Dust Mite Allergen Research Articles

Seroprevalence of Dermatophagoides farinae-specific IgE in dogs with atopic dermatitis in São Paulo, Brazil

Canine atopic dermatitis (CAD) is a chronic, inflammatory, and pruritic disease of the skin resulting from the loss of the epidermal barrier, sensitization, and exacerbated production of IgE antibodies mainly directed against environmental allergens, especially to house dust mites. To select specific allergen immunotherapies with high efficacy, there are necessary studies with house dust mite allergens to improve both serological and intradermal tests. Therefore, the objective of this study was to evaluate the seroprevalence of IgE against Der f 2, Zen 1, and crude Dermatophagoides farinae allergens in dogs with AD in the State of São Paulo, Brazil. The sera of 85 dogs with clinically confirmed atopic dermatitis from the State of São Paulo (Brazil) was collected. In addition, an indirect ELISA test was conducted to detect allergen-specific serum IgE. IgE seropositivity was observed in 97.5% of the dogs for Der f 2, 95.0% for Zen 1, and 92.5% for the crude mite allergens. Due to this high prevalence of IgE specific to these allergens, we suggest that Der f 2 and Zen 1 can be considered major allergens for dogs in the State of São Paulo.

The efficacy and safety of standardized dust mite allergen subcutaneous immunotherapy in children with allergic rhinitis during treatment

Objective: To evaluate the efficacy and safety of standardized dust mite allergen subcutaneous immunotherapy (SCIT) in children with allergic rhinitis (AR) during treatment. Methods: A total of 283 children with AR diagnosed with definite dust mite allergy and completed 2 to 3 years of SCIT who attended the Department of Otorhinolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, from August 2019 to October 2021 were included, including 205 males and 78 females, with a mean age of 10.8 years. The total nasal symptoms score (TNSS), symptom medication score (SMS), rhinoconjunctivitis quality of life questionnaire (RQLQ) and visual analogue scale (VAS) before and after 2 to 3 years' treatment were recorded, and the differences before and after treatment were compared. Adverse reactions during SCIT were recorded to evaluate its safety. SPSS 22.0 software was used for statistical analysis. Results: The overall effectiveness rate during SCIT in 283 children with AR was 89.4% (253/283). Compared with baseline, all symptom scores, medication scores and quality of life scores were significantly lower after 2 to 3 years of SCIT (all P<0.05). Further group comparisons showed positive efficacy in patients with different clinical characteristics, including age, gender, smoking status, family history of AR, symptom severity, mono-or poly-allergy, and second immunization, with no statistically significant differences between groups (all P>0.05). A total of 12 735 injections were administered during the SCIT, and a total of 213 (1.67%) injections of local adverse reactions occurred, mainly in the initial treatment phase, and the diameter of the local air mass was mostly 5 to 20 mm; 71 (0.56%) injections of systemic adverse reactions occurred, mainly in the initial treatment phase, and most of them were grade 1 reactions with no serious systemic adverse reaction such as shock. Conclusion: Standardized dust mite SCIT has a good safety profile and definite efficacy in treating AR children with different clinical characteristics. It can significantly improve all symptoms, reduce the use of symptomatic drugs and improve their quality of life.

