House Dust Mite Allergic Patients Research Articles

The nasal basal cell population shifts toward a diseased phenotype with impaired barrier formation capacity in allergic rhinitis

BackgroundThe integrity of the airway epithelium is guarded by the airway basal cells that serve as progenitor cells and restore wounds in case of injury. Basal cells are a heterogenous population and specific changes in their behavior are associated with chronic barrier disruption; mechanisms that have not been studied in detail in allergic rhinitis (AR). ObjectiveWe here aim to study basal cell (sub)types in AR and healthy controls. MethodsscRNAseq of the nasal epithelium was performed on non-allergic and house dust mite allergic AR patients to reveal basal cell diversity and to identify allergy-related alterations. Flow cytometry, immunofluorescence staining and in vitro experiments using primary basal cells were performed to confirm phenotypic findings at protein level and functionally. ResultsscRNAseq, flow cytometry and immunofluorescence staining revealed that basal cells are abundantly and heterogeneously present in the nasal epithelium, suggesting specialized subtypes. The total basal cell fraction within the epithelium in AR is increased compared to controls. scRNAseq demonstrated that potentially beneficial basal cells are missing in AR epithelium, while an activated population of allergy-associated basal cells is more dominantly present. Furthermore, our in vitro proliferation, wound healing assay and ALI cultures show that AR-associated basal cells have altered progenitor capacity compared with non-allergic basal cells. ConclusionsThe nasal basal cell population is abundant, diverse and shifts towards a diseased state in AR. The absence of potentially protective subtypes and the rise of a pro-inflammatory population suggest that basal cells are important players in maintaining epithelial barrier defects in AR.

Investigating Forkhead Box O Transcription Factor 1 Gene's Relation to Immunoglobulin E in House Dust Mite-Allergic Asthma Patients.

House dust mite (HDM)-allergic asthma is an abnormal immune response to extrinsic aeroallergens found in human vicinities. Studying the role of the associated immunity biomarkers and their interplay helps in discovering novel therapeutic strategies that can be used in adjunct with effective long-term immunotherapy. This study investigates the total serum IgE, FoxO1, and Sirtuin 1 (SIRT1) gene expressions in HDM-allergic asthma patients. We enrolled 40 patients for each of the following three groups: an HV group of healthy volunteers and HDM/AA and HDM/SCIT groups of HDM-allergic asthma patients who did not and who did receive immunotherapy before recruitment in this study, respectively. The results elucidated that total IgE was strikingly elevated in the HDM/AA group and showed little decline in the HDM/SCIT group. Both FoxO1 and SIRT1 gene expressions showed the highest levels in the HDM/SCIT group. There was a negative correlation between total IgE and both FoxO1 and SIRT1 in the HDM/AA group while there was a positive correlation with SIRT1 in the HDM/SCIT group. In conclusion, the interplay of the three immunity biomarkers related to HDM-allergic asthma after the course of immunotherapy treatment suggests further, broader studies on the feasibility of their role as immunity biomarkers in the control and remission of HDM-allergic asthma.

Investigating the T regulatory cells and Sirtuin-I serum level in immunotherapy treated house dust mite allergic asthma patients

