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

One-strength dose escalation of house dust mite depot product for subcutaneous immunotherapy is safe and tolerable

BACKGROUND

Allergen immunotherapy (AIT) aims at modulating the immune response by administration of allergen preparations at regular intervals over several years (1). For subcutaneous AIT (SCIT), the treatment is initiated with a dose escalation phase followed by a maintenance dose administration. Over the last decade, there has been a trend towards shortening dose escalation regimens to increase patient adherence. This open-label, phase II trial aimed to investigate the safety and tolerability of a house dust mites (HDMs) SCIT product when used in a newly designed one-strength dose escalation scheme.

METHOD

Patients, aged 12-65, suffering from HDM-allergic rhinitis/rhinoconjunctivitis ± asthma were included. Patients were randomized to the one-strength (6 injections from the highest strength 3) or the Standard dose escalation regimen (14 injections from strengths 1 to 3) using the HDMs-SCIT product. All adverse events were reported. Tolerability was assessed on the Likert scale.

RESULTS

One hundred and forty-three patients were randomized, 79 adults and 64 adolescents. In total, the one-strength regimen caused more adverse drug reactions (ADRs) than the Standard regimen (p = .0457). With both regimens most ADRs were local reactions which occurred more often in the one-strength group (p = .0393). But there was no significant difference in the number of patients affected by systemic or serious ADRs between both regimens. No relevant differences occurred between the two age groups and no other risks were observed for adolescents compared to adults.

CONCLUSION

The safety and tolerability of both regimens can be considered comparable, as most ADRs were local reactions, primarily rated as mild in intensity. Nevertheless, the one-strength regimen caused more ADRs. Reducing the number of injections from 14 to 6 while using only one strength offers the potential to improve patient adherence which further might increase clinical efficacy. Future trials could confirm this hypothesis.

Suppression of Pathological Allergen-Specific B Cells by Protein-Engineered Molecules in a Mouse Model of Chronic House Dust Mite Allergy

Der p1 is one of the major allergens causing house dust mite (HDM) allergy. Pathological Der p1-specific B cells play a key role in allergic inflammation as producers of allergen-specific antibodies. Crosslinking the inhibitory FcγRIIb with the B cell receptor triggers a high-affinity suppressive signal in B cells. Selective elimination of allergen-specific cells could potentially be achieved by administering chimeric molecules that combine, through protein engineering, the FcγRIIb-targeting monoclonal 2.4G2 antibody with the epitope-carrying Dp52-71 peptides from Der p1. We tested this hypothesis, in a chronic mouse model of HDM allergy induced in BalB/c mice, using FACS and ELISA assays, along with histopathological and correlational analyses. Dp52-71chimera treatment of HDM-challenged mice led to a decrease in serum anti-HDM IgG1 antibodies, a reduction in BALF β-hexosaminidase levels, a lowered number of SiglecFhigh CD11clow eosinophils, and an improved lung PAS score. Furthermore, we observed overexpression of FcγRIIb on the surface of CD19 cells in the lungs of HDM-challenged animals, which negatively correlated with the levels of lung alveolar macrophages, neutrophils, and BALF IL-13. Taken together, these results suggest that the use of FcγRIIb overexpression, combined with the expansion of chimeric protein technology to include more epitopes, could improve the outcome of inflammation.

Recent prevalence of allergic rhinitis caused by house dust mites among the pediatric population in Fukui, Japan

Background

Allergic rhinitis (AR) is an IgE-mediated type I allergic chronic nasal disease common among all age groups, including the pediatric population. House dust mites (HDMs) are globally ubiquitous and the most important indoor aeroallergen. However, the recent prevalence of HDM-caused AR (AR-HDM) in Japan remains unknown, especially after the COVID-19 pandemic.

Objective

The objective of this study was to investigate the current prevalence of AR-HDM, its clinical features, and the current status of medical examinations in elementary school students.

Methods

A survey of 41,000 elementary school students was conducted during July 2021 in Fukui Prefecture, Japan. Parents were asked to complete a questionnaire that examined allergic disease history and clinical background.

Results

A total of 17,974 subjects were analyzed in the study. The results showed that the current prevalence of AR-HDM in elementary school children is 18.8%. We found that AR-HDM had already developed before entrance into elementary school in 68.3% of affected subjects. Among these subjects, 82.3% had received some form of treatment, such as prescription medications, whereas 4.2% were treated by allergen immunotherapy. Multiple logistic regression analysis of the onset of AR-HDM revealed that male sex, being the first-born child, comorbidity of bronchial asthma, atopic dermatitis, food allergy, and allergic conjunctivitis are associated with development of AR-HDM.

Conclusions

The present study revealed the prevalence of AR-HDM in elementary school children. The results emphasize the importance of appropriate diagnosis and treatment from infancy through early childhood.

Accurate determination of house dust mite sensitization in asthma and allergic rhinitis through cytometric detection of Der p 1 and Der p 2 binding on basophils (CytoBas)

BACKGROUND

House dust mite (HDM) is the most common allergen trigger globally for allergic rhinitis and atopic asthma.

OBJECTIVES

To expedite accurate confirmation of allergen sensitization, we designed fluorescent allergen tetramers to directly stain specific IgE on basophils to detect specific allergen sensitization using the flow cytometric CytoBas assay.

METHODS

Recombinant proteins of major HDM allergens (component), Der f 1, Der p 1, and Der p 2 were biotinylated and conjugated with fluorochrome streptavidins as tetramers. Blood samples from 64 patients who are HDM-allergic and 26 controls that are non-HDM-sensitized were incubated with allergen tetramers for evaluation of basophil binding (CytoBas) and activation (BAT) with flow cytometry.

RESULTS

The tetramers effectively bound and activated basophils from patients who are allergic but not from controls who are nonsensitized. CytoBas with Der p 1 as a single allergen had comparable sensitivity and specificity (92% and 100%) to BAT (91% and 100%) in detecting allergen sensitization, as did CytoBas with Der p 2 (95% and 96%) to BAT (95% and 87%). A positive staining for Der p 1 and/or Der p 2 in CytoBas was 100% sensitive and 96% specific for HDM allergy.

CONCLUSIONS

CytoBas has diagnostic accuracy for group 1 and group 2 HDM allergens that is comparable to BAT, but with additional advantages of multiple allergen components in a single tube and no requirement for in vitro basophil activation. These findings endorse a single, multiplex CytoBas assay for accurate and component-resolved diagnosis of aeroallergen sensitization in patients with allergic asthma and/or rhinitis.

Novel monoclonal antibodies against house dust mite allergen Der p 21 and their application to analyze allergen extracts

Background

Allergen extracts and recombinant allergens are used in allergy diagnostics and immunotherapy. Since allergen extracts from different manufacturers lack proper standardization regarding their composition, monoclonal antibodies (MAbs) against specific allergen components can be used for their identification and quantification in allergen extracts. This study aimed to generate MAbs against allergen Der p 21 of Dermatophagoides pteronyssinus for the analysis of allergen extracts.

Methods

Recombinant Der p 21 was expressed in E. coli and purified using affinity chromatography. MAbs against Der p 21 were generated using hybridoma technology. House dust mite (HDM) allergen extracts were analyzed using the newly developed sandwich enzyme-linked immunosorbent assay, Western blotting and microarray immunoassay.

Results

MAbs raised against recombinant Der p 21 were characterized in detail and proven to be reactive with natural Der p 21. Highly specific sandwich enzyme-linked immunosorbent assay for the quantification of Der p 21 was developed and optimized. The allergen was detected and its concentration was determined in only three of six analyzed HDM allergen extracts from different manufacturers.

Conclusion

HDM analysis by MAb-based immunoassays shows their differences in allergen composition. The results demonstrate the importance of allergen-specific MAbs as a tool for the characterization of allergen extracts and the need for their appropriate standardization before their use for allergy diagnostics or immunotherapy.

