both groups.

Conclusions

Our findings indicate that, in mice, TIM-3 is not essential for development of HDM-induced acute or chronic allergic airway inflammation, although it appears to be involved in reduced lymphocyte recruitment during HDM-induced chronic allergic airway inflammation.

The relationships among Dermatophagoides pteronyssinus exposure, exhaled nitric oxide, and exhaled breath condensate pH levels in atopic asthmatic children

This study examined seasonal changes in indoor Dermatophagoides pteronyssinus 1 (Der p 1)/Blattella germanica 1 (Bla g 1) antigen concentrations in the homes of atopic asthmatic and atopic nonasthmatic children. Possible associations between environmental allergen exposure and levels of exhaled breath indices were also evaluated.A total of 38 atopic children were recruited for this cross-sectional study: 22 were asthmatic and 16 were nonasthmatic. Home visits were conducted for indoor air and dust sampling each season. Exhaled nitric oxide (eNO)/spirometric measurements were taken and exhaled breath condensate (EBC) was collected after sampling of the domestic environment.The highest Der p 1 concentrations were on the top of mattresses in the homes of recruited children. The floors of kitchens and living rooms had the highest Bla g 1 concentrations in the homes of atopic asthmatic children. A positive correlation was found between Der p 1 exposure of mattress, bedroom floor, and living room floor and eNO levels in the atopic asthmatic children. The Der p 1 concentrations on the surfaces of mattress and bedroom floor were positively related to high eNO levels in the atopic asthmatic children after adjusting for season. No association was found between Der p 1 exposure and EBC pH values in the recruited children.A positive correlation was found between Der p 1 exposure and high eNO levels in atopic asthmatic children, especially in Der p 1 exposure of mattress and bedroom floor.

Efficacy and safety of SQ house dust mite (HDM) SLIT-tablet treatment of HDM allergic asthma

INTRODUCTION

In the treatment of house dust mite (HDM) respiratory allergic disease, allergy immunotherapy constitutes an add-on treatment option targeting the underlying immunological mechanisms of allergic disease. However, for the treatment of HDM allergic asthma, the use of subcutaneous allergy immunotherapy (SCIT) has been limited by the risk of systemic adverse events. Thus, sublingually administered allergy immunotherapy (SLIT) has been investigated as a treatment option with an improved tolerability profile that allows for safer treatment of patients with HDM allergic asthma.

AREAS COVERED

In this Drug Profile, we provide a review of the clinical data behind the SQ HDM SLIT-tablet, which was recently approved for the treatment of HDM allergic asthma and allergic rhinitis by regulatory authorities in several European countries. Expert commentary: The SQ HDM SLIT-tablet is the first allergy immunotherapy to be tested prospectively in patients with asthma, and to favorably modify patient relevant end points such as requirement for inhaled corticosteroid (ICS) or the time to first asthma exacerbation upon ICS reduction, suggesting that SQ HDM SLIT-tablet treatment may contribute to improving overall asthma control.

The association between maternal psychological stress and inflammatory cytokines in allergic young children

Background. Previous studies have shown that psychological stress is linked to asthma prevalence. Parental psychological stress may potentially influence inflammatory responses in their allergic children. The purpose of this study is to clarify the association between maternal psychological status and inflammatory response of allergic young children.

Methods. The study subjects were 152 young allergic children (median age: 13 months) who had not shown any allergic symptoms in the past one month. mRNA expression levels of the inflammatory response genes IL-6, IL-8, IL-10 and IL-22 were quantified by qRT-PCR. Maternal psychological status was assessed by standardized questionnaires: the Centre for Epidemiological Studies Depression Scale (CES-D) for depression and the Japanese Perceived Stress Scale (JPSS) for perceived stress.

Results. A significant positive association was observed between maternal CES-D scores and IL-6 mRNA expression in the children with asthma. The JPSS scores were also positively associated with IL-8 mRNA expression in asthmatic children and IL-6 mRNA expression in children with allergic rhinitis. Similar trends were observed among children positive for house dust mite-specific IgE, but these associations were not significant.

Conclusion. This study supports the hypothesis that maternal psychological stress affects the inflammatory response in their allergic children.

