Cosensitization to the 3 Nonhomologous Major Cashew Allergens Ana o 1, Ana o 2, and Ana o 3 Is Caused by IgE Cross-reactivity

BACKGROUND

Cashew nuts often cause strong allergic reactions, which are even more severe than those of peanuts. Ana o 1 (vicilin), Ana o 2 (legumin), and Ana o 3 (2S albumin) are major cashew allergens. Cosensitization to all 3 nonhomologous cashew nut allergens has been observed. We hypothesize that this might be due to IgE cross-reactivity.

METHODS

IgE cross-inhibitions were performed with Ana o 1-3 using serum samples from cashew nut-allergic patients. The related hazelnut allergens Cor a 11, 9, and 14 were used as controls. For comparison, IgE cross-reactivity between the hazelnut allergens was investigated using serum samples from hazelnut-allergic patients.

RESULTS

The median percentages of cross-inhibition between Ana o 1, 2, and 3 were 84%-99%. In comparison, the median cross- inhibition values between hazelnut allergens were 33%-62%. The IC50 values revealed the highest IgE affinity to be to Ana o 3 and Cor a 14. Hazelnut legumin Cor a 9 inhibited IgE binding to Ana o 1, 2, and 3, with median percentages of 75%, 56%, and 48%, respectively. No cross-reactivity was observed between allergenic vicilins or between 2S albumins from cashew and hazelnut. Potentially cross-reactive peptides of Ana o 3 identified in silico overlapped with previously reported IgE epitopes of all 3 allergens.

CONCLUSION

IgE with high affinity to Ana o 3 that cross-reacts with the other 2 major nonhomologous cashew nut allergens might be responsible for the high allergenic potency of cashew nut. These cross-reactive IgE types comprise the major fraction of specific IgE in cashew-allergic patients and might be responsible for cross-reactivity between unrelated tree nuts.

Standardization of clinical outcomes used in allergen immunotherapy in allergic asthma: An EAACI position paper

INTRODUCTION

In allergic asthma patients, one of the more common phenotypes might benefit from allergen immunotherapy (AIT) as add-on intervention to pharmacological treatment. AIT is a treatment with disease-modifying modalities, the evidence for efficacy is based on controlled clinical trials following standardized endpoint measures. However, so far there is a lack of a consensus for asthma endpoints in AIT trials. The aim of a task force (TF) of the European Academy of Allergy and Clinical Immunology (EAACI) is evaluating several outcome measures for AIT in allergic asthma.

METHODS

The following domains of outcome measures in asthmatic patients have been evaluated for this position paper (PP): (i) exacerbation rate, (ii) lung function, (iii) ICS withdrawal, (iv) symptoms and rescue medication use, (v) questionnaires (PROMS), (vi) bronchial/nasal provocation, (vii) allergen exposure chambers (AEC) and (viii) biomarkers.

RESULTS

Exacerbation rate can be used as a reliable objective primary outcome; however, there is limited evidence due to different definitions of exacerbation. The time after ICS withdrawal to first exacerbation is considered a primary outcome measure. Besides, the advantages and disadvantages and clinical implications of further domains of asthma endpoints in AIT trials are elaborated in this PP.

CONCLUSION

This EAACI-PP aims to highlight important aspects of current asthma measures by critically evaluating their applicability for controlled trials of AIT.

[Allergy Diagnostics 2021]

Allergic diseases are among the most common diseases worldwide. For appropriate management knowledge of the allergy trigger is crucial. The clinical picture of allergic diseases is diverse and correct diagnosis is often a challenge. The allergist needs to distinguish intolerances from allergies and infectious diseases from non-infectious triggers. Test results have to be interpreted accordingly to differentiate sensitizations from allergies. In this review current state of the art diagnostic measures to diagnose type I and type IV allergies are described and discussed.Immediate type allergies such as allergic rhinoconjunctivitis, asthma and anaphylaxis are mediated by allergen-specific IgE antibodies detectable both in serum and tissue. Typical triggers are pollen, mites, animal epithelia, food, insect toxins and pharmaceuticals. In everyday practice, diagnostics are based on three complementary pillars: the allergy-specific anamnesis as a prerequisite of correct interpretation of subsequent diagnostic tests like skin testing and serological immunoglobulin detection. These can be supplemented as required and available by provocation tests to prove clinical reactivity and cellular assays to demonstrate the cellular immune response.Type IV allergic reactions are mediated by T cells causing contact allergy with a local eczematous reaction with a latency of several hours to days. Some 3,500 triggers, often from occupational environment, are known; e. g., nickel, chromium, cobalt, fragrances, rubber, plastics, preservatives, dyes, neomycin, benzocaine, sulfonamides, quinidine, wool wax, perubalsam, eye therapeutics, light filter substances, disinfectants, pesticides, technical oils or plants. Diagnosis of contact allergy combines the history of cutaneous exposure with associated symptoms and patch testing, with detection of a late phase clinical reaction after 6 to 48, up to a maximum of 96 hours after antigen contact.

IgE reactivity patterns in Asian and central European cockroach-sensitized patients reveal differences in primary sensitizing allergen sources

Background

The prevalence of cockroach (CR) sensitization and its relevance as a trigger of allergy symptoms differs greatly in different geographic areas.

Objective

This study aimed to compare molecular IgE reactivity profiles in CR-sensitized patients with perennial allergy symptoms from Hong Kong (HK) and Austria and identify the main primary sensitizers.

Methods

IgE sensitization was assessed by skin prick test and/or IgE reactivity with CR extract. Molecular IgE reactivity profiles were analyzed via multiplex assay for sensitization to allergens and extracts from CR, house dust mite (HDM), shellfish, and 3 additional insect species.

Results

HDM was the main primary sensitizer in both cohorts. In the HK group, genuine sensitization to CR was found in 45%, but none of the patients in the Austrian cohort was truly sensitized to that allergen source. Most patients from HK were cross-sensitized to other insects and/or shellfish, presumably by broad reactivity to tropomyosin and arginine kinase. About half of Austrian subjects lacked IgE to these pan-allergens, indicating co- but not cross-sensitization to insects and/or shellfish. Regarding IgE recognition frequencies, arginine kinases (64% HK, 10% Austria) and tropomyosins (42% HK, 15% Austria) were most frequently recognized; Bla g 4 (lipocalin) was detected in HK patients only (42%). Tropomyosin (Per a 7) was significantly more frequently recognized in patients with asthma. Sera from HDM-sensitized subjects from HK showed a higher proportion of sensitization to minor mite allergens.

Conclusion

Molecular profiling identified differences between CR-sensitized allergic patients from HK and Austria in terms of primary sensitizers and molecular IgE reactivity patterns. Tropomyosin from American cockroach (Per a 7) was shown to be significantly associated with asthma symptoms and might be suitable as biomarker for more severe respiratory allergy symptoms.

Development and validation of combined symptom-medication scores for allergic rhinitis

BACKGROUND

Validated combined symptom-medication scores (CSMSs) are needed to investigate the effects of allergic rhinitis treatments. This study aimed to use real-life data from the MASK-air^® app to generate and validate hypothesis- and data-driven CSMSs.