Objectives House dust mite aeroallergens are predominant triggers of frequent asthma attacks among adults and children. The intensity of asthma and immune reaction necessitates treatment alternatives based on adjusting chosen immunity biomarkers to control the exacerbation of symptoms and establish long-term immune tolerance. In this study, we selected CD4+CD25+Foxp3+ regulatory T cells (Tregs), FOXP3, and Sirtuin-1 as they are known to have a potential role in the immune reaction in different allergic diseases. We investigated their interplay during HDM allergic asthma and its respective immunotherapy. Methods Eighty-four subjects were divided into 3 groups; healthy controls (CT), HDM asthma patients without immunotherapy (WOIT), and HDM asthma patients treated with subcutaneous immunotherapy for 6 months before recruitment (WIT). They were enrolled according to the pulmonary function, skin prick tests, and HDM-specific IgE. CD4+ CD25+ and CD4+ CD25+ FOXP3+hi T cells Cell percentages, FOXP3 gene expression, and Sirtuin-1 (Sirt1) serum level were analyzed. Results We found that there is a significant difference between WOIT and WIT groups in the CD4+ CD25+ and CD4+ CD25+ FOXP3+hi T cell percentages. While there is no statistically significant difference between WOIT and WIT groups in FOXP3 level. On the controversy, the SIRT1 level in the CT group (4.53 ± 3.880) significantly decreased in the WOIT and WIT groups. Conclusion This study revealed that both CD4 CD25 and CD4 CD25 high FOXP3 cell percentages increased in the WIT group and declined in the WOIT group. While, FOXP3 gene expression increased in both groups. In addition, the Sirt1 serum level showed some improvement in WIT group after a serious drop in the WOIT group comparing with the CT group. The modulation of these biomarkers for the remission and control of allergic asthma can be a prognostic outcome of immunotherapy which needs to be confirmed by larger scale studies.

House dust mite allergy: The importance of house dust mite allergens for diagnosis and immunotherapy

House dust mite (HDM) allergy belongs to the most important allergies and affects approximately 65–130 million people worldwide. Additionally, untreated HDM allergy may lead to the development of severe disease manifestations such as atopic dermatitis or asthma. Diagnosis and immunotherapy of HDM allergic patients are well established but are often hampered by the use of mite extracts that are of bad quality and lack important allergens. The use of individual allergens seems to be a promising alternative to natural allergen extracts, since they represent well-defined components that can easily be produced and quantified. However, a thorough characterization of the individual allergens is required to determine their clinical relevance and to identify those allergens that are required for correct diagnosis of HDM allergy and for successful immunotherapy. This review gives an update on the individual HDM allergens and their benefits for diagnosis and immunotherapy of HDM allergic patients.

Retrospective evaluation of adverse reactions after subcutaneous allergen-specific immunotherapy in children with house dust mite allergy.

Although it is accepted as an effective and safe treatment way, side effects can be observed as a result of subcutaneous immunotherapy (SCIT). In our study, it was aimed to evaluate the local and systemic reactions in children after SCIT and the factors that may be associated with these reactions. Our study included 138 house dust mite allergic patients with asthma and/or allergic rhinitis who underwent SCIT in the Pediatric Allergy and Immunology Outpatient Clinic between November 2013 and April 2022. Sociodemographic, clinical, laboratory features, and development of adverse reactions after SCIT were analyzed from patient files. The median age of 138 patients was 9.0 years. About 56.5% (n=78) were male, 43.5% (n=60) were female. Of the patients, 55.1% (n=76) had asthma and allergic rhinitis. A total of 7366 SCIT injections were administered to all patients in our clinic. The total number of observed adverse reaction was 118. 50.7% of the patients (n=70) experienced at least one adverse reaction after SCIT. The rate of development of adverse reactions per injection was 1.6% (local: 1.0%, large local: 0.1%, systemic: 0.5%). Although serious systemic reactions and death were not observed in our patients; care should be taken in terms of the development of adverse reactions during SCIT in children.

Correlation of the combined symptom and medication score with quality of life, symptom severity and symptom control in allergic rhinoconjunctivitis.