Aeroallergen Avoidance: Updated Evidence and How to Advise Patients

Allergic rhinitis (AR) is highly prevalent in Canada, affecting approximately 20–25% of the population. Asthma is estimated to affect approximately three million Canadians, and between 12% and 25% of Canadian children. Approximately two-thirds of individuals with asthma are allergic to aeroallergens, and these allergens act as triggers for asthma exacerbations. Overall, approximately 7.7 million individuals were affected by aeroallergens in Canada in 2016. High concentrations of ambient aeroallergens, including tree pollen and fungal spores have been associated with increased risk of premature birth, myocardial infarction (MI) and asthma-related Emergency Department visits and hospitalizations in cities across Canada. This demonstrates that nation-wide aeroallergen counts are associated with severe signs and symptoms. Children exposed to various indoor allergens are placed at an increased risk of developing asthma in later life, with sensitization in these individuals being a strong predictor of disease morbidity. Common indoor exposures for infants include house dust mite, pet, cockroach, mould, and rodent allergens. Sensitization to at least one indoor allergen has been demonstrated to be present in nine of every ten children hospitalized with asthma. It has been noted that more than 90% of children worldwide breathe polluted air. While the impact of climate change on aeroallergen exposure is not fully understood, there is increasing evidence that it may have an impact on outdoor aeroallergens and, by extension, asthma control in children. Global warming has been projected to influence the duration and intensity of pollen seasons, and may lead to increased pollen production, prolonged pollen seasons, and increased pollen protein allergenicity. The changing weather patterns including rainfall and wind may cause pollen species to reach environments in which they had not previously been present, contributing to a shift in geographic pollen distributions.

TNF-like weak inducer of apoptosis inhibition is comparable to IL-13 blockade in ameliorating atopic dermatitis inflammation.

Targeting IL-13 is highly efficacious in patients with Th2-biased atopic dermatitis (AD), but inhibition of other inflammatory molecules might also limit disease. We investigated the importance of the TNF family cytokine TNF-like weak inducer of apoptosis (TWEAK; TNFSF12) to keratinocyte dysregulation and the pathogenesis of AD in mice and also tested if blocking TWEAK has a similar therapeutic effect as targeting IL-13. Conditional knockout mice lacking Fn14 (TNFRSF12A), the receptor for TWEAK, only in keratinocytes, were repetitively sensitized with house dust mite allergen and analyzed for AD-like skin inflammation. To determine the translational potential, wild-type mice with AD were therapeutically treated with anti-TWEAK and/or anti-IL-13 antibodies, and skin inflammation was assessed. Mice deficient in Fn14 in keratinocytes were resistant to developing maximal clinical features of AD, exhibiting reduced epidermal hyperplasia and dermal thickening, less skin infiltration of immune cells, and downregulated inflammatory gene expression. Moreover, therapeutic neutralization of TWEAK in wild-type mice with AD reduced all of the pathological features to a comparable extent as blocking IL-13. The activity of TWEAK in keratinocytes contributes to AD development, and neutralizing TWEAK represents a future potential therapeutic option in human AD similar to targeting IL-13.

Murine model identifies tropomyosin as IgE cross-reactive protein between house dust mite and coho salmon that possibly contributes to the development of salmon allergy.

Recently, we have developed a method to identify IgE cross-reactive allergens. However, the mechanism by which IgE cross-reactive allergens cause food allergy is not yet fully understood how. In this study, we aimed to understand the underlying pathogenesis by identifying food allergens that cross-react with house dust mite allergens in a murine model. Allergenic protein microarray analysis was conducted using serum from mice intraperitoneally injected with Dermatophagoides pteronyssinus (Der p) extract plus alum or alum alone as controls. Der p, Dermatophagoides farinae (Der f), coho salmon extract-sensitized and control mice were analyzed. Serum levels of IgE against Der p, Der f, coho salmon extract, protein fractions of coho salmon extract separated by ammonium sulfate precipitation and anion exchange chromatography, and recombinant coho salmon tropomyosin or actin were measured by an enzyme-linked immunosorbent assay. A murine model of cutaneous anaphylaxis or oral allergy syndrome (OAS) was established in Der p extract-sensitized mice stimulated with coho salmon extract, tropomyosin, or actin. Protein microarray analysis showed that coho salmon-derived proteins were highly bound to serum IgE in Der p extract-sensitized mice. Serum IgE from Der p or Der f extract-sensitized mice was bound to coho salmon extract, whereas serum IgE from coho salmon extract-sensitized mice was bound to Der p or Der f extract. Analysis of the murine model showed that cutaneous anaphylaxis and oral allergic reaction were evident in Der p extract-sensitized mice stimulated by coho salmon extract. Serum IgE from Der p or Der f extract-sensitized mice was bound strongly to protein fractions separated by anion exchange chromatography of coho salmon proteins precipitated with 50% ammonium sulfate, which massively contained the approximately 38 kDa protein. We found that serum IgE from Der p extract-sensitized mice was bound to recombinant coho salmon tropomyosin. Der p extract-sensitized mice exhibited cutaneous anaphylaxis in response to coho salmon tropomyosin. Our results showed IgE cross-reactivity of tropomyosin between Dermatophagoides and coho salmon which illustrates salmon allergy following sensitization with the house dust mite Dermatophagoides. Our method for identifying IgE cross-reactive allergens will help understand the underlying mechanisms of food allergies.