METHODS

We used MASK-air^® data to assess the concurrent validity, test-retest reliability and responsiveness of one hypothesis-driven CSMS (modified CSMS: mCSMS), one mixed hypothesis- and data-driven score (mixed score), and several data-driven CSMSs. The latter were generated with MASK-air^® data following cluster analysis and regression models or factor analysis. These CSMSs were compared with scales measuring (i) the impact of rhinitis on work productivity (visual analogue scale [VAS] of work of MASK-air^® , and Work Productivity and Activity Impairment: Allergy Specific [WPAI-AS]), (ii) quality-of-life (EQ-5D VAS) and (iii) control of allergic diseases (Control of Allergic Rhinitis and Asthma Test [CARAT]).

RESULTS

We assessed 317,176 days of MASK-air^® use from 17,780 users aged 16-90 years, in 25 countries. The mCSMS and the factor analyses-based CSMSs displayed poorer validity and responsiveness compared to the remaining CSMSs. The latter displayed moderate-to-strong correlations with the tested comparators, high test-retest reliability and moderate-to-large responsiveness. Among data-driven CSMSs, a better performance was observed for cluster analyses-based CSMSs. High accuracy (capacity of discriminating different levels of rhinitis control) was observed for the latter (AUC-ROC = 0.904) and for the mixed CSMS (AUC-ROC = 0.820).

CONCLUSION

The mixed CSMS and the cluster-based CSMSs presented medium-high validity, reliability and accuracy, rendering them as candidates for primary endpoints in future rhinitis trials.

Technical standards in allergen exposure chambers worldwide - an EAACI Task Force Report

Allergen exposure chambers (AECs) can be used for controlled exposure to allergenic and non-allergenic airborne particles in an enclosed environment, in order to (i) characterize the pathological features of respiratory diseases and (ii) contribute to and accelerate the clinical development of pharmacological treatments and allergen immunotherapy for allergic disease of the respiratory tract (such as allergic rhinitis, allergic rhinoconjunctivitis, and allergic asthma). In the guidelines of the European Medicines Agency for the clinical development of products for allergen immunotherapy (AIT), the role of AECs in determining primary endpoints in dose-finding Phase II trials is emphasized. Although methodologically insulated from the variability of natural pollen exposure, chamber models remain confined to supporting secondary, rather than primary, endpoints in Phase III registration trials. The need for further validation in comparison with field exposure is clearly mandated. On this basis, the European Academy of Allergy and Clinical Immunology (EAACI) initiated a Task Force in 2015 charged to gain a better understanding of how AECs can generate knowledge about respiratory allergies and can contribute to the clinical development of treatments. Researchers working with AECs worldwide were asked to provide technical information in eight sections: (i) dimensions and structure of the AEC, (ii) AEC staff, (iii) airflow, air processing, and operating conditions, (iv) particle dispersal, (v) pollen/particle counting, (vi) safety and non-contamination measures, (vii) procedures for symptom assessments, (viii) tested allergens/substances and validation procedures. On this basis, a minimal set of technical requirements for AECs applied to the field of allergology is proposed.

IgE recognition of the house dust mite allergen Der p 37 is associated with asthma

BACKGROUND

House dust mite (HDM) allergens are major elicitors of allergic reactions worldwide.

OBJECTIVE

Identification, characterization, and evaluation of diagnostic utility of a new important HDM allergen was performed.

METHODS

A cDNA coding for a new Dermatophagoides pteronyssinus (Dp) allergen, Der p 37, was isolated from a Dp expression library with allergic patients' IgE antibodies. Recombinant Der p 37 (rDer p 37) expressed in Escherichia coli was purified, then characterized by mass spectrometry, circular dichroism, and IgE reactivity by ImmunoCAP ISAC technology with sera from 111 clinically defined HDM-allergic patients. The allergenic activity of rDer p 37 was studied by basophil activation and CD4⁺ T-cell responses by carboxyfluorescein diacetate succinimidyl ester dilution assays. Specific antibodies raised against rDer p 37 were used for the ultrastructural localization of Der p 37 in mites by immunogold transmission electron microscopy.

RESULTS

Der p 37, a 26 kDa allergen with homology to chitin-binding proteins, is immunologically distinct from Der p 15, 18, and 23. It is located in the peritrophic membrane of fecal pellets. Der p 37 reacted with IgE antibodies from a third of HDM-allergic patients and induced specific basophil- and CD4⁺ T-cell activation. Der p 37 IgE-positive patients had significantly higher IgE levels to major HDM allergens, reacted with more HDM allergens, and had a higher risk (odds ratio = 3.1) of asthma compared to Der p 37-negative patients.

CONCLUSIONS

Der p 37, a new Dp allergen recognized by a third of HDM-allergic patients, may serve as a surrogate marker for severe HDM sensitization and asthma.

Answers to burning questions for clinical allergologists related to the new COVID-19 vaccines

Background

Along with the newly approved vaccines against coronavirus disease 2019 (COVID-19), first reports of allergic or intolerance reactions were published. Subsequently, questions arose whether these vaccines pose an increased risk for intolerance reactions and whether allergic patients may be at higher risk for this.

Results

Allergic reactions following COVID-19 vaccinations have been reported, but mostly of mild severity and at normal (Moderna®) or only slightly increased frequency (BioNTech/Pfizer®) compared to established conventional vaccines. The risk of allergic reaction to the newly licensed vector vaccines (AstraZeneca®, Johnson&Johnson®) cannot be conclusively assessed yet, but also appears to be low. There is currently no evidence that patients with allergic diseases (atopic patients) react more frequently or more severely to these vaccines. It is currently assumed that intolerance reactions of the immediate-type are either type I allergic (IgE-mediated) reactions or occur via complement activation (CARPA, “complement activation-related pseudoallergy”). Polyethylene glycol (PEG) or polysorbate, which are present as stabilizers in the vaccines, are suspected as triggers for this.

Conclusion

The data available so far do not show a significantly increased risk of immediate-type allergic reactions in atopic persons. In almost all cases, atopic patients can be vaccinated without problems. Standardized follow-up tests after suspected allergic reactions or CARPA-mediated reactions are currently limited.

Burden of allergic rhinitis and impact of MP-AzeFlu from the patient perspective: pan European patient survey

OBJECTIVE

The aims of this survey were to (1) assess the burden of allergic rhinitis (AR) from the patient perspective, (2) investigate MP-AzeFlu use in real life and its impact on patients' lives and (3) explore factors associated with treatment satisfaction.

METHODS

A cross-sectional, quantitative, online, questionnaire-based survey was conducted in seven European countries (March-June 2019). Questions explored AR burden and treatment satisfaction. Satisfaction was assessed using the Treatment Satisfaction Questionnaire for Medication 9-item (TSQM-9; max score = 100). Participants (aged ≥18 years) had a doctor/healthcare provider confirmed AR diagnosis and used MP-AzeFlu within the last year.