BackgroundThe European Academy of Allergy and Clinical Immunology recommended the Combined Symptom and Medication Score (CSMS) as primary endpoint in clinical trials on allergen‐specific immunotherapy (AIT) in allergic rhinoconjunctivitis. Here, the correlation between the CSMS and the validated standardised Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ(S)), Rhinitis Control Assessment Test (RCAT) and Visual Analogue Scale (VAS) was analysed.MethodsTwo prospective, multicentre, non‐interventional studies on tree pollen, grass pollen and house dust mite allergic patients were performed. The first study comprised 167 patients receiving AIT (AIT population), and the second included 56 patients treated with symptomatic medication only (control population). For up to two seasons (pollen)/exposure periods (house dust mites), participants documented their symptoms and medication intake in a CSMS diary, including VAS. In addition, the standardised RQLQ(S) and the RCAT were completed during study visits.ResultsComparison between CSMS and RQLQ(S) revealed a positive correlation in the AIT population (r = 0.426) and in the control population (r = 0.569). For CSMS and RCAT, a negative correlation with r = −0.409 (AIT) and r = −0.547 (control) was shown. Positive correlation between CSMS and VAS was also demonstrated with r = 0.585 (AIT) and r = 0.563 (control).ConclusionThese results support the assumption that the CSMS correlates with quality of life, symptom severity and symptom control on the one hand, while the moderate strength of correlations on the other hand mirrors distinctions of the CSMS compared to the assessments used here.

Bioinformatics analysis of nasal epithelial cell gene expression in seasonal and perennial allergic rhinitis

Objective: Transcriptome sequencing and bioinformatics analysis were performed on the gene expression of nasal epithelial cells in patients with seasonal allergic rhinitis (AR) and perennial AR, so as to obtain the differences in the gene expression of nasal epithelial cells between seasonal AR and perennial AR. Methods: The human nasal epithelial cell line(HNEpC) was cultured in vitro, treated with 100 μg/ml mugwort or house dust mite (HDM) extracts for 24 hours. Total cell RNA was extracted, and quantitative real-time polymerase chain reaction (qPCR) was used to detect the expression of cytokines, including IL-6, IL-8, IL-33 and thymic stromal lymphopoietin (TSLP). From November 2019 to November 2020, 3 seasonal AR patients, 3 perennial AR patients, and 3 healthy controls who attended the Department of Otolaryngology Head and Neck Surgery, China-Japan Union Hospital of Jilin University were analyzed. The patients' primary nasal epithelial cells were cultured in vitro, treated with corresponding allergens for 24 hours. Total RNA was extracted for transcriptome sequencing, and the sequencing results were analyzed by bioinformatics. Results: The qPCR results showed that the cytokines IL-6, IL-8, IL-33 and TSLP of HNEpC treated with mugworts extracts and HDM extracts had the same trend of change. After the nasal epithelial cells from patients with seasonal AR and perennial AR were treated with corresponding allergens, there were differences in biological processes and signal pathways between those and control. Gene ontology (GO) enrichment analysis showed that the differentially expressed genes (DEG) in AR patients allergic to mugwort were mainly enriched in the oxidation-reduction process, the negative regulation of apoptosis process, and the cell adhesion; the DEG in AR patients allergic to HDM were mainly enriched in cell adhesion, the negative regulation of cell proliferation and the response to drug. Enrichment analysis of Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathway showed that the DEG of AR patients allergic to mugwort were significantly enriched in arachidonic acid metabolism, p53 signaling pathway and transforming growth factor β (TGF-β) signaling pathway, while the DEG of AR patients allergic to HDM were mainly enriched in cells cycle, Fanconi anemia pathway and DNA replication. Gene Set Enrichment Analysis (GSEA) showed that the inflammatory response, TNF-α/NF-κB signaling pathway and IL-2/STAT5 signaling pathway were significantly up-regulated in AR patients allergic to mugwort, indicating the promotion of inflammatory response; and AR patients allergic to HDM had significant down-regulation of G2M, E2F, and MYC, indicating the inhibition of cell proliferation. The protein-protein interaction network showed that TNF and CDK1 were the most interacting proteins in mugwort and HDM allergic AR patients, respectively. Conclusion: Seasonal AR and perennial AR may affect the different biological processes and signal pathways of nasal epithelial cells, leading to differences in the occurrence and development of AR.