Dysbiosis and allergy as a background of chronic rhinosinusitis in preschool children

Allergic diseases and chronic inflammatory diseases of the respiratory system, such as asthma or chronic rhinosinusitis, continue to pose a real challenge to modern medicine. The causes of the growing problem generated by these diseases is thought to be in the interaction of genes and the environment. In the light of current knowledge, it seems that the environmentally dependent interaction between the airway microbiota ecosystem and the epithelium is able to shape the functions of the local immune system, producing a number of molecular and clinical consequences. In this paper, an attempt was made to describe the role of microbiota composition disorders (dysbiosis) of the upper respiratory tract and allergies in the development of chronić rhinosinusitis in children. The research results obtained in a Polish cohort of young children diagnosed with chronic rhinosinusitis with or without concomitant asthma are summarised. Some of the children presented with features of secondary dysbiosis, which was associated with sensitisation to house dust mite allergens. It was noted that frequent courses of antibiotic therapy correlated with microbiota dysfunction, reducing biodiversity. It was also observed that patients suffering from asthma had specific dysbiosis in the upper respiratory tract. It is characterised by an altered proportion between the main types of bacteria and is expressed by a reduced Patescibacteria/Actinobacteria ratio, constituting an independent factor of asthma in the study group, similar to atopy and reduced perception of the sweet taste. An attempt was also made to identify possible therapeutic and prophylactic interventions to treat and prevent dysbiosis in children suffering from chronic rhinosinusitis.

Targeting Lewis X oligosaccharide-modified liposomes encapsulated with house dust mite allergen Der f 2 to dendritic cells inhibits Th2 immune response

Allergen-specific immunotherapy (AIT) is the only curative treatment for allergic diseases. However, the long desensitization phase and potentially dangerous allergic side effects limit its broad application. Therefore, safer and more effective vaccines are required. Targeting dendritic cells (DCs) with novel allergen conjugates is a promising strategy for AIT. In this study, a novel vaccine with a DC-targeting effect for AIT was constructed. Liposomes were used as vehicles, and a targeted nanovaccine (Lex-lip-Der f 2) was constructed by loading the recombinant group 2 allergen of Dermatophagoides farinae (Der f 2) and conjugating with the DC-SIGN ligand Lewis X. The effect of the vaccine on DCs and T cell responses and the safety of the vaccine were investigated in vitro. The results showed that the Lex-lip-Der f 2 vaccine was spherical, with size of approximately 128 nm. The protein-loading capacity of the vaccine was 0.106 ± 0.001 mg per mg liposome and protein was gradually released from the liposomes during the first 12 h. Lex-lip-Der f 2 was taken up more efficiently by DCs than non-targeted liposomes or free Der f 2. Besides, Lex-lip-Der f 2 significantly inhibited the release of IL-4, IL-6, and TNF-a from DCs. Accordingly, Der f 2-lip loaded DCs significantly decreased IL-4 levels in autologous naïve CD4+T cells. Moreover, Lex-lip-Der f 2-treated basophils showed lower activation levels. These results suggest that DC-SIGN targeting mediated by Lewis X could inhibit the Th2 cell response and improve vaccine safety, and may be a novel vaccination strategy.

Non-IgE-reactive allergen peptides deteriorate the skin barrier in house dust mite-sensitized atopic dermatitis patients.