RESULTS

Pre-MP-AzeFlu treatment, participants (n = 1004) reported an average of 3.3 (SD:3.5) doctor visits/year, 8.1 (SD:11.0) days/year absenteeism and 15.8 (SD:18.9) days/year presenteeism due to AR. Only 48% of participants used MP-AzeFlu twice/day as recommended. Post-MP-AzeFlu 57% of participants reported better QoL, 47% reported fewer doctor visits and 52% discontinued polypharmacy. Absenteeism and presenteeism were reduced by 2.5 (SD 10.0) and 7.3 (SD:16.0) days/year, respectively. 70% of participants were more/much more satisfied with MP-AzeFlu versus previous AR treatment(s), and ≥70% were satisfied/extremely satisfied with its ability to prevent/treat AR, relieve symptoms and with its onset of action. Mean global, effectiveness and convenience TSQM-9 scores were 70.0 (SD:19.8), 68.3 (SD:21.6) and 72.7 (SD:20.4), respectively. Treatment satisfaction and effectiveness were significantly improved when MP-AzeFlu was taken as recommended.

CONCLUSIONS

The impact of AR on patients' lives remains high. Real-life use of MP-AzeFlu reduces that impact and is associated with a high level of effectiveness, convenience and global satisfaction.

IgE Epitopes of the House Dust Mite Allergen Der p 7 Are Mainly Discontinuous and Conformational

Background

Several studies indicate that Der p 7 is an important and clinically relevant allergen of Dermatophagoides pteronyssinus which should be included in vaccines for treatment of house dust mite (HDM) allergy. Aim of this study was to characterize the IgE epitopes of Der p 7.

Methods

Recombinant Der p 7 was expressed and purified, analyzed for fold by circular dichroism and tested for its allergenic activity by basophil activation. Seven overlapping, surface-exposed peptides (P1–P7) with a length of 27 to 37 amino acids, which spanned the Der p 7 sequence, were synthesized and tested for IgE reactivity and allergenic activity by basophil activation assay. Carrier-bound peptides were studied for their ability to induce allergen-specific IgG antibodies in rabbits. Peptide-specific antibodies were used to inhibit allergic patients` IgE binding to Der p 7 by ELISA for mapping of IgE epitopes.

Results

rDer p 7 showed high allergenic activity comparable with Der p 5, Der p 21, and Der p 23. None of the seven tested peptides showed any IgE reactivity or allergenic activity when tested with HDM- allergic patients indicating lack of sequential IgE epitopes on Der p 7. IgE inhibition experiments using anti-peptide specific IgGs and molecular modeling enabled us to identify discontinuous, conformational IgE epitopes of Der p 7.

Conclusion and Clinical Relevance

IgE epitopes of Der p 7 belong to the conformational and discontinuous type whereas sequential Der p 7 peptides lack IgE reactivity. It should thus be possible to construct hypoallergenic vaccines for Der p 7 based on carrier-bound allergen peptides.

A meta-analysis on allergen-specific immunotherapy using MCT® (MicroCrystalline Tyrosine)-adsorbed allergoids in pollen allergic patients suffering from allergic rhinoconjunctivitis

BACKGROUND

The World Allergy Organization and the European Academy of Allergy and Clinical Immunology recommend to perform product-specific meta-analyses for allergen-specific immunotherapies because of the high degree of heterogeneity between individual products. This meta-analysis evaluates the efficacy and safety of Glutaraldehyde-modified and MCT® (MicroCrystalline Tyrosine)-adsorbed allergoids (MATA).

METHODS

The databases MEDLINE, LILACS, embase, LIVIVO, Web of Science and Google (Scholar) were searched for publications on MATA up to June 2019. Primary endpoint was the combined symptom and medication score (CSMS). Secondary endpoints were single scores, immunogenicity and improvement of allergic condition. Secondary safety endpoints were the occurrence of side effects. A random effects model was applied with (standardized) mean differences ([S]MDs) including confidence intervals (CI). Heterogeneity was analyzed using the I2 index and publication bias using Egger's test and Funnel plots. Subgroups were analyzed regarding age and asthma status.

RESULTS

Eight randomized double-blind placebo-controlled trials were selected for efficacy and 43 publications for safety analysis. In total, 4531 patients were included in this analysis including eight studies containing data on children and adolescents. AIT with MATA significantly reduced allergic symptoms and medication use with a SMD for CSMS of -0.8 (CI: -1.24, -0.36) in comparison to placebo. Heterogeneity was moderate between the studies. The total symptom score (-1.2 [CI: -2.11, -0.29]) and the total medication score (-2.2 [CI: -3.65, -0.74]) were also significantly reduced after MATA treatment. Patient's condition improved significantly after treatment with MATA, with an odds ratio of 3.05 (CI: 1.90, 4.90) when compared to placebo. The proportion of patients, who developed side effects was 38% (CI: 19%, 57%). No serious side effects occurred. Safety in the subgroups of asthmatic patients, children and adolescents did not differ from the overall patient population.

CONCLUSIONS

This meta-analysis reveals a large body of evidence from publications investigating MATA. MATA significantly improved allergic symptoms and reduced the use of anti-allergic medication in comparison to placebo, with an excellent safety profile. Especially for children and asthmatic patients, the use of MATAs can be considered as safe, because the safety profiles in these groups did not differ from the total patient population.

Personalized medicine for allergy treatment: Allergen immunotherapy still a unique and unmatched model

The introduction of personalized medicine (PM) has been a milestone in the history of medical therapy, because it has revolutionized the previous approach of treating the disease with that of treating the patient. It is known today that diseases can occur in different genetic variants, making specific treatments of proven efficacy necessary for a given endotype. Allergic diseases are particularly suitable for PM, because they meet the therapeutic success requirements, including a known molecular mechanism of the disease, a diagnostic tool for such disease, and a treatment blocking the mechanism. The stakes of PM in allergic patients are molecular diagnostics, to detect specific IgE to single-allergen molecules and to distinguish the causative molecules from those merely cross-reactive, pursuit of patient's treatable traits addressing genetic, phenotypic, and psychosocial features, and omics, such as proteomics, epi-genomics, metabolomics, and breathomics, to forecast patient's responsiveness to therapies, to detect biomarker and mediators, and to verify the disease control. This new approach has already improved the precision of allergy diagnosis and is likely to significantly increase, through the higher performance achieved with the personalized treatment, the effectiveness of allergen immunotherapy by enhancing its already known and unique characteristics of treatment that acts on the causes.

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.

Quantification, epitope mapping and genotype cross-reactivity of hepatitis B preS-specific antibodies in subjects vaccinated with different dosage regimens of BM32

Background

Chronic hepatitis B virus (HBV) infections are a global health problem. There is a need for therapeutic strategies blocking continuous infection of liver cells. The grass pollen allergy vaccine BM32 containing the preS domain of the large HBV surface protein (LHBs) as immunogenic carrier induced IgG antibodies in human subjects inhibiting HBV infection in vitro. Aim of this study was the quantification, epitope mapping and investigation of HBV genotype cross-reactivity of preS-specific antibodies in subjects treated with different dosage regimens of BM32

Methods

Hundred twenty eight grass pollen allergic patients received in a double-blind, placebo-controlled trial five monthly injections of placebo (aluminum hydroxide, n= 34) or different courses of BM32 (2 placebo + 3 BM32, n= 33; 1 placebo + 4 BM32, n= 30; 5 BM32, n= 31). Recombinant Escherichia coli-expressed preS was purified. Overlapping peptides spanning preS and the receptor-binding sites from consensus sequences of genotypes A–H were synthesized and purified. Isotype (IgM, IgG, IgA, IgE) and IgG subclass (IgG₁-IgG₄) responses to preS and peptides were determined by ELISA at baseline, one and four months after the last injection. IgG₁ and IgG₄ subclass concentrations specific for preS and the receptor-binding site were measured by quantitative ELISA.