Shrimp sensitization in house dust mite algerian allergic patients: A single center experience

BackgroundCross-reactivity between shrimp and house dust mite (HDM) proteins has been widely documented. However, a significant geographical variability in sensitization patterns and cross-reactive allergens has been reported which may impact the diagnosis and management of shrimp allergy among HDM-shrimp co-sensitized patients. This study aimed to investigate the prevalence of shrimp and tropomyosin sensitization among HDM-allergic patients in order to understand the local epidemiology to inform the development of targeted diagnostic and therapeutic tools. MethodsFour hundred forty-six (446) HDM-allergic patients and 126 atopic controls were screened for shrimp-specific IgE using the IMMULITE 2000 XPI® System. HDM-shrimp sensitized subjected were also tested for IgE tropomyosin (nPen m 1) and thoroughly interviewed about their shellfish consumption habits. Tropomyosin sensitized patients were subjected to further analysis including measurement of IgE specific to squid and crab. ResultsThe prevalence of shrimp sensitization in the HDM-allergic population was 20.4% vs 0% in the control group. Of them 63.7% were clinically allergic to shrimp, while 9 cases had no history of allergic reaction to this food and 24 patients reported not having consumed shrimp before. Besides, 72.5% of the HDM-shrimp sensitized subjects had tropomyosin-specific IgE with a positivity rate of 82.8% among shrimp-allergic patients. Among tropomyosin reactors, 95.5% were sensitized to crab and 89.5% to squid, none of them had previously ingested neither crab nor squid. Nevertheless, one-third of HDM-shrimp sensitized patients who never consumed shrimp before did not react to tropomyosin. ConclusionsShrimp allergy seems to be strictly dependent on HDM sensitization, at least in this geographical area. Therefore, HDM allergic patients should be systematically screened for shrimp sensitization and asked about the consumption of shellfish. Tropomyosin is a major and clinically relevant shrimp allergen that accounts for shellfish-HDM cross-reactivity. However, other components could be involved.

Correlation between sensitization to house dust mite major allergens, age, and symptoms in Japanese house dust mite allergic subjects

Der p 23 has recently been recognized as a new house dust mite (HDM) major allergen that may be linked to the development of asthma in HDM allergic patients. This study aimed to investigate the frequency of sensitization to HDM major allergen components including Der p 23 and to examine the correlation between HDM-sensitization and AR symptom score in Japanese HDM allergic rhinitis (AR) patients without allergic asthma.Serum samples (n = 120) collected from Japanese HDM AR patients (12 to 64 years) without asthma were assessed for allergen-specific IgE (s-IgE) by ImmunoCAP (Dermatophagoides pteronyssinus (D. pteronyssinus; Der p) extract, Der p 23) or immunosolid-phase allergen chip (Der p 1, Der p 2).Japanese HDM AR patients without asthma showed a high prevalence of allergic sensitization to the HDM major allergens Der p 1 (94.2%), Der p 2 (97.5%) and Der p 23 (71.7%). No difference in the prevalence was detected for Der p 1 and Der p 2 s-IgE among three age groups. However, the prevalence of Der p 23 s-IgE was significantly higher in the younger group compared to the elderly group. No significant correlation was found between AR symptom scores and concentration of s-IgE towards Der p extract and any of the three HDM major allergens.Although the prevalence of sensitization towards D. pteronyssinus major allergens is high in Japanese AR patients without asthma, there was no correlation between allergen specific IgE including IgE towards Der p 23 and AR symptom in this population.

Response to González-Pérez et al

We earlier found that house dust mite (HDM) allergens, which occur mainly in mite bodies but not in feces (e.g., Der p 10, Der p 11, and Der p 14), are more frequently recognized by HDM allergic patients with atopic dermatitis (AD) than HDM allergic patients suffering from respiratory allergy (Banerjee et al., 2015). The fact that certain types of the mite body‒derived allergens such as Der p 11 do not become easily airborne and are recognized by >50% of patients with AD suggested that this allergen may be considered a major allergen in AD and that sensitization may eventually occur through the skin (Banerjee et al., 2015).