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by type 2 cytokine-driven skin inflammation and epithelial barrier dysfunction. The latter is believed to allow the increased penetration of chemicals, toxins, and allergens into the skin. House dust mite allergens, particularly Der p 2, are important triggers in sensitized individuals with AD; the precise actions of these allergens in epithelial biology remain, however, incompletely understood. In this study, we compared the effects of the protein allergen Der p 2 and a mix of non-IgE-reactive Der p 2 peptides on skin cells using patch tests in AD patients and healthy participants. We then analyzed mRNA expression profiles of keratinocytes by single-cell RNA-sequencing. We report that existing barrier deficiencies in the non-lesional skin of AD patients allow deep penetration of Der p 2 and its peptides, leading to local microinflammation. Der p 2 protein specifically upregulated genes involved in the innate immune system, stress, and danger signals in suprabasal KC. Der p 2 peptides further downregulated skin barrier genes, in particular the expression of genes involved in cell-matrix and cell-cell adhesion. Peptides also induced genes involved in hyperproliferation and caused disturbances in keratinocyte differentiation. Furthermore, inflammasome-relevant genes and IL18 were overexpressed, while KRT1 was downregulated. Our data suggest that Der p 2 peptides contribute to AD initiation and exacerbation by augmenting hallmark features of AD, such as skin inflammation, barrier disruption, and hyperplasia of keratinocytes.

Sodium Chloride versus Lactose as a Carrier for House Dust Mite Allergen in Allergen Chamber Studies: A Clinical Study to Assess Noninferiority

Introduction: In the Fraunhofer allergen challenge chamber (ACC), a standardized, universal, good manufacturing practice-conforming technology using a spray dried solution of lactose (L) and allergen extract has been established. In this study, we investigated the noninferiority of hypertonic sodium chloride (S) versus L as a carrier for house dust mite (HDM) allergen to simplify manufacturing, reduce costs, and allow for wider use. Methods: Using a participant-blinded, sham exposure-controlled, single-arm, sequential intervention study, we challenged adults with HDM allergic rhinitis five times in the ACC. Participants were first exposed to S, L, and clean air (block 1), followed by S + HDM and L + HDM (block 2). Primary endpoints were mean total nasal symptom score (TNSS) and mean nasal secretion weight. Results: 19 participants were enrolled in the study (10 females; mean age 32 years [22–49], 4 with mild allergic asthma). The safety profile of S + HDM and L + HDM was similar; eight participants experienced mild procedure-related adverse events including tiredness, cough, and dyspnea. Due to dropouts, 13 participants completed the study and were evaluated. Mean TNSS and nasal secretion were as follows: S 0.98, 0.28 g; L 1.1, 0.20 g; clean air 1.1, 0.23 g; S + HDM 5.7, 4.8 g; L + HDM 5.1, 5.1 g. Separate block 1/block 2 MANOVAs with TNSS and nasal secretion as dependent variables revealed no significant differences between the carriers, neither alone and compared with clean air (p = 0.2059, Wilk’s λ = 0.78) nor combined with HDM (p = 0.3474, Wilk’s λ = 0.89). Noninferiority of S was established using a meta-analysis-based minimal clinical important difference of −0.55: mean TNSS difference between S + HDM and L + HDM was 0.62 (90% CI: −0.51 to 1.74). Conclusion: S as an HDM carrier was safe and well tolerated. It was noninferior to L which makes it an adequate and easy-to-use carrier substitute.

Toll-like receptor 4 and Syk kinase shape dendritic cell-induced immune activation to major house dust mite allergens.