Findings

Five monthly injections induced the highest levels of preS-specific IgG consisting mainly of IgG₁ and IgG₄, with a sum of median preS-specific IgG₁ and IgG₄ concentrations of >135 μg/ml reaching up to 1.8 mg/ml. More than 20% of preS-specific IgG was directed against the receptor-binding site. BM32-induced IgG cross-reacted with the receptor-binding domains from all eight HBV genotypes A-H.

Interpretation

BM32 induces high levels of IgG₁ and IgG₄ antibodies against the receptor binding sites of all eight HBV genotypes and hence might be suitable for therapeutic HBV vaccination.

Funding

This study was supported by the PhD program IAI (KPW01212FW), by Viravaxx AG and by the Danube-ARC funded by the Government of Lower Austria. Rudolf Valenta is a recipient of a Megagrant of the Government of the Russian Federation, grant No 14.W03.31.0024.

Allergen exposure chambers: implementation in clinical trials in allergen immunotherapy

Allergen exposure chambers (AECs) have been developed for controlled allergen challenges of allergic patients mimicking natural exposure. As such, these facilities have been utilized e.g., for proof of concept, dose finding or the demonstration of onset of action and treatment effect sizes of antiallergic medication. Moreover, clinical effects of and immunological mechanisms in allergen immunotherapy (AIT) have been investigated in AECs. In Europe AIT products have to fulfill regulatory requirements for obtaining market authorization through Phase I to III clinical trials. Multiple Phase II (dose-range-finding or proof-of-concept) trials on AIT products have been performed in AECs. However, they are not accepted by regulatory bodies for pivotal (Phase III) trials and a more thorough technical and clinical validation is requested. Recently, a Position Paper of the European Academy of Allergy and Clinical Immunology (EAACI) has outlined unmet needs in further development of AECs. The following review aims to address some of these needs on the basis of recently published data in the first part, whereas the second part overviews published examples of most relevant Phase II trials in AIT performed in AEC facilities.

Fast effectiveness of a solubilized low-dose budesonide nasal spray in allergic rhinitis

Background

Budesonide, a poorly water‐soluble corticosteroid, is currently marketed as a suspension. Budesolv is a novel aqueous formulation containing dissolved budesonide showing increased local availability in preclinical models. Budesolv contains ~85% less corticosteroid than the marketed comparator.

Objective

The study (EudraCT:2018‐001324‐19) was designed to assess non‐inferiority of Budesolv compared to Rhinocort® Aqua 64 (RA) and early onset of action.

Methods

In a three‐way cross‐over double‐blinded randomized trial, Budesolv 10 was compared to RA and placebo in grass pollen allergic rhinoconjunctivitis volunteers (n = 83 (ITT); n = 75 (PP)). On day 1, participants entered the Vienna Challenge Chamber (VCC) for 6 hours; first treatment took place at 1:45 hours after entry. Participants treated themselves for further 6 days; on day 8, the last treatment was applied before entering the VCC. Subjective symptom scores, nasal airflow and nasal secretion were measured regularly during allergen challenge.

Results

Budesolv 10 was equally effective compared to RA with respect to TNSS and nasal airflow after eight days of treatment with a strongly reduced dose (more than 80% reduction). After first dose, only Budesolv 10 showed a significant reduction of nasal and respiratory symptoms starting 90 minutes (P < .05) and 15 minutes (P < .05) after application onwards, respectively, demonstrating an early onset of efficacy. A clinically significant 1 point reduction in nasal symptom score was reached at 195 minutes (P < .05) after application.

Conclusions and clinical relevance

The novel preservative‐free, aqueous low‐dose budesonide formulation is highly efficacious even after an initial single treatment. Thus, Budesolv 10 appears to be an effective acute treatment for allergic rhinitis as well as for AR comorbidities like mild asthma and conjunctivitis.

The Role of Der p 23 Sensitization: An Analysis of 474 Patients Sensitized to Mite

INTRODUCTION

House dust mite contains several allergen components and causes perennial allergy. Lately, a new major allergen, Der p 23, was described with relatively high sensitization rates in different European Countries. In addition, Der p 23 is supposed to cause asthmatic disease.

OBJECTIVE

We would like to question the prevalence and clinical impact of specific immunoglobulin E to Der p 23 in a large patient sample in southern Bavaria, Germany.

METHODS

474 patients from southern Bavaria, who visited the allergy department within the Department of Oto-Rhino-Laryngology of a university hospital, with sensitization to Dermatophagoides pteronyssinus were retrospectively compared regarding their sensitization profile to Der p 1, Der p 2, and Der p 23 and their clinical characteristics.

RESULTS

Among D. pteronyssinus-sensitized patients, the overall sensitization rate to Der p 23 was 42% in southern Bavaria. Most likely, patients were simultaneously sensitized to Der p 1, Der p 2, and Der p 23. Der p 23-sensitized patients reported more frequently asthma and showed higher prevalence of poly-sensitization towards 3 additional allergen groups and higher prevalence of double-sensitization to Der p 1 and Der p 2 compared to patients with missing sensitization to Der p 23. Considering the results of allergen provocation tests, neither IgE sensitization against Der p 23 nor levels of specific immunoglobulin E to Der p 23 allow a clear prediction of the clinical relevance of the sensitization.

CONCLUSION

With a sensitization rate of 42%, Der p 23 closely misses the criterion of a major allergen in our southern Bavarian patient collective. A higher prevalence of polysensitization and self-reported asthma was the only clinical feature found in Der p 23-sensitized patients.

Cetirizine inhibits gender-specific blood cell dynamics upon allergen contact in allergic rhinitis

IgE-mediated inflammatory responses upon allergen contact in allergic rhinitis (AR) are associated with rapid alterations of circulating blood cell numbers detectable in a complete blood count (CBC). Aim of this study was to evaluate whether intake of antihistamines may modulate allergen-induced CBC dynamics in male and female patients. A total of N = 112 specific allergen challenges were performed in otherwise healthy AR subjects. Seventy-two (n = 72) subjects received placebo and forty (n = 40) received cetirizine (H1-receptor antagonist) per os prior to allergen exposure in a randomized, double-blind trial at the Vienna Challenge Chamber (VCC); a subgroup of twenty-five (n = 25) subjects received cetirizine and placebo on different study days (parallel group). Blood samples and symptom scores were taken at baseline and immediately after 6 h of airway challenge simulating ambient allergen contact. Female sex was associated with a pronounced circulating monocyte increase (p < .01) and male sex with an eosinophil decrease (p < .05) in the placebo group, but not in cetirizine treated subjects. The significant increase in segmented neutrophils (p < .001) and decrease in circulating erythrocytes (p < .01) upon allergen challenge was less prominent after cetirizine intake in both sexes. A more prominent thrombocyte increase in female subjects (p < .05) was noted upon allergen exposure, regardless of prior cetirizine intake. Cetirizine inhibited the mobilization of neutrophils, lymphocytes and decline in erythrocyte numbers, but did not affect thrombocyte increase upon allergen challenge. It further diminished gender-specific blood cell dynamics. Overall, as reflected in a simple CBC, cetirizine critically diminished immediate and late innate immune responses subsequent to allergen exposure.