Long-term benefits of targeted micronutrition with the holoBLG lozenge in house dust mite allergic patients

Summary Purpose The long-term effects of targeted micronutrition with the holoBLG lozenge in house dust mite (HDM) allergic rhinoconjunctivitis (ARC) patients were evaluated at a follow-up visit in an allergen exposure chamber (AEC). Methods Patients who were supplemented for 3‑months with the holoBLG lozenge in a previous study with two controlled HDM-AEC challenges [visits: V1, V3] were recruited for a third AEC challenge (V5) 7–8 months after cessation of supplementation. Symptoms (nose, conjunctival, bronchial, others), well-being, and lung function parameters were recorded exactly as in the previous study. Primary endpoint was change in median Total Nasal Symptom Score (TNSS) at V5 compared to V1. Secondary endpoints included e.g. change in median Total Symptom Score (TSS) and the exploratory analysis of temporal evolution of symptom scores using linear mixed effects models. Results Of the 32 patients included in the original study, 27 could be recruited for the follow-up visit with a third AEC challenge. An improvement of 20% (p = 0.15) in the primary endpoint TNSS [V1: 2.5 (interquartile range [IQR]: 1–4), V5: 2.0 (IQR: 1–3)] was observed; 40% (p = 0.04) improvement was seen for the TSS [V1: 5.0 (IQR: 3–9), V5: 3.0 (IQR: 2–5.5)]. Analysis of temporal evolution of all symptom scores, and the personal well-being revealed sustained, clinically meaningful improvement at V5 compared to V1. No relevant lung function parameter differences were observed. Conclusions Sustained long-term reduction of TNSS (primary endpoint) and sustained long-term improvement of secondary endpoints (temporal evolution of all symptom scores and well-being) were demonstrated 7–8 months after cessation of holoBLG supplementation, indicative of a long-lasting nature of immune resilience induced by holoBLG. Trial registration The study was registered at clinicaltrials.gov (NCT04872868).

Thermal processing of insect allergens and IgE cross-recognition in Italian patients allergic to shrimp, house dust mite and mealworm

Edible insects are considered as a promising and sustainable alternative protein source for humans, although risk assessments, with particular reference to the allergic potential of insect proteins, are required. Considering that insects are likely to be consumed after processing, it is crucial to assess how processing can influence allergenicity. In our study, we investigated how boiling and frying affect the IgE cross-recognition of proteins from five edible insects (mealworm, buffalo worm, silkworm, cricket and grasshopper). We considered three groups of Italian patients allergic to shrimps and to house dust mites, who had never consumed insects before and two subjects with occupational allergy and food sensitization to mealworm. Our data suggest that thermal processing may change the solubility of proteins, thereby resulting in a protein shift from water-soluble fractions to water-insoluble fractions. Immunoblot and LC-MS/MS analyses have shown that tropomyosin may play an important role as a cross-allergen for house dust mite and shrimp allergic patients, while larval cuticle protein seems to play a major role in the cross-reactivity of patients primarily sensitized to mealworm.On the basis of our results, the effects of processing appear to be protein-, species- and treatment-specific. Therefore, house dust mite, shrimp and mealworm allergic patients should consume insects with caution, even after thermal processing.

Targeted micronutrition via holo-BLG based on the farm effect in house dust mite allergic rhinoconjunctivitis patients – first evaluation in a standardized allergen exposure chamber