Natural killer T cells in allergic asthma: implications for the development of novel immunotherapeutical strategies

Allergic asthma has emerged as a prevalent allergic disease worldwide, affecting most prominently both young individuals and lower-income populations in developing and developed countries. To devise effective and curative immunotherapy, it is crucial to comprehend the intricate nature of this condition, characterized by an immune response imbalance that favors a proinflammatory profile orchestrated by diverse subsets of immune cells. Although the involvement of Natural Killer T (NKT) cells in asthma pathology is frequently implied, their specific contributions to disease onset and progression remain incompletely understood. Given their remarkable ability to modulate the immune response through the rapid secretion of various cytokines, NKT cells represent a promising target for the development of effective immunotherapy against allergic asthma. This review provides a comprehensive summary of the current understanding of NKT cells in the context of allergic asthma, along with novel therapeutic approaches that leverage the functional response of these cells.

Sensitization profiles to house dust mite Dermatophagoides pteronyssinus molecular allergens in the Lithuanian population: Understanding allergic sensitization patterns

BACKGROUND

House dust mite (HDM) allergy is a prevalent global health concern, with varying sensitization profiles observed across populations. We aimed to provide a comprehensive assessment of molecular allergen sensitization patterns in the Lithuanian population, with a focus on Dermatophagoides pteronyssinus (Der p), and investigate patterns of concomitant reactivity among different allergens to enhance the accuracy of HDM allergy diagnostics.

METHODS

A comprehensive analysis of 1520 patient test results in Lithuania from 2020 to 2022 was performed. Sensitization patterns to major (Der p 1, Der p 2, and Der p 23) and minor (Der p 5, Der p 7, and Der p 21) Der p allergen components were described using molecular-based diagnostics. Additionally, we investigated sensitization to allergen components from other allergen sources, including tropomyosins (Der p 10, Per a 7, Pen m 1, Ani s 3, Blo t 10) and arginine kinases (Pen m 2, Bla g 9, Der p 20).

RESULTS

This study reveals a high prevalence of HDM sensitization in Lithuania - 481 individuals (45.38% of the sensitized group) exhibited sensitization to at least one Der p allergen component. Importantly, within the sensitized group, 37.21% of patients were sensitized to Der p 5, Der p 7, or Der p 21 in addition to major allergenic components. Distinct sensitization patterns were observed across different age groups, indicating the influence of age-related factors. Furthermore, we confirmed cross-reactivity between Der p 5 and Blo t 5 as well as between Der p 21 and Blo t 21, emphasizing the clinical relevance of these associations. We also highlighted the complexity of sensitization patterns among tropomyosins and arginine kinases.

CONCLUSION

This study provides valuable insights into HDM allergy sensitization profiles in Lithuania, emphasizing the importance of considering major and minor HDM allergen components for accurate diagnosis and management of HDM-related allergic diseases. Differences between populations and age-related factors impact sensitization patterns. Understanding concomitant reactivity among allergens, such as Der p 5 and Blo t 5, Der p 21 and Blo t 21, tropomyosins, and arginine kinases, is crucial for improving diagnostic strategies and developing targeted interventions for allergic individuals.

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.

Comparative analysis of cysteine proteases reveals gene family evolution of the group 1 allergens in astigmatic mites

BACKGROUND

Astigmatic mites contain potent allergens that can trigger IgE-mediated immune responses, leading to allergic diseases such as asthma, allergic rhinitis and atopic dermatitis. In house dust mites Dermatophagoides pteronyssinus and Dermatophagoides farinae, group 1 allergens (Der p 1 and Der f 1), characterized as papain-like cysteine proteases, have been defined as the major allergens that have high prevalence and potency. Previous studies of mite group 1 allergens mainly focused on identification, comparison of sequence and structure, as well as the investigation of cross-reactivity. To achieve a comprehensive view of mite group 1 allergens, we performed a comparative genomic analysis of all the cysteine proteases in six astigmatic mite species to elucidate the evolutionary relationships of group 1 allergens.

METHODS

Based on the high-quality and annotated genomes, all the cysteine proteases in six astigmatic mite species were identified by sequence homology search. The phylogenetic relationships, gene synteny and expression levels were revealed by bioinformatic tools. The allergenicity of recombinant cysteine proteases was evaluated by enzyme-linked immunosorbent assay.

RESULTS

Tandem duplication was revealed as the major feature of cysteine protease gene evolution in astigmatic mites. The high IgE-binding capacity and the significant expression level of the cysteine protease DP_007902.01 suggested its potential as a novel group 1 allergen of D. pteronyssinus. In addition, gene decay events were identified in the skin-burrowing parasitic mite Sarcoptes scabiei.

CONCLUSION

This comprehensive analysis provided insights into the evolution of cysteine proteases, as well as the component-resolved diagnosis of mite allergies.

ATP functions as a primary alarmin in allergen-induced type 2 immunity

Environmental allergens that interact with the airway epithelium can activate cellular stress pathways that lead to the release of danger signals known as alarmins. The mechanisms of alarmin release are distinct from damage-associated molecular patterns (DAMPs), which typically escape from cells after loss of plasma membrane integrity. Oxidative stress represents a form of allergen-induced cellular stress that stimulates oxidant-sensing mechanisms coupled to pathways, which facilitate alarmin mobilization and efflux across the plasma membrane. In this review, we highlight examples of alarmin release and discuss their roles in the initiation of type 2 immunity and allergic airway inflammation. In addition, we discuss the concept of alarmin amplification, where "primary" alarmins, which are directly released in response to a specific cellular stress, stimulate additional signaling pathways that lead to secretion of "secondary" alarmins that include proinflammatory cytokines, such as IL-33, as well as genomic and mitochondrial DNA that coordinate or amplify type 2 immunity. Accordingly, allergen-evoked cellular stress can elicit a hierarchy of alarmin signaling responses from the airway epithelium that trigger local innate immune reactions, impact adaptive immunity, and exacerbate diseases including asthma and other chronic inflammatory conditions that affect airway function.

Blood eosinophil related to maternal allergic rhinitis is associated with the incidence of allergic rhinitis in offspring: COCOA study

OBJECTIVE

The identification of allergic rhinitis (AR) in early life is important for the target of intervention. AR is caused by various environmental factors, including house dust mites. We investigated the relationship between the Dermatophagoides farinae (Der f)-IgE and eosinophil in mothers with AR at delivery and the eosinophil levels and AR incidence in children.

METHODS

The study participants were 983 mother-child pairs from the COhort for Childhood Origin of Asthma and Allergic Diseases. AR was diagnosed by a doctor at delivery in mother and at 3 years of age in offspring. The association between eosinophil level and AR was assessed using logistic regression analysis.

RESULTS

The Der f-IgE level in mother having AR at delivery was associated with the mother's eosinophil level, and the mother's eosinophil level was associated with the child's eosinophil level both at age 1 and 3. The risk of AR at age 3 in children was increased according to increased eosinophil levels in mothers at delivery and in children both aged 1 and 3 years (adjusted odds ratio [aOR] and 95% confidence interval [CI]: 2.57 [1.14-5.78], 2.28 [1.02-5.13], respectively). The risk of childhood AR at the age of 3 is increased when both mothers and children have high eosiniophils (aOR and 95% CI: 2.62 [1.01-6.79], 1.37 [0.98-1.91]).

CONCLUSIONS

Der f-IgE in mothers at delivery was related to eosinophil levels in mothers with AR and higher level of eosinophils in both mother and children was associated with the increased risk of AR incidence at the first 3 years of life of children.