Perspectives in allergen immunotherapy: 2019 and beyond

The seventh "Future of the Allergists and Specific Immunotherapy (FASIT)" workshop held in 2019 provided a platform for global experts from academia, allergy clinics, regulatory authorities and industry to review current developments in the field of allergen immunotherapy (AIT). Key domains of the meeting included the following: (a) Biomarkers for AIT and allergic asthma; (b) visions for the future of AIT; (c) progress and data for AIT in asthma and the updates of GINA and EAACI Asthma Guidelines (separated for house dust mite SCIT, SLIT tablets and SLIT drops; patient populations) including a review of clinically relevant endpoints in AIT studies in asthma; (d) regulatory prerequisites such as the "Therapy Allergen Ordinance" in Germany; (e) optimization of trial design in AIT clinical research; (f) challenges planning and conducting phase III (field) studies and the future role of Allergen Exposure Chambers (AEC) in AIT product development from the regulatory point of view. We report a summary of panel discussions of all six domains and highlight unmet needs and possible solutions for the future.

Shortened up-dosing with sublingual immunotherapy drops containing tree allergens is well tolerated and elicits dose-dependent clinical effects during the first pollen season

Background

This study compared a rapid home-based up-dosing schedule for sublingual immunotherapy (SLIT) drops containing tree pollen allergens with two previously established schedules. Furthermore, the clinical effect of the SLIT was investigated with respect to patients’ first pollen season under treatment.

Methods

In this open-label, prospective, patient-preference, non-interventional study, local and systemic reactions were compared between three up-dosing groups using a SLIT formulation containing birch, alder, and hazel pollen extracts (ORALVAC^® Compact Bäume). Clinical improvement after patients’ first season under treatment was analysed using symptom scores, ARIA classification, symptom control, and the use of symptomatic medication and was compared with data from the previous, pre-treatment pollen season. As the real-life study design allowed no placebo group, the late-treated patients (co-seasonal) served as a control, and crowd-sourced symptom data from persons with hay fever were used from a free web-based online diary.

Results

In 33 study centres in Germany and Austria, 164 patients were included. The treatment was well tolerated, without difference between the groups during the up-dosing phase. At the end of the assessment, 96.1% rated the tolerability of the treatment as good or very good. Local reactions were mostly mild in severity and no serious adverse events occurred. Symptom scores decreased from the 2016 pollen season to the 2017 pollen season. As for the ARIA classification, 79.0% of patients had persistent, moderate-to-severe rhinitis before treatment, but only 18.6% had the same classification after treatment. In all, 62.4% of patients achieved symptom control, and 34.3% of patients required no symptomatic medication after treatment. The rhinoconjunctivitis score was 34.4% lower for pre-seasonal treatment initiation than for the control group. Crowd-sourced symptom load indices showed that the 2016 season caused slightly more symptoms; however, it is assumed that this difference of 0.3–0.5 (score range 0–10) was of less clinical relevance.

Conclusion

The treatment administered using the rapid home-based up-dosing schedule was safe and well tolerated. Symptom relief and reduction in medication use were observed during the first pollen season with SLIT.

Trial registration number

NCT03097432 (clinicaltrials.gov).

Clinical efficacy of sublingual immunotherapy is associated with restoration of steady-state serum lipocalin 2 after SLIT: a pilot study

Background

So far, only a few biomarkers in allergen immunotherapy exist that are associated with a clinical benefit. We thus investigated in a pilot study whether innate molecules such as the molecule lipocalin-2 (LCN2), with implications in immune tolerance demonstrated in other fields, may discriminate A) between allergic and non-allergic individuals, and B) between patients clinically responding or non-responding to sublingual allergen immunotherapy (SLIT) with house dust mite (HDM) extract. Moreover, we assessed haematological changes potentially correlating with allergic symptoms.

Methods

LCN2-concentrations were assessed in sera of healthy and allergic subjects (n = 126) as well as of house dust mite (HDM) allergics before and during HDM- sublingual immunotherapy (SLIT) in a randomized, double-blind, placebo-controlled trial for 24 weeks. Sera pre-SLIT (week 0), post-SLIT (week 24) and 9 months after SLIT were assessed for LCN2 levels and correlated with total nasal symptom scores (TNSS) obtained during chamber challenge at week 24 in patients receiving HDM- (n = 31) or placebo-SLIT (n = 10).

Results

Allergic individuals had significantly (p < 0.0001) lower LCN2-levels than healthy controls. HDM-allergic patients who received HDM-SLIT showed a significant increase in LCN2 9 months after termination of HDM-SLIT (p < 0.001), whereas in subjects receiving placebo no increase in LCN2 was observed. Among blood parameters a lower absolute rise in the lymphocyte population (p < 0.05) negatively correlated with symptom improvement (Pearson r 0.3395), and a lower relative increase in the neutrophils were associated with improvement in TNSS (p < 0.05). LCN2 levels 9 months after immunotherapy showed a low positive correlation with the relative improvement of symptoms (Pearson r 0.3293). LCN2-levels 9 months off-SLIT were significantly higher in patients whose symptoms improved during chamber challenge than in those whose symptoms aggravated (p < 0.01).

Conclusion

Serum LCN2 concentrations 9 months off-SLIT correlated with clinical reactivity in allergic patients. An increase in the LCN2 levels 9 months after HDM-SLIT was associated with a clinical benefit. Serum LCN2 may thus contribute to assess clinical reactivity in allergic patients.

Trial registration

Part of the data were generated from clinicaltrials.gov Identifier NCT01644617.

Intranasal administration of allergen increases specific IgE whereas intranasal omalizumab does not increase serum IgE levels-A pilot study

Background

Administration of the therapeutic anti‐IgE antibody omalizumab to patients induces strong increases in IgE antibody levels.

Objective

To investigate the effect of intranasal administration of major birch pollen allergen Bet v 1, omalizumab or placebo on the levels of total and allergen‐specific IgE in patients with birch pollen allergy.

Methods

Based on the fact that intranasal allergen application induces rises of systemic allergen‐specific IgE, we performed a double‐blind placebo‐controlled pilot trial in which birch pollen allergic subjects were challenged intranasally with omalizumab, placebo or birch pollen allergen Bet v 1. Total and allergen‐specific IgE, IgG and basophil sensitivity were measured before and 8 weeks after challenge. For control purposes, total, allergen‐specific IgE levels and omalizumab‐IgE complexes as well as specific IgG levels were studied in subjects treated subcutaneously with either omalizumab or placebo. Effects of omalizumab on IgE production by IL‐4/anti‐CD40‐treated PBMCs from allergic patients were studied in vitro.