House dust mite (HDM) is a major cause of respiratory allergic diseases. Dendritic cells (DCs) play a central role in orchestrating adaptive allergic immune responses. However, it remains unclear how DCs become activated by HDM. Biochemical functions of the major HDM allergens Der p 1 (cysteine protease) and Der p 2 (MD2-mimick) have been implicated to contribute to DC activation. We investigated the immune activating potential of HDM extract and its major allergens Der p 1 and Der p 2 using monocyte-derived DCs (moDCs). Maturation and activation markers were monitored by flow cytometry and cytokine production by ELISA. Allergen depletion and proteinase K digestion were used to investigate the involvement of proteins, and in particular of the major allergens. Inhibitors of spleen tyrosine kinase (Syk), Toll-like receptor 4 (TLR4) and of C-type lectin receptors (CLRs) were used to identify the involved receptors. The contribution of endotoxins in moDC activation was assessed by their removal from HDM extract. HDM extract induced DC maturation and cytokine responses in contrast to the natural purified major allergens Der p 1 and Der p 2. Proteinase K digestion and removal of Der p 1 or Der p 2 did not alter the immune stimulatory capacity of HDM extract. Antibodies against the CLRs Dectin-1, Dectin-2, and DC-SIGN did not affect cytokine responses. In contrast, Syk inhibition partially reduced IL-6, IL-12 and completely blocked IL-10. Blocking TLR4 signaling reduced the HDM-induced IL-10 and IL-12p70 induction, but not IL-6, while endotoxin removal potently abolished the induced cytokine response. Our data strongly suggest that HDM-induced DC activation is neither dependent on Der p 1 nor Der p 2, but depend on Syk and TLR4 activation, which might suggest a crosstalk between Syk and TLR4 pathways. Our data highlight that endotoxins play a potent role in immune responses targeting HDM.

Complement C1q essential for aeroallergen sensitization via CSF1R+ conventional dendritic cells type 2

Dendritic cells (DCs) are heterogeneous, comprising multiple subsets with unique functional specifications. Our previous work has demonstrated that the specific conventional type 2 DC subset, CSF1R+cDC2s, plays a critical role in sensing aeroallergens. It remains to be understood how CSF1R+cDC2s recognize inhaled allergens. We sought to elucidate the transcriptomic programs and receptor-ligand interactions essential for function of this subset in allergen sensitization. We applied single-cell RNA sequencing to mouse lung DCs. Conventional DC-selective knockout mouse models were employed, and mice were subjected to inhaled allergen sensitization with multiple readouts of asthma pathology. Under the clinical arm of this work, human lung transcriptomic data were integrated with mouse data, and bronchoalveolar lavage (BAL) specimens were collected from subjects undergoing allergen provocation, with samples assayed for C1q. We found that C1q is selectively enriched in lung CSF1R+cDC2s, but not in other lung cDC2 or cDC1 subsets. Depletion of C1q in conventional DCs significantly attenuates allergen sensing and features of asthma. Additionally, we found that C1q binds directly to human dust mite allergen, and the C1q receptor CD91 (LRP1) is required for lung CSF1R+cDC2s to recognize the C1q-allergen complex and induce allergic lung inflammation. Lastly, C1q is enriched in human BAL samples following subsegmental allergen challenge, and human RNA sequencing data demonstrate close homology between lung IGSF21+DCs and mouse CSF1R+cDC2s. C1q is secreted from the CSF1R+cDC2 subset among conventional DCs. Our data indicate that the C1q-LRP1 axis represents a candidate for translational therapeutics in the prevention and suppression of allergic lung inflammation.

The impact of allergen-specific immunotherapy with house dust mite allergens on the quality of life in children with bronchial asthma

Controlled studies of the impact of allergen-specific immunotherapy on the quality of life of patients provide mixed results. Purpose. To evaluate the quality-of-life dynamics in children with bronchial asthma during 3 years of treatment with allergen immunotherapy with house dust mite allergens and one year after its completion.Material and methods. In an open-label, five-year prospective study, the clinical efficacy of allergen immunotherapy and quality of life were assessed using a validated PAQLQ(S) questionnaire at the end of the baseline year (before starting allergen immunotherapy), at the end of each of allergen immunotherapy year, and at the end of the follow-up year. The study was completed by 25 patients of the main group (16 boys, 9 girls aged 8.3 [6.7; 11.5] years at inclusion) with moderate bronchial asthma in 17 children (68%), mild bronchial asthma in 8 children (32%), and 25 children of the comparison group (who received a similar amount of pharmacological therapy but not allergen immunotherapy), matched as pairs-copies to the children of the main group.Results. During the first two years of allergen immunotherapy, changes in the level of quality of life were multidirectional. By the end of the third year of allergen immunotherapy, there was a trend towards an improvement in overall quality of life and a decrease in the effect of bronchial asthma symptoms upon quality of life. A year after allergen immunotherapy completion in the main group, a significant increase in overall quality of life was noted, in comparison with the level of quality of life before the start of treatment (p=0.03) and in comparison with the level in the comparison group (p=0.046).Conclusion. The data obtained objectively indicate an increase in quality of life in children with asthma as a result of a full course of allergen immunotherapy. The achieved positive results were maintained for at least 1 year after the end of treatment.