Allergen-specific immunotherapy by recombinant Der P1 allergen-derived peptide-based vaccine in an allergic mouse model

AIM

Increased IgE levels have made house dust mite allergens one of the most frequent causes of allergies worldwide. Treatment reduces the IgE antibodies and types two cytokines, namely interleukin-4 (IL-4) and IL-13. Although existing treatments significantly reduce IgE or IL-4/IL-13, they are very costly. This study aimed to construct a recombinant protein derived from rDer p1 peptides in the form of an immunotherapy approach and to measure the response of IgE and IgG antibodies.

METHODS

The proteins were isolated, purified, and evaluated using the SDS-PAGE and Bradford test and confirmed by using Western blot. To evaluate immunotherapy efficiency, 24 BALB/C mice were sensitized intraperitoneally with house dust mites (HDM) adsorbed to Aluminum hydroxide (Alum) and randomly divided into four groups of six: control sensitized, HDM extract, rDer p1, and DpTTDp vaccine. To immunization, four groups of random mice were each treated with phosphate-buffered saline, 100 μg of rDer p1 protein, DpTTDp, or HDM extract, every 3 days. Direct ELISA determined HDM-specific IgG and IgE subclasses. Data were analyzed in SPSS and Graph pad prism software. Values of p < .05 were considered significant.

RESULTS

After immunization of mice, the rDer P1 and recombinant vaccine like HDM extract increased IgG antibody titer and decreased IgE-dependent reactivity in allergic mice to rDer P1. Also, the levels of inflammatory IL-4 and IL-13 cytokines as allergic stimulants decreased.

CONCLUSION

The use of present available recombinant proteins is considered a viable, cost-effective, and long-term option for providing effective HDM allergy immunotherapy vaccines without side effects.

Allergic rhinitis behavioral changes after Indonesian house dust mites allergenic extract administration as immunotherapy

Background: Allergy is a hypersensitivity reaction that is generally mediated by Immunoglobulin E (IgE). More than 25% of the world’s population is suspected of having these various diseases, and the prevalence and progression of these diseases have continued to increase significantly in recent years. Among these allergy-related diseases, allergic rhinitis and food allergy are the types of allergies with the highest prevalence. Clinical manifestations of allergic rhinitis include sneezing, rhinorrhea, nasal itching, and nasal congestion. Objective: This study aimed to determine the behavioral changes of allergic rhinitis after Indonesian House Dust Mites (IHDM) allergenic extract administration as an immunotherapy. Methods: Eight male BALB/c mice aged 6-8 weeks in each group were treated for seven groups. The sensitization phase is given intraperitoneal, the desensitization phase is given by subcutaneous, and the challenge phase is given intranasal. The allergic parameters were observed, such as nose rubbing and sneezing. The parameters were observed for 15 minutes after the challenge administration. Results: The results showed that the administration of Indonesian House Dust Mites as immunotherapy decreased the frequency of nose rubbing and sneezing after the administration of immunotherapy compared to the allergic rhinitis model. Conclusions: The administration of the Indonesia House Dust Mites as immunotherapy decreased the allergic rhinitis immune response by altering the behavioral parameter.

Co-occurrence of airborne biological and anthropogenic pollutants in the central European urban ecosystem

The interactions between organic and inorganic air pollutants, enhanced by the impact of weather parameters, may worsen the respiratory allergy symptoms in allergy sufferers. Pollen grains and fungal spores belong to some of the most crucial aeroallergens. Other allergenic bioparticles in the atmospheric microbiome can include microalgae, fern spores and mites. In this study, we evaluated if and to what extent air pollutants and weather parameters drive the daily variation in airborne concentrations of broad spectrum of bioparticles (pollen grains, fungal spores, microalgae, fern spores and invertebrates) in the air of Bratislava over 3 years, 2019-2021. Air samples were collected using a Hirst-type volumetric sampler. Based on the results of Spearman's correlation analysis, air temperature seems to be the most influential meteorological factor, positively associated with the concentration of all types of bioparticles at assemblage level, even though the association with microalgae was negative. Wind speed, known to have a diluting effect on most airborne particles, appears to be the most influential for microalgae, as their concentration in the air increases along with rising wind speed. Considering air pollutants, correlation analysis revealed that as the daily concentrations of ozone, PM10, CO and/or NO2 increased, so did the levels of most types of analysed bioaerosols at the assemblage level. Regarding that bioparticles may act as carriers for inorganic particles and amplify their allergenic impact, a concomitant increment in the airborne concentration of both organic and inorganic pollutants poses a threat to allergy sufferers in the study area. The concentration of microalgae, on the other hand, decreases with rising levels of CO, NO2 and PM10; thereby, their synergistic effect on allergy sufferers is negligible. Based on our findings, we suggest that the response of pollen and fungal spore concentration to environmental conditions should be investigated at the taxon, not the assemblage level, as each pollen/spore taxon has a different pattern in response to meteorological parameters and air pollutants.

Determination of immunogenic epitopes in major house dust mite allergen, Der p 2, via nanoallergens

BACKGROUND

Despite the high prevalence of allergic asthma, currently, avoidance of the responsible allergens, which is nearly impossible for allergens such as house dust mite (HDM), remains among the most effective treatment. Consequently, determination of the immunogenic epitopes of allergens will aid in developing a better understanding of the condition for diagnostic and therapeutic purposes. Current methods of epitope identification, however, only evaluate immunoglobulin E-epitope binding interactions, which is not directly related to epitope immunogenicity.

OBJECTIVE

To determine and rank the immunogenicity of the epitopes of major HDM allergen, Der p 2.

METHODS

We performed degranulation assays with RBL-SX38 cells primed using patient plasma and challenged with nanoallergens which multivalently displayed epitopes to study the relative immunogenicity of various epitopes of Der p 2. Nanoallergens were used to evaluate epitopes individually or in combination.

RESULTS

When evaluated using 3 patient samples, 3 epitopes in 2 distal regions of Der p 2 were identified as highly immunogenic when presented in combination, whereas no individual epitope triggered relevant degranulation. One of the epitopes (69-DPNACHYMKCPLVKGQQY-86) was identified to be cooperatively immunogenic when combined with other epitopes.

CONCLUSION

Our study highlights the importance of conformational epitopes in HDM-related allergies. This study also provides further evidence of the versatility of nanoallergens and their value for functional characterization of allergy epitopes, by ranking the Der p 2 epitopes according to immunogenicity. We believe that nanoallergens, by aiding in identification and understanding of immunogenic epitopes, will provide a better understanding of the manifestation of the allergic condition and potentially aid in developing new treatments.

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.

House Dust Mite Precision Allergy Molecular Diagnosis (PAMD@) in the Th2-prone Atopic Dermatitis Endotype

Atopic dermatitis (AD) endotyping might be important for developing personalized diagnostic and therapeutic strategies to the different phenotypes. The current study investigated the IgE molecular profile to Dermatophagoides pteronyssinus (D. pteronyssinus) in a subset of patients afflicted with varying severity stages of atopic dermatitis in a subtropical region subjected to a high perennial house dust mite (HDM) exposure. We selected patients showing a clinically relevant sensitization to HDM with mild-to-moderate and severe AD according to their basal Severity Scoring Atopic Dermatitis (SCORAD) index. Skin prick test (SPT) with standardized mite extracts, as well as a Precision Allergy Molecular Diagnosis (PAMD@) panel including nine different D. pteronyssinus allergens and the related protein allergenic characterization, were assessed in all serum samples. A total of 80 European American AD patients with the marked T2 endotype confirmed their eligibility for the study. Major allergens (Der p 23, Der p 2, and Der p 1) were present in more than 86% of all subjects, with mid-tier allergens (Der p 5, Der p 7, and Der p 21) reaching up to 65%. A serodominant role for Der p 11 could not be quantitatively confirmed in the present cohort. The proposed component resolved diagnosis (CRD) panel appeared to be sufficient to obtain a precise D. pteronyssinus molecular diagnosis in AD patients subjected to a climate-dependent high-mite allergen exposure. The raised seroprevalence of IgE response to Der p 23 confirmed this constituent as a major D. pteronyssinus allergen in severe stages of atopic dermatitis. A clinically driven molecular approach appears to be essential to frame a more precise diagnosis and therapy of this heterogeneous allergic condition.