Results

Intranasal challenge with Bet v 1 induced increases in Bet v 1‐specific IgE levels by a median of 59.2%, and this change differed significantly from the other treatment groups (P = .016). No relevant change in allergen‐specific and total IgE levels was observed in subjects challenged with omalizumab. Addition of omalizumab did not enhance IL‐4/anti‐CD40‐induced IgE production in vitro. Significant rises in total IgE (mean IgE before: 131.83 kU/L to mean IgE after: 505.23 kU/L) and the presence of IgE‐omalizumab complexes were observed after subcutaneous administration of omalizumab.

Conclusion

Intranasal administration of allergen induced rises of allergen‐specific IgE levels, whereas intranasal administration of omalizumab did not enhance systemic total or allergen‐specific IgE levels.

Perspectives in allergen immunotherapy: 2017 and beyond

The Future of the Allergists and Specific Immunotherapy (FASIT) workshop provides a regular platform for global experts from academia, allergy clinics, regulatory authorities and industry to review developments in the field of allergen immunotherapy (AIT). The most recent meeting, held in February 2017, had two main themes: advances in AIT and hot topics in AIT from the regulatory point of view. The first theme covered opportunities for personalized AIT, advances in adjuvants and delivery systems, and the development of new molecules and future vaccines for AIT. Key topics in the second part of the meeting were the effects of the enactment of European Directive 2001/83 on the availability of allergens for therapy and diagnosis across the EU, the challenges of conducting Phase 3 studies in the field, the future role of allergen exposure chambers in AIT studies and specific considerations in performing AIT studies in the paediatric population. Finally, the group highlighted the forthcoming EAACI guidelines and their particular importance for the standardization of practice in the treatment of allergies. This review presents a comprehensive insight into those panel discussions and highlights unmet needs and also possible solutions to them for the future.

Possible effect of landscape design on IgE recognition profiles of two generations revealed with micro-arrayed allergens

The aim of this study was to investigate possible effects of landscape design on the IgE sensitization profile toward inhalant allergens in patients with respiratory allergy from Uzbekistan where green areas have been changed during the last two decades by a State program. Sera from two different generations of Uzbek (n=58) and, for control purposes, from two generations of Austrian (n=58) patients were analyzed for IgE reactivity to 112 different micro‐arrayed allergen molecules by ImmunoCAP ISAC technology. Changes in molecular IgE sensitization profiles to pollen allergens in the young vs the middle‐aged Uzbek population were associated with replanting, whereas those in the Vienna populations reflected natural changes in plant growth. Our data indicate that anthropologic as well as natural changes in the biome may have effects on IgE sensitization profiles already from one to another generation.

Long-term effects of a house dust mite sublingual immunotherapy tablet in an environmental exposure chamber trial

BACKGROUND

Treatment with SQ house dust mite (HDM) sublingual immunotherapy (SLIT) tablet is effective for HDM respiratory allergic disease, but data on long-term effects are lacking.

OBJECTIVE

Post hoc analyses were conducted to determine the long-term effect of SQ HDM SLIT-tablet on nasal, ocular, and cough symptoms 1 year after discontinuation of treatment.

METHODS

Study participants underwent environmental exposure chamber (EEC) challenges at baseline and week 24 in a randomized, placebo-controlled, double-blind trial (NCT01644617) during which participants received daily 12 SQ-HDM, 6 SQ-HDM, or placebo for 24 weeks. Asthma had to be stable, well controlled, and nonsevere. The mean total asthma symptom score (TASS; sum of 3 symptoms: cough, wheeze, and dyspnea) during baseline and week 24 EEC challenge was analyzed in all participants who completed the trial (n = 106). Approximately 1 year after trial completion, another EEC challenge was conducted in a subset of participants (n = 51). Total nasal symptom score (sum of 4 symptoms), total ocular symptom score (sum of 2 symptoms), and cough were assessed.

RESULTS

Compared with baseline and end-of-treatment values, sustained improvement of all symptoms assessed at the 1-year follow-up EEC challenge was evident in participants treated with 12 SQ-HDM. Results with 6 SQ-HDM were less notable. After 24 weeks of 12 SQ-HDM, TASS during EEC challenge was improved 65% vs baseline; at 1-year follow-up, cough was improved 57% vs baseline.

CONCLUSION

Persistent improvement of nasal and ocular symptoms was observed up to 1 year after completing 24 weeks of 12 SQ-HDM treatment. Beneficial effects on cough were also observed.

TRIAL REGISTRATION

clinicaltrials.gov Identifier NCT01644617.

Allergen exposure chambers: harmonizing current concepts and projecting the needs for the future - an EAACI Position Paper

BACKGROUND

Allergen exposure chambers (AECs) are clinical facilities allowing for controlled exposure of subjects to allergens in an enclosed environment. AECs have contributed towards characterizing the pathophysiology of respiratory allergic diseases and the pharmacological properties of new therapies. In addition, they are complementary to and offer some advantages over traditional multicentre field trials for evaluation of novel therapeutics. To date, AEC studies conducted have been monocentric and have followed protocols unique to each centre. Because there are technical differences among AECs, it may be necessary to define parameters to standardize the AECs so that studies may be extrapolated for driving basic immunological research and for marketing authorization purposes by regulatory authorities.

METHODS

For this task force initiative of the European Academy of Allergy and Clinical Immunology (EAACI), experts from academia and regulatory agencies met with chamber operators to list technical, clinical and regulatory unmet needs as well as the prerequisites for clinical validation.

RESULTS

The latter covered the validation process, standardization of challenges and outcomes, intra- and interchamber variability and reproducibility, in addition to comparability with field trials and specifics of paediatric trials and regulatory issues.

CONCLUSION

This EAACI Position Paper aims to harmonize current concepts in AECs and to project unmet needs with the intent to enhance progress towards use of these facilities in determining safety and efficacy of new therapeutics in the future.

Sublingual house dust mite immunotherapy has no impact on decrease of circulating erythrocytes upon airway allergen challenge in allergic rhinitis

House dust mite (HDM) allergy is a predominant cause for perennial allergic rhinitis (AR) in Europe. We recently reported that circulating erythrocyte numbers decrease after airway allergen challenge in a murine asthma model and in grass-pollen sensitized AR subjects. Consequently, we aimed to evaluate these findings in HDM sensitized AR subjects and the influence of preceding allergen immunotherapy. Seventy-seven (age 26.8 ± 7.3 years; 54.5% female) HDM-allergic rhinitis subjects previously enrolled in a randomized, monocentric sublingual immunotherapy (SLIT) trial at the Vienna Challenge Chamber (VCC) were included. Subjects had either received placebo (n = 22), low-dose HDM (n = 29) or high-dose HDM specific sublingual immunotherapy (n = 26) daily for 24 weeks. Blood sampling was performed before and after 6 hours of HDM allergen exposure. Overall, specific airway allergen challenge resulted in a significant decrease in circulating erythrocytes and hematocrit (p < 0.001), and elevation of leukocytes (p < 0.001), particularly segmented neutrophils (p < 0.001). Gender had no significant effect on the observed changes in circulating blood cells. Erythrocytes decreased and neutrophil counts increased significantly after airway allergen challenge regardless of preceding immunotherapy. These findings imply a rapid systemic mobilization of neutrophils occurring within immediate type hypersensitivity response upon a specific allergen challenge, which is possibly inversely linked with the erythrocyte numbers.