Effects of indoor air quality and home environmental characteristics on allergic diseases among preschool children in the Greater Taipei Area

Indoor air quality and home environmental characteristics are potential factors associated with the onset and exacerbation of allergic diseases. Our study examined the effects of these factors on allergic diseases (i.e., asthma, allergic rhinitis, allergic conjunctivitis, and atopic dermatitis) among preschool children. We recruited a total of 120 preschool children from an ongoing birth cohort study in the Greater Taipei Area. A comprehensive environmental evaluation was conducted at each participant's residence and included measurements of indoor and outdoor air pollutants, fungal spores, endotoxins, and house dust mite allergens. A structured questionnaire was used to collect information on the allergic diseases and home environments of participants. Land-use characteristics and points of interest in the surrounding area of each home were analyzed. Other covariates were obtained from the cohort data. Multiple logistic regressions were used to examine the relationships between allergic diseases and covariates. We observed that all mean indoor air pollutant levels were below Taiwan's indoor air quality standards. After adjustment for covariates, the total number of fungal spores and the ozone, Der f 1, and endotoxin levels were significantly associated with increased risks of allergic diseases. Biological contaminants more significantly affected allergic diseases than other pollutants. Moreover, home environmental characteristics (e.g., living near power facilities and gas stations) were associated with an increased risk of allergic diseases. Regular and proper home sanitation is recommended to prevent the accumulation of indoor pollutants, especially biological contaminants. Living away from potential sources of pollution is also crucial for protecting the health of children.

Barrier-forming, drug-free nasal spray reduces allergic symptoms induced by house dust mite allergen.

House Dust Mite (HDM) is the most common indoor allergen triggering allergic symptoms. First-line pharmacotherapy treatment is recommended in international guidelines, while the avoidance of allergens represents a still unmet guideline principle. AM-301 is a new non-pharmacological nasal spray that creates a protective gel-like barrier on the nasal mucosa, preventing the contact with the allergens. This randomized, open-label, 3-period crossover study assessed the efficacy and safety of AM-301. The objective was to determine whether AM-301 reduces allergic rhinitis (AR) symptoms in patients exposed to HDM allergens. Adults with confirmed Perennial Allergic Rhinitis (PAR; n=37) were exposed to HDM allergen in a controlled Allergen Exposure Chamber before and during a treatment course of AM-301 (in six different sequences) within 3weeks (A: One spray AM-301 per nostril/B: Two sprays AM-301 per nostril/C: no treatment). For the primary efficacy analysis, data from the total nasal symptom score (TNSS) were pooled from treatment A+B (D) and analyzed with Analysis of Covariance Model. As secondary endpoints, single time points, visits and symptoms were analyzed. The primary endpoint (overall change in TNSS from baseline over all three visits) showed significant results (p=0.0085). A comparable alleviation of all four symptoms (itchy nose, nasal congestion, runny nose, sneezing) by the protective layer started to emerge after 40min and lasted up to 180min (end of challenge). AM-301 resulted to be safe and well-tolerated. AM-301 significantly reduced HDM-related allergic symptoms in a standardized allergen challenge. Protection was observed to last up to 180min.