An Autophagy Modulator Peptide Prevents Lung Function Decrease and Corrects Established Inflammation in Murine Models of Airway Allergy

The involvement of autophagy and its dysfunction in asthma is still poorly documented. By using a murine model of chronic house dust mite (HDM)-induced airway inflammation, we tested the expression of several autophagy markers in the lung and spleen of asthma-like animals. Compared to control mice, in HDM-sensitized and challenged mice, the expression of sequestosome-1/p62, a multifunctional adaptor protein that plays an important role in the autophagy machinery, was raised in the splenocytes. In contrast, its expression was decreased in the neutrophils recovered from the bronchoalveolar fluid, indicating that autophagy was independently regulated in these two compartments. In a strategy of drug repositioning, we treated allergen-sensitized mice with the therapeutic peptide P140 known to target chaperone-mediated autophagy. A single intravenous administration of P140 in these mice resulted in a significant reduction in airway resistance and elastance, and a reduction in the number of neutrophils and eosinophils present in the bronchoalveolar fluid. It corrected the autophagic alteration without showing any suppressive effect in the production of IgG1 and IgE. Collectively, these findings show that autophagy processes are altered in allergic airway inflammation. This cellular pathway may represent a potential therapeutic target for treating selected patients with asthma.

Helminth infection induces non-functional sensitization to house dust mites

BACKGROUND

IgE characterizes the humoral response of allergic sensitization but less is known about what modulates its function and why some patients present clinical symptoms for a given IgE level and others do not. An IgE response also occurs during helminth diseases, independently of allergic symptoms. This response could be a model of non-functional IgE.

OBJECTIVE

To study the IgE response against environmental allergens induced during natural helminth infection.

METHODS

In 28 non allergic subjects from the periphery of Ho Chi Minh city with (H+, n = 18) and without helminth infection (H-, n = 10), we measured IgE and IgG4 against several components of Dermatophagoïdes pteronyssinus (Dpt) and Ascaris (a marker of immunization against nematodes), and determined the IgE component sensitization profile using microarray ISAC biochips. The functional ability of IgE to induce degranulation of cultured mast cells was evaluated in the presence of Dpt.

RESULTS

Non allergic H+ subjects exhibited higher levels of IgE against Dpt compared to H- subjects. Dpt IgE were not functional in vitro and did not recognize usual Dpt major allergens. IgE recognized other component allergens that belong to different protein families, and most were glycosylated. Depletion of IgE recognizing carbohydrate cross-reactive determinant (CCD) did not induce a reduction in Dpt IgE. The Dpt IgG4 were not significantly different.

CONCLUSION

Helminth infections induced IgE against allergens such as Dpt and molecular components that belong to different sources as well as against CCD (such as β-1,2-xylose and/or ⍺-1,3-fucose substituted N-glycans). Dpt IgE were not able to induce degranulation of mast cells and were not explained by sensitization to usual major allergens or N-glycans.

Impact of Probiotic Bacteria on Respiratory Allergy Disorders

Respiratory allergy is a common disease with an increased prevalence worldwide. The effective remedy is still unknown, and a new therapeutic approach is highly desirable. The review elaborates the influence of probiotic bacteria on respiratory allergy prevention and treatment with particular emphasis on the impact of the current methods of their administration – oral and intranasal. The background of the respiratory allergy is complex thus, we focused on the usefulness of probiotics in the alleviation of different allergy factors, in particular involved in pathomechanism, local hypersensitive evidence and the importance of epithelial barrier. In this review, we have shown that (1) probiotic strains may vary in modulatory potential in respiratory allergy, (2) probiotic bacteria are beneficial in oral and intranasal administration, (3) recombinant probiotic bacteria can modulate the course of respiratory allergy.

Management of adult asthma and chronic rhinitis as one airway disease

Introduction: Chronic rhinitis is defined as nasal inflammation with the presence of minimum two symptoms such as nasal obstruction, rhinorrhea, sneezing and/or itching one hour daily for a minimum of 12 weeks/year. According their etiology, four groups of rhinitis are described: allergic, infectious, non-allergic non-infectious and mixed.Chronic rhinitis is frequently associated with asthma, shares similar mechanisms of the pathogenesis and has a negative impact of its outcomes sustaining the concept of unified airways disease.Areas covered: The present review summarizes the complex relationship between chronic rhinitis and asthma on the basis of recent epidemiological data, clinical characteristics, diagnosis and therapeutic management. All four groups are discussed with the impact of their specific treatment on asthma outcomes. Some medications are common for chronic rhinitis and asthma while others are more specific but able to treat the associated comorbidity.Expert opinion: The systematic assessment of chronic rhinitis in patients with asthma and its specific treatment improves both disease outcomes. Conversely, several therapies of asthma demonstrated beneficial effects on chronic rhinitis. Treating both diseases at the same time by only one medication is an interesting option to explore in the future in order to limit drugs administration, related costs and side effects.

Repeated exposure of house dust mite induces progressive airway inflammation in mice: Differential roles of CCL17 and IL-13

We conducted a systematic evaluation of lung inflammation indued by repeated intranasal exposure (for 10 consecutive days) to a human aeroallergen, house dust mite (HDM) in BALB/c mice. Peak influx of neutrophils, monocytes/lymphocytes, and eosinophils was observed in bronchoalveolar lavage (BAL) on days 1, 7 and 11, respectively, and normalized to baseline by day 21. Peak elevations of Th2, myeloid-derived cytokines/chemokines and serum IgE were seen both in BAL and lung tissue homogenates between days 7 and 11, and declined thereafter; however, IL-33 levels remained elevated from day 7 to day 21. Airway hyperreactivity to inhaled methacholine was significantly increased by day 11 and decreased to baseline by day 21. The lung tissue showed perivascular and peribronchial cuffing, epithelial hypertrophy and hyperplasia and goblet cell formation in airways by day 11, and resolution by day 21. Levels of soluble collagen and tissue inhibitors of metalloproteinases (TIMP) also increased reflecting tissue remodeling in the lung. Microarray analysis demonstrated a significant time-dependent up-regulation of several genes including IL-33, CLCA3, CCL17, CD4, CD10, CD27, IL-13, Foxa3, IL-4, IL-10, and CD19, in BAL cells as well as the lung. Pre-treatment of HDM challenged mice with CCL17 and IL-13 antibodies reduced BAL cellularity, airway hyper-responsiveness (AHR), and histopathological changes. Notably, anti-IL-13, but not anti-CCL17 monoclonal antibodies (mAbs) reduced BAL neutrophilia while both mAbs attenuated eosinophilia. These results suggest that CCL17 has an overlapping, yet distinct profile versus IL-13 in the HDM model of pulmonary inflammation and potential for CCL17-based therapeutics in treating Th2 inflammation.

Clinical validation of controlled exposure to house dust mite in the environmental exposure unit (EEU)

Rationale

The Environmental Exposure Unit (EEU), a controlled allergen exposure model of allergic rhinitis (AR), has traditionally utilized seasonal allergens. We sought to clinically validate the use of house dust mite (HDM), a perennial allergen, in the HDM-EEU, a specially designed facility within the larger EEU.

Methods

Forty-four HDM-allergic and eleven non-allergic participants were screened and deemed eligible for one of two 3-h exposure sessions in the HDM-EEU. Participants were exposed to a modest or higher HDM target, with blood and nasal brushing samples collected before and after allergen exposure. Symptomatic data, including Total Nasal Symptom Score (TNSS), Total Ocular Symptom Score (TOSS), Total Rhinoconjunctivitis Symptom Score (TRSS), and Peak Nasal Inspiratory Flow (PNIF) were collected at baseline, every 30 min until 3 h, on an hourly basis for up to 12 h, and at 24 h following the onset of HDM exposure.