Mechanisms, safety and efficacy of a B cell epitope-based vaccine for immunotherapy of grass pollen allergy

BACKGROUND

We have developed a recombinant B cell epitope-based vaccine (BM32) for allergen-specific immunotherapy (AIT) of grass pollen allergy. The vaccine contains recombinant fusion proteins consisting of allergen-derived peptides and the hepatitis B surface protein domain preS as immunological carrier.

METHODS

We conducted a randomized, double-blind, placebo-controlled AIT study to determine safety, clinical efficacy and immunological mechanism of three subcutaneous injections of three BM32 doses adsorbed to aluminum hydroxide versus aluminum hydroxide (placebo) applied monthly to grass pollen allergic patients (n=70). Primary efficacy endpoint was the difference in total nasal symptom score (TNSS) through grass pollen chamber exposure before treatment and 4weeks after the last injection. Secondary clinical endpoints were total ocular symptom score (TOSS) and allergen-specific skin response evaluated by titrated skin prick testing (SPT) at the same time points. Treatment-related side effects were evaluated as safety endpoints. Changes in allergen-specific antibody, cellular and cytokine responses were measured in patients before and after treatment.

RESULTS

Sixty-eight patients completed the trial. TNSS significantly decreased with mean changes of -1.41 (BM32/20μg) (P=0.03) and -1.34 (BM32/40μg) (P=0.003) whereas mean changes in the BM32/10μg and placebo group were not significant. TOSS and SPT reactions showed a dose-dependent decrease. No systemic immediate type side effects were observed. Only few grade 1 systemic late phase reactions occurred in BM32 treated patients. The number of local injection site reactions was similar in actively and placebo-treated patients. BM32 induced highly significant allergen-specific IgG responses (P<0.0001) but no allergen-specific IgE. Allergen-induced basophil activation was reduced in BM32 treated patients and addition of therapy-induced IgG significantly suppressed T cell activation (P=0.0063).

CONCLUSION

The B cell epitope-based recombinant grass pollen allergy vaccine BM32 is well tolerated and few doses are sufficient to suppress immediate allergic reactions as well as allergen-specific T cell responses via a selective induction of allergen-specific IgG antibodies. (ClinicalTrials.gov number, NCT01445002.).

Immunotherapy With the PreS-based Grass Pollen Allergy Vaccine BM32 Induces Antibody Responses Protecting Against Hepatitis B Infection

Background

We have constructed and clinically evaluated a hypoallergenic vaccine for grass pollen allergy, BM32, which is based on fusion proteins consisting of peptides from the IgE binding sites of the major grass pollen allergens fused to preS (preS1 + preS2), a domain of the hepatitis B virus (HBV) large envelope protein which mediates the viral attachment and entry. Aim of this study was the characterization of the HBV-specific immune response induced by vaccination of allergic patients with BM32 and the investigation of the vaccines' potential to protect against infection with HBV.

Methods

Hepatitis B-specific antibody and T cell responses of patients vaccinated with BM32 were studied using recombinant preS and synthetic overlapping peptides spanning the preS sequence. The specificities of the antibody responses were compared with those of patients with chronic HBV infection. Furthermore, the capacity of BM32-induced antibodies, to inhibit HBV infection was investigated using HepG2-hNTCP cell-based in vitro virus neutralization assays.

Findings

IgG antibodies from BM32-vaccinated but not of HBV-infected individuals recognized the sequence motif implicated in NTCP (sodium-taurocholate co-transporting polypeptide)-receptor interaction of the hepatitis B virus and inhibited HBV infection.

Interpretation

Our study demonstrates that the recombinant hypoallergenic grass pollen allergy vaccine BM32 induces hepatitis B-specific immune responses which protect against hepatitis B virus infection in vitro.

•

BM32 is a recombinant allergy vaccine consisting of the preS domain of the large envelope protein of hepatitis B virus (HBV) and allergen-derived peptides.

•

Vaccination of allergic patients with BM32 induced preS-specific antibodies which inhibit hepatitis B infection in vitro.

•

BM32 may be useful as therapeutic vaccine in HBV-infected patients.

Infection with HBV remains a major cause of morbidity and mortality worldwide. Conventional HBV vaccines, consisting of SHBs particles solely, do not elicit adequate antibody production in 5–10% of vaccines and there is a need for therapeutic HBV vaccines. We have engineered an allergy vaccine which consists of allergen-derived peptides fused to the preS domain of the large envelope protein of HBV. Here we show that vaccination of allergic patients with this vaccine induces antibodies which protect against HBV infection in vitro. The preS-containing allergy vaccine may thus be also useful for therapeutic vaccination of HBV-infected patients.

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

INTRODUCTION

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

AREAS COVERED

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

Structural and Functional Characterization of the Major Allergen Amb a 11 from Short Ragweed Pollen

Allergy to the short ragweed (Ambrosia artemisiifolia) pollen is a major health problem. The ragweed allergen repertoire has been recently expanded with the identification of Amb a 11, a new major allergen belonging to the cysteine protease family. To better characterize Amb a 11, a recombinant proform of the molecule with a preserved active site was produced in Escherichia coli, refolded, and processed in vitro into a mature enzyme. The enzymatic activity is revealed by maturation following an autocatalytic processing resulting in the cleavage of both N- and C-terminal propeptides. The 2.05-Å resolution crystal structure of pro-Amb a 11 shows an overall typical C1A cysteine protease fold with a network of molecular interactions between the N-terminal propeptide and the catalytic triad of the enzyme. The allergenicity of Amb a 11 was confirmed in a murine sensitization model, resulting in airway inflammation, production of serum IgEs, and induction of Th2 immune responses. Of note, inflammatory responses were higher with the mature form, demonstrating that the cysteine protease activity critically contributes to the allergenicity of the molecule. Collectively, our results clearly demonstrate that Amb a 11 is a bona fide cysteine protease exhibiting a strong allergenicity. As such, it should be considered as an important molecule for diagnosis and immunotherapy of ragweed pollen allergy.

The improved efficacy of a fixed-dose combination of fluticasone furoate and levocabastine relative to the individual components in the treatment of allergic rhinitis

BACKGROUND

Allergic rhinitis (AR) is a common chronic disease, which has significant detrimental effect on well-being and quality of life as well as substantial socio-economic impact. Combination pharmacotherapy is utilized by 40-50% of patients to treat their symptoms.

OBJECTIVE

To compare the effects of intranasal fluticasone furoate (FF)/levocabastine (LEVO) fixed-dose combination (FDC) with each component alone on allergen-induced nasal and ocular symptoms.

METHODS

A randomized, double-blind, placebo-controlled, three-way, incomplete block, cross-over, proof-of-concept study in 71 patients with AR, evaluated FF 100 μg, LEVO 200 μg and FDC (FF 100/LEVO 200 μg), once daily via intranasal spray for 8 days. On days 1 and 8, total nasal symptom score (TNSS) and total ocular symptom score (TOSS) were assessed every 15 min during a 4-h allergen exposure in the Vienna Challenge Chamber. The primary endpoint was Day 8 weighted mean TNSS.