Collaborative cross strain CC011/UncJ as a novel mouse model of T2-high, severe asthma

Among asthmatics, there is significant heterogeneity in the clinical presentation and underlying pathophysiological mechanisms, leading to the recognition of multiple disease endotypes (e.g., T2-high vs. T2-low). This heterogeneity extends to severe asthmatics, who may struggle to control symptoms even with high-dose corticosteroid treatment and other therapies. However, there are limited mouse models available to model the spectrum of severe asthma endotypes. We sought to identify a new mouse model of severe asthma by first examining responses to chronic allergen exposure among strains from the Collaborative Cross (CC) mouse genetics reference population, which contains greater genetic diversity than other inbred strain panels previously used for models of asthma. Mice from five CC strains and the often-used classical inbred strain BALB/cJ were chronically exposed to house dust mite (HDM) allergen for five weeks followed by measurements of airway inflammation. CC strain CC011/UncJ (CC011) exhibited extreme responses to HDM including high levels of airway eosinophilia, elevated lung resistance, and extensive airway wall remodeling, and even fatalities among ~ 50% of mice prior to study completion. Compared to BALB/cJ mice, CC011 mice had stronger Th2-mediated airway responses demonstrated by significantly elevated total and HDM-specific IgE and increased Th2 cytokines during tests of antigen recall, but not enhanced ILC2 activation. Airway eosinophilia in CC011 mice was completely dependent upon CD4+ T-cells. Notably, we also found that airway eosinophilia in CC011 mice was resistant to dexamethasone steroid treatment. Thus, the CC011 strain provides a new mouse model of T2-high, severe asthma driven by natural genetic variation likely acting through CD4+ T-cells. Future studies aimed at determining the genetic basis of this phenotype will provide new insights into mechanisms underlying severe asthma.

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

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. 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. 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. 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.

Evaluation of subjective scale in allergen nasal provocation test

Objective:To compare the clinical value of visual analogue scale （VAS）, Lebel scale and total nasal symptom scores （TNSS） in evaluating nasal allergen provocation test （NAPT）. Methods:A total of 151 patients suspected of allergic rhinitis admitted to the Department of Otolaryngology-Head and Neck Surgery of our hospital from April 2020 to September 2020 were included, of which 76 were positive for house dust mites and 75 were negative for allergens. Nasal airway resistance（NAR） was measured by active anterior nasal manometry. Nasal symptoms were evaluated by VAS, Lebel and TNSS. House dust mite allergen was used for NAPT by spray method. An increase≥40% in NAR was used as the gold standard for objective evaluation of NAPT. ROC curves of VAS, Lebel and TNSS were drawn to compare the evaluation effectiveness of different subjective evaluation methods, and the optimal critical point of each ROC curve was obtained. Results:With NAR increased by ≥40% as the gold standard, the area under ROC curve of VAS was 0.884, and the sensitivity and specificity were 97.75% and 80.65%, respectively. The area under ROC curve of Lebel was 0.773, and the sensitivity and specificity were 68.54% and 75.81%, respectively. The area under ROC curve of TNSS was 0.792, and the sensitivity and specificity were 68.54% and 79.03%, respectively. There was no significant difference between Lebel and TNSS（P>0.05）. The VAS differed significantly from Lebel and TNSS（P<0.05）. The Kappa values of VAS, Lebel, TNSS and NAR were 0.803, 0.432 and 0.459, respectively. Conclusion:The VAS, Lebel, TNSS subjective scale and NAR are consistent in evaluating the efficacy of NAPT, with the VAS assessment showing highest consistency with NAR. As objective assessment instruments are not widely used in China, subjective assessment method could be adopted to evaluate the efficacy of NAPT in clinical practice, and VAS scale is recommended as a priority.

Site-specific tyrosine nitration of group 1 allergens of house dust mite Dermatophagoides farinae (Der f 1) and Dermatophagoides pteronyssinus (Der p 1) in indoor dusts

Nitration can enhance the allergenicity of proteins. The nitration status of house dust mite (HDM) allergens in indoor dusts, however, remains to be elucidated. In the study, site-specific tyrosine nitration degrees of the two important HDM allergens Der f 1 and Der p 1 in indoor dust samples were investigated by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The measured concentrations of native and nitrated allergens in the dusts were in the range of 0.86–29 μg g−1 for Der f 1 and from below the detection limit to 29 μg g−1 for Der p 1. Site-specific analysis revealed that all ten tyrosine residues in Der f 1 and Der p 1 were nitrated to different degrees in the investigated samples. The preferred nitration sites were Y56 in Der f 1 and Y37 in Der p 1 with the nitration degrees of 7.6–84% and 17–96% among the detected tyrosine residues, respectively. The measurements reveal high site-specific nitration degrees for tyrosine in Der f 1 and Der p 1 detected in the indoor dust samples. Further investigations are required to find out if the nitration really aggravates the health effects of HDM allergens and if the effects are tyrosine site-dependent.