Results

The modest and higher HDM target sessions respectively featured cumulative total particle counts of 156,784 and 266,694 particles (2.5–25 µm), Der f 1 concentrations of 2.67 ng/m³ and 3.80 ng/m³, and Der p 1 concentrations of 2.07 ng/m³ and 6.66 ng/m³. Allergic participants experienced an increase in symptoms, with modest target participants plateauing at 1.5 to 2 h and achieving a mean peak TNSS of 5.74 ± 0.65, mean peak TOSS of 2.47 ± 0.56, and mean peak TRSS of 9.16 ± 1.32. High HDM-target allergics reached a mean peak TNSS of 8.17 ± 0.71, mean peak TOSS of 4.46 ± 0.62, and mean peak TRSS of 14.08 ± 1.30 at 3 h. All allergic participants’ symptoms decreased but remained higher than baseline after exiting the HDM-EEU. Sixteen participants (37.2%) were classified as Early Phase Responders (EPR), eleven (25.6%) as protracted EPR (pEPR), seven (16.3%) as Dual Phase Responders (DPR), and nine (20.9%) as Poor Responders (PR). Allergic participants experienced significant percent PNIF reductions at hours 2 and 3 compared to healthy controls. Non-allergics were asymptomatic during the study period.

Conclusions

The HDM-EEU is an appropriate model to study HDM-induced AR as it can generate clinically relevant AR symptoms amongst HDM-allergic individuals.

The role of house dust mite immunotherapy in Indonesian children with chronic rhinosinusitis allergy: A randomized control trial

Background

Chronic rhinosinusitis allergy (CRA) is a disease that is commonly found in children and is mostly caused by allergy to house dust mites (HDM). The use of HDM immunotherapy can be considered in children with allergies.

Objectives

Analyzing the impact of mite immunotherapy on disease burden in Indonesian children with CRA.

Methods

A randomized control trial study was conducted to participants in 2 groups, namely the immunotherapy group (n = 25) and the non-immunotherapy group (n = 25). Participants were given HDM immunotherapy for 14 weeks, which was given once per week. Participants during therapy were evaluated for rhinosinusitis symptoms and measured their immunity status (specific IgE), sleep quality (SDSC), quality of life (SN5), and family coping (F-COPES) pre-post therapy. Statistical analysis used in this study included paired t-test, Wilcoxon test, independent t-test, or Mann Whitney test with p < 0.05.

Results

The value of specific IgE in the immunotherapy group was 4.12 ± 7.75 kU/l (pre-test) and 1.52 ± 2.42 kU/l (post-test; p < 0.001), while in the non-immunotherapy group was 1.47 ± 3.28 kU/l (pre-test) and 1.18 ± 2.81 kU/l (post-test; p = 0.317). The SDSC value in the immunotherapy group was 42.16 ± 2.75 (pre-test) and 30.32 ± 3.22 (post-test; p < 0.001), while in the non-immunotherapy group was 41.92 ± 2.75 (pre-test) and 41.84 ± 2.87 (post-test; p = 0.987). The F-COPES value in the immunotherapy group was 101.56 ± 5.78 (pre-test) and 105.20 ± 4.31 (post-test; p = 0.015), while in the non-immunotherapy group was 100.36 ± 9.63 (pre-test) and 99.96 ± 9.98 (post-test; p = 0.224). The SN-5 value in the immunotherapy group was 30.04 ± 2.78 (pre-test) and 11.00 ± 2.33 (post-test; p < 0.001), while in the non-immunotherapy group was 30.04 ± 2.78 (pre-test) and 30.04 ± 2.78 (post-test; p = 0.767). There was a significant comparison between the immunotherapy group and the non-immunotherapy group on the specific IgE (p = 0.013), SDSC (p < 0.001), and SN-5 (p < 0.001) values. Meanwhile, there was no significant difference in the F-COPES value (p = 0.129).

Conclusions

The administration of HDM immunotherapy can improve the participant's immunity, quality of life, and sleep disorder.

Manifesto on united airways diseases (UAD): an Interasma (global asthma association - GAA) document

OBJECTIVE

The large amount of evidence and the renewed interest in upper and lower airways involvement in infectious and inflammatory diseases has led Interasma (Global Asthma Association) to take a position on United Airways Diseases (UAD).

METHODS

Starting from an extensive literature review, Interasma executive committee discussed and approved this Manifesto developed by Interasma scientific network (INES) members.

RESULTS

The manifesto describes the evidence gathered to date and defines, states, advocates, and proposes issues on UAD (rhinitis, rhinosinusitis and nasal polyposis), and concomitant/comorbid lower airways disorders (asthma, chronic obstructive pulmonary disease, bronchiectasis, cystic fibrosis, obstructive sleep apnoea) with the aim of challenging assumptions, fostering commitment, and bringing about change. UAD refers to clinical pictures characterized by the coexistence of upper and lower airways involvement, driven by a common pathophysiological mechanism, leading to a greater burden on patient's health status and requiring an integrated diagnostic and therapeutic plan. The high prevalence of UAD must be taken into account. Upper and lower airways diseases influence disease control and patient's quality of life.

CONCLUSIONS

Patients with UAD need to have a timely and adequate diagnosis, treatment, and, when recommended, referral for management in a specialized center. Diagnostic testing including skin prick or serum specific IgE, lung function, fractional exhaled nitric oxide (FeNO), polysomnography, allergen-specific immunotherapies, biological therapies and home based continuous positive airway pressure (CPAP) whenever these are recommended, should be part of the management plan for UAD. Education of medical students, physicians, health professionals, patients and caregivers on the UAD is needed.

Proteomic profiling of commercial dust mite skin prick test solutions and allergy vaccines from India

BACKGROUND

Skin prick test (SPT) solutions and allergy vaccines (AVs) are crucial tools for diagnosis and therapy of allergies. It was the aim of this study to corroborate the content of products for diagnosis and treatment of dust mite allergies that are produced and sold in India.

METHODS

SDS-PAGE, immunoblots and high-resolution mass spectrometric analysis was performed with 16 house dust mite (HDM) SPT solutions and AVs from 3 Indian manufacturers. Authority-approved European SPT solutions and in-house extracts were used as references.

RESULTS

From the 5 Indian Dermatophagoides pteronyssinus products, none contained proteins from this source. Instead, 1 sample contained Dermatophagoides farinae and human serum proteins, 4 products contained allergens from the storage mite Suidasia medanensis, allergens from the legume Cicer arietinum (chickpea), and proteins from baker's yeast. From 4 Indian D. farinae-labeled products, 2 contained human serum proteins and a limited number of D. farinae allergens. Two contained only Suidasia, Cicer, and yeast proteins. In contrast, the European authority-approved D. pteronyssinus and D. farinae SPT solutions that were used as reference in this study, contained exclusively proteins of the respective species and covered the expected allergen spectra. The Blomia tropicalis sample contained no Blomia allergens at all, but consisted exclusively of Suidasia, Cicer, and yeast proteins. All 6 HDM samples consisted of human serum proteins and limited amounts of D. farinae allergens.

CONCLUSIONS

All commercial Indian SPT solutions and AVs analyzed in this study are not suitable for dust mite allergy diagnosis and therapy, as they contain either no, or only a limited number of, HDM allergens. In addition, their use could lead to misdiagnosis since some of them contain allergens from other sources, including the storage mite Suidasia, chickpea, as well as baker's yeast. Further, their application might be harmful to patients, as some products contain large amounts of proteins of human origin. Analysis of European SPT solutions, on the other hand, confirmed their suitability for dust mite allergy diagnosis.

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.