Biosignature for airway inflammation in a house dust mite-challenged murine model of allergic asthma

House dust mite (HDM) challenge is commonly used in murine models of allergic asthma for preclinical pathophysiological studies. However, few studies define objective readouts or biomarkers in this model. In this study we characterized immune responses and defined molecular markers that are specifically altered after HDM challenge. In this murine model, we used repeated HDM challenge for two weeks which induced hallmarks of allergic asthma seen in humans, including airway hyper-responsiveness (AHR) and elevated levels of circulating total and HDM-specific IgE and IgG1. Kinetic studies showed that at least 24 h after last HDM challenge results in significant AHR along with eosinophil infiltration in the lungs. Histologic assessment of lung revealed increased epithelial thickness and goblet cell hyperplasia, in the absence of airway wall collagen deposition, suggesting ongoing tissue repair concomitant with acute allergic lung inflammation. Thus, this model may be suitable to delineate airway inflammation processes that precede airway remodeling and development of fixed airway obstruction. We observed that a panel of cytokines e.g. IFN-γ, IL-1β, IL-4, IL-5, IL-6, KC, TNF-α, IL-13, IL-33, MDC and TARC were elevated in lung tissue and bronchoalveolar fluid, indicating local lung inflammation. However, levels of these cytokines remained unchanged in serum, reflecting lack of systemic inflammation in this model. Based on these findings, we further monitored the expression of 84 selected genes in lung tissues by quantitative real-time PCR array, and identified 31 mRNAs that were significantly up-regulated in lung tissue from HDM-challenged mice. These included genes associated with human asthma (e.g. clca3, ear11, il-13, il-13ra2, il-10, il-21, arg1 and chia1) and leukocyte recruitment in the lungs (e.g. ccl11, ccl12 and ccl24). This study describes a biosignature to enable broad and systematic interrogation of molecular mechanisms and intervention strategies for airway inflammation pertinent to allergic asthma that precedes and possibly potentiates airway remodeling and fibrosis.

Summary: This study describes a systematic analysis of molecular end points in an murine model of allergic asthma. The biosignature described can be used to interrogate molecular mechanisms and intervention strategies for airway inflammation pertinent to allergic asthma that precedes and possibly potentiates airway remodeling and fibrosis.

Induction of nasal polyps using house dust mite and Staphylococcal enterotoxin B in C57BL/6 mice

BACKGROUND

The murine polyp model was developed previously using ovalbumin and Staphylococcus aureus enterotoxin B (SEB). Here, we established a model mimicking key aspects of chronic eosinophilic rhinosinusitis with nasal polyps using the house dust mite (HDM), a clinically relevant aeroallergen, co-administered with SEB. We assessed the inflammatory response and formation of nasal polypoid lesions in an experimental murine model using intranasal delivery of HDM and ovalbumin.

METHODS

After induction of HDM-induced allergic rhinosinusitis in C57BL/6 mice, SEB (10ng) was instilled into the nasal cavity of mice for eight weeks. Phosphate-buffered saline-challenged mice served as control. Histopathological changes were evaluated using haematoxylin and eosin for overall inflammation, Sirius red for eosinophils, and periodic acid-Schiff stain for goblet cells. The distribution of mast cells in mouse nasal tissue was determined by immunohistochemistry. Serum total IgE was measured using enzyme-linked immunosorbent assay.

RESULTS

Compared to mice treated with HDM only, the HDM+SEB-treated mice demonstrated nasal polypoid lesion formation and a significant increase in the number of secretory cells and eosinophilic infiltration. Moreover, mice challenged intranasally with HDM showed highly abundant mast cells in the nasal mucosa. In contrast, OVA+SEB-challenged mice showed a significantly lower degree of mast cell infiltration.

CONCLUSION

We established an in vivo model of chronic allergic rhinosinusitis with nasal polypoid lesions using HDM aeroallergen. This study demonstrated that the HDM+SEB-induced murine polyp model could be utilised as a suitable model for nasal polyps, especially with both eosinophil and mast cell infiltration.