Abstract Purpose Evaluation of a lozenge for targeted micronutrition (holo-BLG), a new invention based on the farm effect, in house dust mite (HDM) allergic rhinoconjunctivitis (ARC) patients in a standardized allergen exposure chamber (AEC). Methods Eligible HDM allergic patients were exposed to HDM raw material in an AEC for 120 min before (V1) and after (V3) 3 months of holo-BLG supplementation. Nasal, conjunctival, bronchial and other symptoms were rated by the patients every 10 min and, wellbeing, peak nasal inspiratory flow (PNIF), and lung function parameters every 30 min. Primary endpoint was the change in median Total Nasal Symptom Score (TNSS) at V3 compared to V1 at 120 min of exposure. Secondary endpoints consisted of the exploratory analysis of the temporal evolution of symptom scores using linear mixed effects models. Results A total of 32 patients were included in the analysis. A significant improvement of 60% (p = 0.0034) in the primary endpoint TNSS (V1 2.5 [interquartile range, IQR 1–4], V3 1.0 [IQR 1–3]) was observed. 40% improvement was seen for the Total Symptom Score (V1 5.0 [IQR 3–9], V3 3.0 [IQR 2–4]; [Wilcoxon test: confidence interval 1.5–4.0, p < 0.0003]). The analysis of the temporal evolution of all symptom scores and the personal wellbeing revealed clinically meaningful improvement over time, manifested in a lower symptom increase during the final HDM exposure. No relevant differences were observed for PNIF and lung function parameters. Safety and tolerability were rated as excellent. Conclusions The effect of holo-BLG resulting in immune resilience might help to fight the allergy epidemic on a new front based on targeted micronutrition of immune cells. Trial registration The study was retrospectively registered at clinicaltrials.gov (NCT04477382).

Expression in Escherichia coli and Purification of Folded rDer p 20, the Arginine Kinase From Dermatophagoides pteronyssinus: A Possible Biomarker for Allergic Asthma.

Arginine kinase (AK) was first identified as an allergen in the Indian-meal moth and subsequently shown to occur as allergen in various invertebrates and shellfish. The cDNA coding for AK from the house dust mite (HDM) species Dermatophagoides pteronyssinus, Der p 20, has been isolated, but no recombinant Der p 20 (rDer p 20) allergen has been produced and characterized so far. We report the expression of Der p 20 as recombinant protein in Escherichia coli. rDer p 20 was purified and shown to be a monomeric, folded protein by size exclusion chromatography and circular dichroism spectroscopy, respectively. Using AK-specific antibodies, Der p 20 was found to occur mainly in HDM bodies, but not in fecal particles. Thirty percent of clinically well-characterized HDM allergic patients (n = 98) whose immunoglobulin E (IgE) reactivity profiles had been determined with an extensive panel of purified HDM allergens (Der f 1, 2; Der p 1, 2, 4, 5, 7, 10, 11, 14, 15, 18, 21, 23 and 37) showed IgE reactivity to Der p 20. IgE reactivity to Der p 20 was more frequently associated with lung symptoms. AKs were detected in several invertebrates with specific antibodies and Der p 20 showed IgE cross-reactivity with AK from shrimp (Litopenaeus vannamei). Thus, Der p 20 is a cross-reactive HDM allergen and may serve as a diagnostic marker for HDM-induced lung symptoms such as asthma.

B Cell Functions in the Development of Type I Allergy and Induction of Immune Tolerance.

B cells are key players in the mechanisms underlying allergic sensitization, allergic reactions, and tolerance to allergens. Allergen-specific immune responses are initiated when peptide:MHCII complexes on dendritic cells are recognized by antigen-specific receptors on T cells followed by interactions between costimulatory molecules on the surfaces of B and T cells. In the presence of IL-4, such T-B cell interactions result in clonal expansion and isotype class-switching to IgE in B cells, which will further differentiate into either memory B cells or PCs. Allergic reactions are then triggered upon cross-linking of IgE-FcɛRI complexes on basophils and mast cells, leading to cell degranulation and the release of pro-inflammatory mediators.Mechanisms underlying effective allergen-specific immunotherapy (AIT) involve the induction of Tregs and the secretion of blocking IgG4 antibodies, which together mediate the onset and maintenance of immune tolerance towards non-hazardous environmental antigens. However, the importance of regulatory B cells (Breg) for tolerance induction during AIT has gained more attention lately. Studies in grass pollen- and house dust mite-allergic patients undergoing SCIT reported increased frequencies of IL-10+ Breg cells and a positive correlation between their number and the improvement of clinical symptoms. Thus, Breg are emerging as biomarkers for monitoring tolerance to allergens under natural exposure conditions and during AIT. Further research on the role of other anti-inflammatory cytokines secreted by Breg will help to understand their role in disease development and tolerance induction.