TRPV4-Mediated Epithelial Junction Disruption in Allergic Rhinitis Triggered by House Dust Mites

BACKGROUND

Epithelial barrier disruption is a crucial feature of allergic rhinitis (AR). Previous reports have indicated the role of transient receptor potential vanilloid (TRPV) 4 in regulating the intercellular junctions in various cells. However, the role of TRPV4 and its regulation by T helper 2 cell cytokines in the epithelial cells of patients with AR remains unclear.

OBJECTIVE

We aimed to elucidate the expression of TRPV4 in nasal epithelial cells and its cytokine-induced regulation, and to reveal its role in house dust mite-induced junction disruption in AR.

METHODS

The expression of TRPV4 in nasal epithelial cells was measured using real-time polymerase chain reaction, western blot, and immunohistochemical assays, and the expression levels were compared between the patients with AR and healthy controls. Altered expression of TRPV4 was induced in cultured nasal epithelial cells by stimulation of interleukin (IL) 4, IL-13, and tumor necrosis factor alpha. In addition, expression of E-cadherin and zonula occludens 1 was induced in Der p 1-stimulated epithelial cells by treatment with either a TRPV4 agonist (GSK1016790A) or a TRPV4 antagonist (RN1734).

RESULTS

TRPV4 expression was increased in epithelial cells harvested from the affected turbinates compared to those from the normal turbinates. The stimulation of cultured epithelial cells with IL-4 and IL-13 resulted in TRPV4 upregulation. Additionally, E-cadherin and zonula occludens 1 expression levels decreased in the cultured epithelial cells treated with GSK1016790A after stimulation with Der p 1, whereas Der p 1 stimulation alone showed no effect on junctional protein expression.

CONCLUSIONS

Increased TRPV4 expression occurred in epithelial cells harvested from patients with AR and epithelial cells stimulated by Th2 cytokines. Decreased junctional protein expression in epithelial cells after the stimulation by house dust mite allergen with TRPV4 agonist indicates a possible role of TRPV4 in the pathogenesis of allergen-induced epithelial barrier disruption in AR.

Mite Molecular Profile in the Th2-Polarized Moderate-to-Severe Persistent Asthma Endotype Subjected to High Allergen Exposure

BACKGROUND

The association among the IgE responses to prevailing groups of house dust mite (HDM) allergens in the concurrent asthma phenotypes has not been determined.

OBJECTIVE

The aim of the present study lays on a component-resolved diagnosis (CRD) model to investigate the mite molecular signature in subjects with type-2 inflammation asthma.

METHODS

We selected patients showing a clinically relevant sensitization to HDMs with moderate-to-severe persistent asthma. Skin prick test (SPT) with standardized mite extracts, a broad customized CRD serum sIgE panel including 9 Dermatophagoides pteronyssinus allergens and the related protein allergenic characterization, was investigated in all serum samples.

RESULTS

Ninety out of 93 (96.77%) patients with a positive SPT to HDM showed a concordant sIgE (≥0.35 kUA/L) to the crude extract of D. pteronyssinus. Major allergens (Der p 2, Der p 23, and Der p 1) were present in >70% of all subjects, with mid-tier allergens (Der p 5, Der p 7, and Der p 21) reaching up to 51% in the present cohort. A complex pleomorphic repertoire of HDM molecules recognized by IgE was depicted, including 38 distinct profiles.

CONCLUSIONS AND CLINICAL RELEVANCE

The proposed CRD panel approach, containing the most prevalent HDM allergens, appeared to be sufficient to obtain a precise D. pteronyssinus molecular diagnosis in asthmatics with a climate-dependent high-mite allergen exposure and coexisting sensitization. A dominant role of both major and mid-tier allergens has been confirmed in moderate and severe persistent asthmatics with the preponderant Th2-high endotype.

A 300 IR sublingual tablet is an effective, safe treatment for house dust mite-induced allergic rhinitis: An international, double-blind, placebo-controlled, randomized phase III clinical trial

BACKGROUND

Allergic rhinitis induced by house dust mites (HDMs) is a highly prevalent but often underdiagnosed and undertreated/untreated chronic disease. It often has a negative impact on sleep, work, leisure activities, and health-related quality of life. Allergen immunotherapy is a proven, safe treatment for respiratory allergies.

OBJECTIVE

We sought to assess the efficacy and safety of a 300 index of reactivity (IR) sublingual tablet formulation of Dermatophagoides pteronyssinus:Dermatophagoides farinae 1:1 extract in adolescents (aged ≥12) and adults with moderate to severe HDM-induced allergic rhinitis.

METHODS

In a phase III, international, double-blind, placebo-controlled, randomized clinical trial, participants received approximately 12 months of treatment with placebo or the 300 IR tablet. The primary end point was the average total combined score during 4 weeks at the end of the treatment period.

RESULTS

A total of 1607 participants were randomized, and 1476 (including 555 [37.6%] with concomitant mild controlled asthma at inclusion) comprised the full analysis set. Over the primary evaluation period, the least squares mean average total combined score in the 300 IR group (3.62) was significantly lower (P < .0001) than in the placebo group (4.35), with a relative least squares mean difference of -16.9% (95% CI, -24.0% to -9.2%). All prespecified secondary end points were consistently improved in the 300 IR group, relative to placebo. The 300 IR tablet was generally well tolerated. Treatment-related adverse events (mainly mild or moderate local reactions) were reported for 51.0% of the patients in the 300 IR group and 14.9% in the placebo group.

CONCLUSIONS

The 300 IR sublingual HDM tablet is an effective, safe treatment for HDM-induced allergic rhinitis.

Adjuvanting Allergen Extracts for Sublingual Immunotherapy: Calcitriol Downregulates CXCL8 Production in Primary Sublingual Epithelial Cells

Application of allergens onto the sublingual epithelium is used to desensitize allergic individuals, a treatment known as sublingual immunotherapy. However, the response of sublingual epithelial cells to house dust mite allergen and potential tolerance-promoting adjuvants such as Toll-like receptor (TLR) ligands and calcitriol has not been investigated. In order to study this, primary sublingual epithelial cells were isolated from dogs and cultured in vitro. After 24-h incubation with a Dermatophagoides farinae extract, a Dermatophagoides pteronyssinus extract, TLR2 ligands (FSL-1, heat-killed Listeria monocytogenes, Pam3CSK4), a TLR3 ligand (poly I:C), a TLR4 ligand [lipopolysaccharide (LPS)], and calcitriol (1,25-dihydroxyvitamin D₃), viability of the cells was analyzed using an MTT test, and their secretion of interleukin 6 (IL-6), IL-10, CXCL8, and transforming growth factor β1 (TGF-β1) was measured by enzyme-linked immunosorbent assay. Additionally, to evaluate its potential effect as an adjuvant, sublingual epithelial cells were incubated with calcitriol in combination with a D. farinae extract followed by measurement of CXCL8 secretion. Furthermore, the effect of D. farinae and calcitriol on the transcriptome was assessed by RNA sequencing. The viability of the sublingual epithelial cells was significantly decreased by poly I:C, but not by the other stimuli. CXCL8 secretion was significantly increased by D. farinae extract and all TLR ligands apart from LPS. Calcitriol significantly decreased CXCL8 secretion, and coadministration with D. farinae extract reduced CXCL8 concentrations to levels seen in unstimulated sublingual epithelial cells. Although detectable, TGF-β1 secretion could not be modulated by any of the stimuli. Interleukin 6 and IL-10 could not be detected at the protein or at the mRNA level. It can be concluded that a D. farinae extract and TLR ligands augment the secretion of the proinflammatory chemokine CXCL8, which might interfere with sublingual desensitization. On the other hand, CXCL8 secretion was reduced by coapplication of calcitriol and a D. farinae extract. Calcitriol therefore seems to be a suitable candidate to be used as adjuvant during sublingual immunotherapy.