House Dust Mite Respiratory Allergy: An Overview of Current Therapeutic Strategies

Although house dust mite (HDM) allergy is a major cause of respiratory allergic disease, specific diagnosis and effective treatment both present unresolved challenges. Guidelines for the treatment of allergic rhinitis and asthma are well supported in the literature, but specific evidence on the efficacy of pharmacotherapy treatment for known HDM-allergic patients is weaker. The standard diagnostic techniques--skin prick test and specific IgE testing--can be confounded by cross-reactivity. However, component-resolved diagnosis using purified and recombinant allergens can improve the accuracy of specific IgE testing, but availability is limited. Treatment options for HDM allergy are limited and include HDM avoidance, which is widely recommended as a strategy, although evidence for its efficacy is variable. Clinical efficacy of pharmacotherapy is well documented; however, symptom relief does not extend beyond the end of treatment. Finally, allergen immunotherapy has a poor but improving evidence base (notably on sublingual tablets) and its benefits last after treatment ends. This review identifies needs for deeper physician knowledge on the extent and impact of HDM allergy in respiratory disease, as well as further development and improved access to molecular allergy diagnosis. Furthermore, there is a need for the development of better-designed clinical trials to explore the utility of allergen-specific approaches, and uptake of data into guidance for physicians on more effective diagnosis and therapy of HDM respiratory allergy in practice.

Development of an experimental model of maternal allergic asthma during pregnancy

Maternal asthma during pregnancy adversely affects pregnancy outcomes but identification of the cause/s, and the ability to evaluate interventions, is limited by the lack of an appropriate animal model. We therefore aimed to characterise maternal lung and cardiovascular responses and fetal-placental growth and lung surfactant levels in a sheep model of allergic asthma. Immune and airway functions were studied in singleton-bearing ewes, either sensitised before pregnancy to house dust mite (HDM, allergic, n = 7) or non-allergic (control, n = 5), and subjected to repeated airway challenges with HDM (allergic group) or saline (control group) throughout gestation. Maternal lung, fetal and placental phenotypes were characterised at 140 ± 1 days gestational age (term, ∼147 days). The eosinophil influx into lungs was greater after HDM challenge in allergic ewes than after saline challenge in control ewes before mating and in late gestation. Airway resistance increased throughout pregnancy in allergic but not control ewes, consistent with increased airway smooth muscle in allergic ewes. Maternal allergic asthma decreased relative fetal weight (-12%) and altered placental phenotype to a more mature form. Expression of surfactant protein B mRNA was 48% lower in fetuses from allergic ewes than controls, with a similar trend for surfactant protein D. Thus, allergic asthma in pregnant sheep modifies placental phenotype, and inhibits fetal growth and lung development consistent with observations from human pregnancies. Preconceptional allergen sensitisation and repeated airway challenges in pregnant sheep therefore provides an animal model to identify mechanisms of altered fetal development and adverse pregnancy outcomes caused by maternal asthma in pregnancy.

Quantitative Polymerase Chain Reaction Analysis of the Mouse Cyp2j Subfamily: Tissue Distribution and Regulation

Members of the cytochrome P450 CYP2J subfamily are expressed in multiple tissues in mice and humans. These enzymes are active in the metabolism of fatty acids to generate bioactive compounds. Herein we report new methods and results for quantitative polymerase chain reaction (qPCR) analysis for the seven genes (Cyp2j5, Cyp2j6, Cyp2j8, Cyp2j9, Cyp2j11, Cyp2j12, and Cyp2j13) of the mouse Cyp2j subfamily. SYBR Green primer sets were developed and compared with commercially available TaqMan primer/probe assays for specificity toward mouse Cyp2j cDNA, and analysis of tissue distribution and regulation of Cyp2j genes. Each TaqMan primer/probe set and SYBR Green primer set were shown to be specific for their intended mouse Cyp2j cDNA. Tissue distribution of the mouse Cyp2j isoforms confirmed similar patterns of expression between the two qPCR methods. Cyp2j5 and Cyp2j13 were highly expressed in male kidneys, and Cyp2j11 was highly expressed in both male and female kidneys. Cyp2j6 was expressed in multiple tissues, with the highest expression in the small intestine and duodenum. Cyp2j8 was detected in various tissues, with highest expression found in the skin. Cyp2j9 was highly expressed in the brain, liver, and lung. Cyp2j12 was predominately expressed in the brain. We also determined the Cyp2j isoform expression in Cyp2j5 knockout mice to determine whether there was compensatory regulation of other Cyp2j isoforms, and we assessed Cyp2j isoform regulation during various inflammatory models, including influenza A, bacterial lipopolysaccharide, house dust mite allergen, and corn pollen. Both qPCR methods detected similar suppression of Cyp2j6 and Cyp2j9 during inflammation in the lung.