Dendritic cell-CD4+ T cell interaction: The differential role of IL-4/IL-13 in serum IgE levels in house dust mite allergic patients.

Allergic asthma is a chronic airway inflammatory disorder triggered by inhalant allergens. Interleukin (IL)-4 and IL-13 play a main role in the generation of T helper cell type 2 (Th2) immune response, induction of immunoglobulin E (IgE) synthesis and persistence of airway inflammation. The aim of the present study was to investigate the influence of Dermatophagoides pteronyssinus allergen Der p 1, the major allergen of house dust mite, on the synthesis of IL-4 and IL-13 by monocyte-derived dendritic cells (DCs) and naive CD4+ T cells cocultured with DCs, as well as their role in the production of serum IgE, in house dust mite (HDM) allergic patients. Peripheral blood mononuclear cells (PBMCs) were isolated from venous blood of patients allergic to HDM and healthy donors and incubated with granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-4 to generate immature DCs. The obtained cells were stimulated for 24 h with Der p 1 to induce DC maturation, washed, and afterwards cocultured for 24 h with autologous naive CD4+ T cells. Culture supernatants were harvested for IL-4, IL-13 and IFN-γ level measurements. DCs stimulation with Der p 1 induced higher synthesis of IL-4 and IL-13 in HDM allergic patients, compared to healthy donors. The allergic group showed significant correlation between IL-13 production by Der p 1-pulsed DCs, and total serum IgE and IL-4 production of the same cells and Der p-specific IgE. To conclude, IL-4 and IL-13 are critically related to the regulation of serum IgE production in patients with allergic asthma. The relevance of these two cytokines in the pathophysiology of Th2 asthma endotype makes them an appropriate target in its management.

Mapping Human Monoclonal IgE Epitopes on the Major Dust Mite Allergen Der p 2

IgE Abs drive the symptoms of allergic disease upon cross-linking allergens on mast cells or basophils. If the IgE binding sites on the allergens could be identified, it may be useful for creating new forms of immunotherapy. However, direct knowledge of the human IgE (hIgE) epitopes is limited because of the very low frequency of IgE-producing B cells in blood. A new hybridoma technology using human B cells from house dust mite-allergic patients was used to identify four Der p 2-specific hIgE mAbs. Their relative binding sites were assessed and compared by immunoassays with three previously studied murine IgG mAbs. Immunoassays showed that the recognition of Der p 2 by the first three hIgE was inhibited by a single murine IgG, but the fourth hIgE recognized a different epitope from all the other mAbs. The functional ability of the hIgE that bind different epitopes to cross-link Der p 2 was demonstrated in a mouse model of passive systemic anaphylaxis. Nuclear magnetic resonance analyses of Der p 2 in complex with IgG and IgE Abs were used to identify specific residues in the epitopes. To our knowledge, the combination of immunoassays to distinguish overlapping epitopes and nuclear magnetic resonance analyses to identify specific residues involved in Ab binding provided the first epitope mapping of hIgE mAbs to an allergen. The technologies developed in this study will be useful in high-resolution mapping of human epitopes on other Ags and the design of improved therapeutics.

House dust mite allergy and shrimp allergy: a complex interaction.

Background and Objective. Sensitization and allergy to shrimp among Italian house dust mite allergic patients are not well defined and were investigated in a large multicenter study. Methods. Shrimp sensitization and allergy were assessed in 526 house dust mite (HDM)-allergic patients submitted to the detection of IgE to Der p 10 and 100 atopic control not sensitized to HDM. Results. Shrimp allergy occurred in 9% of patients (vs 0% of 100 atopic controls not sensitized to HDM; p minor 0.001). Shrimp-allergic patients were less frequently hypersensitive to airborne allergens other than HDM than crustacean-tolerant subjects (35% vs 58.8%; p minor 0.005). Only 51% of tropomyosin-sensitized patients had shrimp allergy, and these showed significantly higher Der p 10 IgE levels than shrimp-tolerant ones (mean 22.2 KU/l vs 6.2 KU/l; p minor 0.05). Altogether 53% of shrimp-allergic patients did not react against tropomyosin. Conclusions. Shrimp allergy seems to occur uniquely in association with hypersensitivity to HDM allergens and tropomyosin is the main shrimp allergen but not a major one, at least in Italy. Along with tropomyosin-specific IgE levels, monosensitization to HDM seems to represent a risk factor for the development of shrimp allergy among HDM allergic patients.