Laser-facilitated epicutaneous immunotherapy with depigmented house dust mite extract alleviates allergic responses in a mouse model of allergic lung inflammation

BACKGROUND

Skin-based immunotherapy of type 1 allergies has recently been re-investigated as an alternative for subcutaneous injections. In the current study, we employed a mouse model of house dust mite (HDM)-induced lung inflammation to explore the potential of laser-facilitated epicutaneous allergen-specific treatment.

METHODS

Mice were sensitized against native Dermatophagoides pteronyssinus extract and repeatedly treated by application of depigmented D pteronyssinus extract via laser-generated skin micropores or by subcutaneous injection with or without alum. Following aerosol challenges, lung function was determined by whole-body plethysmography and bronchoalveolar lavage fluid was analyzed for cellular composition and cytokine levels. HDM-specific IgG subclass antibodies were determined by ELISA. Serum as well as cell-bound IgE was measured by ELISA, rat basophil leukemia cell assay, and ex vivo using a basophil activation test, respectively. Cultured lymphocytes were analyzed for cytokine secretion profiles and cellular polarization by flow cytometry.

RESULTS

Immunization of mice by subcutaneous injection or epicutaneous laser microporation induced comparable IgG antibody levels, but the latter preferentially induced regulatory T cells and in general downregulated T cell cytokine production. This effect was found to be a result of the laser treatment itself, independent from extract application. Epicutaneous treatment of sensitized animals led to induction of blocking IgG, and improvement of lung function, superior compared to the effects of subcutaneous therapy. During the whole therapy schedule, no local or systemic side effects occurred.

CONCLUSION

Allergen-specific immunotherapy with depigmented HDM extract via laser-generated skin micropores offers a safe and effective treatment option for HDM-induced allergy and lung inflammation.

Investigation of house dust mite induced allergy using logistic regression in West Bengal, India

BACKGROUND

The diagnosis of house dust mite (HDM) allergy based on Skin prick test (SPT) is not accurate, especially in lower risk cases. Our aim is to develop and validate a predictive model to diagnose the HDM allergic symptoms (urticaria, allergic rhinitis, asthma).

METHODS

A forward-step logistic regression model was developed using a data set of 537 patients of West Bengal, India consisting of clinical variables (SPT based on 6 allergens of house dust and house dust mites, total IgE) and demographic characteristics (age, sex, house conditions). The output probability was estimated from the allergic symptoms shown by the patients. We finally prospectively validated a data set of 600 patients.

RESULTS

The gradual inclusion of the variables increased the correlation between observed and predicted probabilities (correlation coefficient (r2) = 0.97). The model development using group-1 showed an accuracy rate of 99%, sensitivity and specificity of 99.7% and 88.6% respectively and the area under the receiver operating characteristics (ROC) curve (AUC) of 99%. The corresponding numbers for the validation of our model with group-2 were 87%, 95.6% and 66% and 86% respectively. The model predicted the probability of symptoms better than SPTs in combination (accuracy rate 0.76-0.80), especially in lower risk cases (probability< 0.8) that are highly difficult to diagnose.

CONCLUSION

This is perhaps the first attempt to model the outcome of HDM allergy in terms of symptoms, which could open up an alternative but highly efficient way for accurate diagnosis of HDM allergy enhancing the efficiency of immunotherapy.

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.

Efficacy and safety of sublingual dust mite drops in children with mono- or polysensitized allergic rhinitis

OBJECTIVE

To explore the efficacy and safety of sublingual house dust mite (HDM) drops in children with mono- or polysensitized allergic rhinitis.

METHODS

We conducted a retrospective cohort study of 65 children with monosensitized AR and 118 children with polysensitized AR who were scheduled for sublingual administration of HDM drops from January 2015 to June 2016. Interleukin (IL)-2, IL-4, and IL-17α, transforming growth factor-β1 (TGF-β1), specific immunoglobulin E (IgE), and specific IgG4 were detected by ELISA. The efficacies were assessed using symptoms score and medication score. All the outcomes were measured 1 month before the study and 1 month after the end of the 2-year treatment.

RESULTS

The total nasal symptoms score (TNSS) decreased significantly from 11.27 (9.81 ± 12.73) at baseline to 3.48(1.98 ± 4.98) at the end of sublingual treatment for the monosensitized AP group (t = 30.00, P < 0.01), and from 11.54(10.04 ± 13.04) to 3.56 (2.00 ± 5.16) for the polysensitized AR group (t = 40.05, P < 0.01), respectively. IL-2 and TGF-β1 increased significantly after treatment in contrast with before treatment in both the monosensitized group and the polysensitized group (both P < 0.01). In contrast, IL-4 and IL-17α decreased significantly after treatment compared with the baseline in both groups (both P < 0.01). Sublingual HDM drops were generally safe and well tolerant in both groups.

CONCLUSIONS

This study confirmed the efficacy and safety of sublingual AIT in both monosensitized and polysensitized AR patients (Chinese children).

Ablation of RhoA impairs Th17 cell differentiation and alleviates house dust mite-triggered allergic airway inflammation

Asthma is a heterogeneous chronic airway inflammation in which Th2 and Th17 cells are key players in its pathogenesis. We have reported that RhoA of Rho GTPases orchestrated glycolysis for Th2 cell differentiation and allergic airway inflammation by the use of a conditional RhoA-deficient mouse line. However, the role of RhoA in Th17 cells remains to be elucidated. In this study, we investigated the effects of RhoA deficiency on Th17 cells in the context of ex vivo cell culture systems and an in vivo house dust mites (HDM)-induced allergic airway inflammation. We found that RhoA deficiency inhibited Th17 differentiation and effector cytokine secretion, which was associated with the downregulations of Stat3 and Rorγt, key Th17 transcription factors. Furthermore, loss of RhoA markedly suppressed Th17 and neutrophil-involved airway inflammation induced by HDM in mice. The infiltrating inflammatory cells in the lungs and bronchoalveolar lavage (BAL) fluids were dramatically reduced in conditional RhoA-deficient mice. Th17 as well as Th2 effector cytokines were suppressed in the airways at both protein and mRNA levels. Interestingly, Y16, a specific RhoA inhibitor, was able to recapitulate the most phenotypes of RhoA genetic deletion in Th17 differentiation and allergic airway inflammation. Our data demonstrate that RhoA is a key regulator of Th17 cell differentiation and function. RhoA might serve as a potential novel therapeutic target for asthma and other inflammatory disorders.

Identification of immunodominant IgE binding epitopes of Der p 24, a major allergen of Dermatophagoides pteronyssinus

Background

The identification of house dust mite (HDM) allergens and epitopes is important for allergy diagnosis and treatment. We sought to identify the Dermatophagoides pteronyssinus group 24 allergen (Der p 24) and to identify its immunodominant IgE epitope(s).

Methods

Der p 24 cDNA was cloned and expressed in a pET expression system. The IgE binding activity of purified recombinant (r)Der p 24 was evaluated by western blotting. Truncated Der p 24 proteins and overlapping synthetic polypeptides were subjected to IgE binding assays. Balb/c mice were immunized to investigate IgE epitope induction of IgE production. IgE binding of the 32 N-terminal residues of Der p 24 was compared to other Der p epitopes in enzyme-linked immunosorbent assays and dot blot assays. Human skin prick tests (SPTs) were performed.

Results

We cloned and expressed Der p 24 cDNA (GenBank accession no. KP893174.1). HDM allergic sera bound rDer p 24 in vitro and 5/10 HDM allergic patients (50%) had positive SPT reactions to rDer p 24. The immunodominant IgE epitope of Der p 24 was localized to the N-terminal 32-residue region, which produced a high specific IgE antibody titer in vivo and promoted mast cell β-hexosaminidase release. The IgE binding activity this N-terminal epitope of Der p 24 was stronger than that of Der p 1 or Der p 2 IgE epitopes.