Persistence in allergen immunotherapy: A longitudinal, prescription data-based real-world analysis.

Allergic rhinitis (AR) is a widespread disease with increasing prevalence in developed countries. The only treatment that tackles the underlying causes is allergen immunotherapy (AIT). This treatment is performed through two application routes, the subcutaneous immunotherapy (SCIT) or the sublingual immunotherapy (SLIT). However, persistence during the long course of treatment over 3years is key for the efficacy of this treatment option. The impaired adherence significantly impacts public health resources. The aim of this study was to assess the persistence of AIT for both application routes. IQVIATM LRx was used to identify patients starting AIT between 2009 and 2018 with grass pollen (GP), early flowering tree pollen (EFTP) and house dust mite (HDM) allergens. Patients were classified within each allergen category by AIT groups (subcutaneous depigmented polymerised allergen AIT [dSCIT], other subcutaneous AIT [oSCIT] and SLIT) and age (5-11 years, 12-17 years, 18+ years). Furthermore, they were followed up for up to 3years until the cessation of treatment. Patients, who were still on treatment after 3years were deemed to be censored. Kaplan-Meier curves of persistence were generated and compared by log-rank tests. The number of patients included in the three allergen categories was 38,717GP, 23,183 EFTP, and 41,728 HDM AIT. In all allergen categories and for any product group, patient persistence decreased with increasing age class with the difference between 5-11 years and 12-17 years greater than between the latter and 18+ years. The percentage of patients completing the first year of AIT was low, particularly for SLIT where 22.2%-27.1% of patients remained persistent after 12months. The equivalent figures for dSCIT were 52.0%-64.1% and for oSCIT 38.3%-50.3%. Persistence in AIT in AR was low in this retrospective prescription-based database and was clearly linked to patient age and application route.

Lung pathogenic, P2RX7-dependent CD4 +T cell immune responses to influenza are exacerbated by co-exposure with lung allergens

Abstract Extracellular ATP (eATP) is a danger signal released by inflamed tissues, and can be sensed by immune cells via P2RX7. P2RX7 promotes lung pathology induced by influenza infection, by inducing exacerbated numbers of lung CD4 +T cells. In response to influenza, lung CD4 +T cells are comprised of a type 1 (Th1)-like population, and a subset resembling follicular helper (Tfh) CD4 +T cells; this subset is called tissue-resident helper (Trh). Trh cells amplify lung effector immune responses. Trh cells express high P2RX7 levels, and current research in our laboratory shows that P2RX7 is crucial for Trh cell establishment and subsequent lung damage. We have also found that the intensity of lung damage caused by influenza is positively correlated with P2RX7 +lung Trh cells. It is not clear, however, how concomitant exposure to influenza and type 2 immunity-inducing lung allergens (a common clinical occurrence in the United States) affect P2RX7 +lung Trh cells and their resultant tissue damage. We investigated this, using House Dust Mite (HDM) allergen exposure together with Influenza (PR8) infection. HDM/PR8 co-exposure induced worsening of lung inflammation, compared to single exposure to PR8. This inflammation had type 1 characteristics (i.e. parenchymal immune cell accumulation and absence of mucus). The increased lung damage generated by HDM/PR8 exacerbated the generation of influenza-specific P2RX7 +lung Trh cells. The accumulation of lung Trh cells (and subsequent tissue damage) caused by HDM/PR8 was abolished in T cell-specific P2RX7-knockout mice. Our results suggest that local inflammation, eATP release and sensing, and lung Trh cells together dictate the intensity of lung damage, regardless of the nature of the lung disease agent. R01AI170649