Sensitization to major Dermatophagoides pteronyssinus allergens in house dust mite allergic patients from North Eastern Poland developing rhinitis or asthma

PurposeRecognition of individual allergens by IgE is crucial for triggering symptoms in allergic rhinitis (AR) or asthmatic (AA) patients. House dust mite (HDM) allergy is frequent around the world, the sensitization profile to individual HDM allergens varies in individual HDM-allergic patients (APs). The aim of this study was to evaluate the pattern of IgE sensitization to three major Dermatophagoides pteronyssinus (Dp) allergens among patients from North Eastern Poland suffering from HDM-AR and/or AA. Patients and methodsThe study was performed on 323 HDM-AR and/or AA patients and 106 controls (CG) including 30 healthy non-atopic subjects, 32 AR patients not sensitized to Dp and 44 non-atopic asthmatics. IgE levels to natural (n)Der p 1, nDer p 2, recombinant (r)Der p 2.0101 and rDer p 23 allergens were measured by ELISA. ResultsThe majority of HDM-APs were sensitized to nDer p 1 (72.1%), nDer p 2 (81.7%), rDer p 2.0101 (78.3%) and rDer p 23 (70.9%). The frequency of positive results to individual allergens depended on clinical manifestations and the level of IgE to the whole Dp extract. In HDM-AA patients, reactivity to nDer p 1 and rDer p 23 was detected more frequently than in HDM-AR patients. The whole Dp extract completely inhibited IgE binding to nDer p 1 and nDer p 2 but only partially to rDer p 23. ConclusionsHDM-APs from North-Eastern Poland display sensitization profile to major allergens which is similarly observed in western Europe. HDM-based diagnostic and therapeutic products should include all major allergens.

IgE and IgG4 responses to shrimp allergen tropomyosin and its epitopes in patients from coastal areas of northern China.

Sensitization to allergens and their peptides varies among patients due to geographical or ethnic differences. The present study aimed to investigate immunoglobulin (Ig)E and IgG4 responses to tropomyosin and its peptides in shrimp allergic patients from northern China. A total of 92 subjects were studied, including 35 shrimp allergic patients, 29 patients with house dust mite (HDM) and/or cockroach allergic patients and 28 healthy volunteers. Serum IgE and IgG4 antibodies to recombinant shrimp tropomyosin (rPen a 1) and its peptides were measured by means of a light-initiated chemiluminescent assay. A total of 9 major sequential epitopes of Pen a 1 reported in the literature were synthesized. Of 35 shrimp allergic patients, 25 (71.4%) had positive Pen 1-specific IgE (sIgE) antibodies and 22 (62.9%) contained measurable rPen a 1-specific IgG4 (sIgG4) antibodies. A strong IgG4 response accompanied the presence of IgE to Pen a 1. None of the patients with HDM and/or cockroach allergy demonstrated IgE reactivity to rPen a 1. The reaction frequency of IgE binding epitope was 20–48%, while that of IgG4 binding epitope was 63.6–3.9%. The IgE and IgG4 recognition patterns of the tropomyosin peptides demonstrated high interpatient heterogeneity. Diversity of IgE binding epitopes was positively correlated with Pen a 1 sIgE levels. In the study population, tropomyosin was a major allergen recognized by the majority of shrimp allergic patients, which is consistent with previous reports. However, none of the 9 epitopes are major (reaction frequency >50%) IgE-binding regions, indicating the epitopes profile may be different in other regions.