Conclusions

We identified Der p 24 as a major HDM allergen with strong IgE binding activity via an immunodominant IgE epitope in the N-terminal 32-residue region, which triggers IgE production in vivo. The identified Der p 24 epitope may support HDM allergy diagnosis and treatment.

Conjugated bile acids attenuate allergen-induced airway inflammation and hyperresponsiveness by inhibiting UPR transducers

Conjugated bile acids (CBAs), such as tauroursodeoxycholic acid (TUDCA), are known to resolve the inflammatory and unfolded protein response (UPR) in inflammatory diseases, such as asthma. Whether CBAs exert their beneficial effects on allergic airway responses via 1 arm or several arms of the UPR, or alternatively through the signaling pathways for conserved bile acid receptor, remains largely unknown. We used a house dust mite-induced (HDM-induced) murine model of asthma to evaluate and compare the effects of 5 CBAs and 1 unconjugated bile acid in attenuating allergen-induced UPR and airway responses. Expression of UPR-associated transcripts was assessed in airway brushings from human patients with asthma and healthy subjects. Here we show that CBAs, such as alanyl β-muricholic acid (AβM) and TUDCA, significantly decreased inflammatory, immune, and cytokine responses; mucus metaplasia; and airway hyperresponsiveness, as compared with other CBAs in a model of allergic airway disease. CBAs predominantly bind to activating transcription factor 6α (ATF6α) compared with the other canonical transducers of the UPR, subsequently decreasing allergen-induced UPR activation and resolving allergic airway disease, without significant activation of the bile acid receptors. TUDCA and AβM also attenuated other HDM-induced ER stress markers in the lungs of allergic mice. Quantitative mRNA analysis of airway epithelial brushings from human subjects demonstrated that several ATF6α-related transcripts were significantly upregulated in patients with asthma compared with healthy subjects. Collectively, these results demonstrate that CBA-based therapy potently inhibits the allergen-induced UPR and allergic airway disease in mice via preferential binding of the canonical transducer of the UPR, ATF6α. These results potentially suggest a novel avenue to treat allergic asthma using select CBAs.

Validation of PROTIA™ Allergy-Q 64 Atopy® as a Specific IgE Measurement Assay for 10 Major Allergen Components

PURPOSE

Component-resolved diagnostics (CRD) is expected to provide additional diagnostic information in allergic patients. PROTIA™ Allergy-Q 64 Atopy®, a recently developed CRD-based multiplex specific immunoglobulin E (sIgE) assay, can quantitatively measure sIgE to major allergen components.

METHODS

The sIgE detection by PROTIA™ Allergy-Q 64 Atopy® and ImmunoCAP® assays was compared using the sera of 125 Korean allergic patients. Group 1 and 2 allergens of house dust mites (HDMs; Dermatophagoides farinae (Der f) 1 and Der f 2 in PROTIA™ Allergy-Q 64 Atopy®, Dermatophagoides pteronyssinus (Der p) 1 and Der p 2 in ImmunoCAP®), Bet v 1, Fel d 1, Que a 1, ω-5 gliadin, α-lactalbumin, β-lactoglobulin, casein and α-Gal were measured by both assays.

RESULTS

Comparing the results from the 2 assays, the agreement rate for all the 10 allergens was > 88% (group 1 HDM allergen, 100%; group 2 HDM allergen, 94.6%; Bet v 1, 97.4%; Fel d 1, 90.5%; Que a 1, 89.2%; α-lactalbumin, 96%; β-lactoglobulin, 88%; casein, 88%; ω-5 gliadin, 96%; α-Gal, 100%). Correlation analysis indicated that, all the 10 allergen sIgEs showed more than moderate positive correlation (Pearson correlation coefficients > 0.640). Additionally, intra-class comparison showed more than high correlation for all the 10 allergens (Spearman's rank correlation coefficients > 0.743).

CONCLUSIONS

PROTIA™ Allergy-Q 64 Atopy® is reliable and comparable to the ImmunoCAP® assay for component-resolved diagnosis.

Validation of Patient-Reported Outcomes for Clinical Trials in Allergic Rhinitis: A Systematic Review

Although regulatory authorities have recently recommended the use of a combined symptom-medication score as a primary efficacy end point, none has been psychometrically validated. Here, we sought to determine to what extent allergic rhinitis (AR)-related patient-reported outcomes (symptom scores, medication scores, disease control scores, and satisfaction or quality-of-life scales) have been assessed for construct, content, and/or criterion validity, reliability, responsiveness, and the minimal clinically important difference. We searched the PubMed database from January 1997 to June 2018 with logical combinations of key words related to validation, AR, and patient-rated outcomes and scales. From a total of 1705 potentially relevant publications, 55 were reviewed. Despite the current emphasis on a combined symptom-medication score for evaluating the efficacy of allergen immunotherapy in AR, symptom scores have not been extensively validated, and we did not find any publications describing the validation of a medication score. Disease control scales (mainly the Rhinitis Control Assessment Test, the Control of Allergic Rhinitis and Asthma Test, and the Allergic Rhinitis Control Test) and health-related quality-of-life scales (mainly the Rhinoconjunctivitis Quality of Life Questionnaire [RQLQ] and the mini-RQLQ) have been extensively validated in AR but have some practical disadvantages as primary efficacy criteria in clinical trials.

Newly designed hemagglutinin-Der p 2 chimera is a potential candidate for allergen specific immunotherapy

Aim To investigate the immunomodulatory potential of a chimera composed of the receptor-binding domain of hemagglutinin 1 (H1s) from Influenza virus and Der p 2 (D2) allergen for allergen-specific immunotherapy of house-dust mite allergy (HDM).

MAIN METHODS

H1sD2 chimera and D2 allergen were produced by genetic engineering in E. coli. Recombinant antigens were extracted from inclusion bodies by urea, then refolded and purified by immobilized- metal affinity chromatography (IMAC). Purity was verified by 2D-PAGE and secondary structures were assessed by CD spectroscopy. IgE reactivity of H1sD2 and D2 was tested in western blot with sera from 8 persons with clinical history of HDM allergy. Immunogenicity of H1sD2 and D2 were analyzed in Balb/c mice. Cytokine profile was analyzed by ELISA after stimulation of mouse spleen cells with H1sD2 and D2. Leukocyte population abundance of cells isolated from spleen and lymph node was assessed by flow cytometry.

KEY FINDINGS

Purified recombinant proteins H1sD2 (42 kDa) and D2 (15 kDa) revealed well defined secondary structures, and preserved IgE reactive epitopes. Analysis of supernatants of mouse spleen cells after stimulation with H1sD2 and D2, revealed a qualitatively different cytokine profile from H1sD2 immunized mouse cells (increase in IL10). CD8+ cells were decreased in the lymph node of D2 immunized mice, whereas H1sD2 immunization led to an increase of CD8+ cells in both the lymph node and the spleen.

SIGNIFICANCE

H1sD2 chimera attenuates Der p 2-inherent Th2 response and directs the immune response toward Th1 and Treg phenotype.

Bedroom Allergen Exposure Beyond House Dust Mites

PURPOSE OF REVIEW

The review provides insight into recent findings on bedroom allergen exposures, primarily focusing on pet, pest, and fungal exposures.

RECENT FINDINGS

Large-scale studies and improved exposure assessment technologies, including measurement of airborne allergens and of multiple allergens simultaneously, have extended our understanding of indoor allergen exposures and their impact on allergic disease. Practical, streamlined methods for exposure reduction have shown promise in some settings, and potential protective effects of early-life exposures have been further elucidated through the investigation of specific bacterial taxa. Advances in molecular allergology have yielded novel data on sensitization profiles and cross-reactivity. The role of indoor allergen exposures in allergic disease is complex and remains incompletely understood. Advancing our knowledge of various co-exposures, including the environmental and host microbiome, that interact with allergens in early life will be crucial for the development of efficacious interventions to reduce the substantial economic and social burden of allergic diseases including asthma.