RESULTS

After 8 days, FDC resulted in both statistically and clinically significant reductions in mean TNSS compared with FF and LEVO alone [adjusted mean differences (95% CI): FDC vs. FF: -2.26 (-2.90, -1.62); FDC vs. LEVO: -2.57 (-3.21, -1.93)]. All active treatments were significantly superior to placebo [adjusted mean difference (95% CI) from placebo: FDC: -4.1 (-4.86, -3.34); FF: -1.84 (-2.66, -1.03); LEVO: -1.53 (-2.34, -0.72)]. Onset of action was rapid following FDC and LEVO treatment with an approximate two unit reduction in mean TNSS from pre-dose levels by 30 min and 1 h. Mean TOSS was also reduced following all active treatments relative to placebo (range 0.6-0.8 unit reduction). All treatments were equally well tolerated.

CONCLUSIONS AND CLINICAL RELEVANCE

These results suggest that once daily FF/LEVO FDC could provide a clinical therapeutic advantage to existing standard monotherapies in the treatment of moderate-to-severe AR, and support progression to evaluation in larger phase III clinical studies.

Randomized phase 1 study of the phosphatidylinositol 3-kinase δ inhibitor idelalisib in patients with allergic rhinitis

BACKGROUND

Phosphatidylinositol 3-kinase p110δ isoform (PI3K p110δ) activity is essential for mast cell activation, suggesting that inhibition of PI3K p110δ might be useful in treating allergic diseases.

OBJECTIVE

We sought to determine the effect of the PI3K p110δ-selective inhibitor idelalisib on allergic responses.

METHODS

This phase 1 randomized, double-blind, placebo-controlled, 2-period crossover study was conducted with the Vienna Challenge Chamber. Grass pollen-induced allergic symptoms were documented during screening. Eligible subjects received idelalisib (100 mg twice daily) or placebo for 7 days, with allergen challenge on day 7. After a 2-week washout period, subjects received the alternate treatment and repeated allergen challenge. Study measures included safety, nasal and nonnasal symptoms, nasal airflow, nasal secretions, basophil activation, and plasma cytokine levels.

RESULTS

Forty-one patients with allergic rhinitis received idelalisib/placebo (n = 21) or placebo/idelalisib (n = 20). Idelalisib treatment was well tolerated. Mean total nasal symptom scores were lower during the combined idelalisib treatment periods compared with placebo (treatment difference [idelalisib - placebo], -1.78; 95% CI, -2.53 to -1.03; P < .001). Statistically significant differences were also observed for the combined treatment periods for total symptom scores, nasal airflow, nasal secretion weight, and nasal congestion scores. The percentage of ex vivo-activated basophils (CD63(+)/CCR3(+) cells; after stimulation with grass pollen) was substantially lower for idelalisib-treated compared with placebo-treated subjects. Plasma CCL17 and CCL22 levels were reduced after idelalisib treatment.

CONCLUSION

Idelalisib treatment was well tolerated in patients with allergic rhinitis and appears to reduce allergic responses clinically and immunologically after an environmental allergen challenge.

Epitope specificity determines cross-protection of a SIT-induced IgG4 antibody

Background

The calcium‐binding 2EF‐hand protein Phl p 7 from timothy grass pollen is a highly cross‐reactive pollen pan‐allergen that can induce severe clinical symptoms in allergic patients. Recently, a human monoclonal Phl p 7‐specific IgG₄ antibody (mAb102.1F10) was isolated from a patient who had received grass pollen‐specific immunotherapy (SIT).

Methods

We studied epitope specificity, cross‐reactivity, affinity and cross‐protection of mAb102.1F10 towards homologous calcium‐binding pollen allergens. Sequence comparisons and molecular modelling studies were performed with ClustalW and SPADE, respectively. Surface plasmon resonance measurements were made with purified recombinant allergens. Binding and cross‐reactivity of patients' IgE and mAb102.1F10 to calcium‐binding allergens and peptides thereof were studied with quantitative RAST‐based methods, in ELISA, basophil activation and IgE‐facilitated allergen presentation experiments.

Results

Allergens from timothy grass (Phl p 7), alder (Aln g 4), birch (Bet v 4), turnip rape (Bra r 1), lamb's quarter (Che a 3) and olive (Ole e 3, Ole e 8) showed high sequence similarity and cross‐reacted with allergic patients' IgE. mAb102.1F10 bound the C‐terminal portion of Phl p 7 in a calcium‐dependent manner. It cross‐reacted with high affinity with Ole e 3, whereas binding and affinity to the other allergens were low. mAb102.1F10 showed limited cross‐inhibition of patients' IgE binding and basophil activation. Sequence comparison and surface exposure calculations identified three amino acids likely to be responsible for limited cross‐reactivity.

Conclusions

Our results demonstrate that a small number of amino acid differences among cross‐reactive allergens can reduce the affinity of binding by a SIT‐induced IgG and thus limit cross‐protection.

Effects of nasal corticosteroids on boosts of systemic allergen-specific IgE production induced by nasal allergen exposure

Background

Allergen exposure via the respiratory tract and in particular via the nasal mucosa boosts systemic allergen-specific IgE production. Intranasal corticosteroids (INCS) represent a first line treatment of allergic rhinitis but their effects on this boost of allergen-specific IgE production are unclear.

Aim

Here we aimed to determine in a double-blind, placebo-controlled study whether therapeutic doses of an INCS preparation, i.e., nasal fluticasone propionate, have effects on boosts of allergen-specific IgE following nasal allergen exposure.

Methods

Subjects (n = 48) suffering from grass and birch pollen allergy were treated with daily fluticasone propionate or placebo nasal spray for four weeks. After two weeks of treatment, subjects underwent nasal provocation with either birch pollen allergen Bet v 1 or grass pollen allergen Phl p 5. Bet v 1 and Phl p 5-specific IgE, IgG_1–4, IgM and IgA levels were measured in serum samples obtained at the time of provocation and one, two, four, six and eight weeks thereafter.

Results

Nasal allergen provocation induced a median increase to 141.1% of serum IgE levels to allergens used for provocation but not to control allergens 4 weeks after provocation. There were no significant differences regarding the boosts of allergen-specific IgE between INCS- and placebo-treated subjects.

Conclusion

In conclusion, the application of fluticasone propionate had no significant effects on the boosts of systemic allergen-specific IgE production following nasal allergen exposure.

Trial Registration

http://clinicaltrials.gov/ NCT00755066

Onset and dose-related efficacy of house dust mite sublingual immunotherapy tablets in an environmental exposure chamber

BACKGROUND

The magnitude of effect of sublingual immunotherapy for house dust mite (HDM)-induced allergic rhinitis with or without conjunctivitis is uncertain, partly because there are few well-controlled trials with well-defined doses.

OBJECTIVE

We sought to determine the dose-related efficacy and onset of action of the HDM sublingual immunotherapy tablet MK-8237 (Merck/ALK-Abelló) using the Vienna Challenge Chamber.

METHODS

In this randomized, double-blind, single-site trial, adults with HDM-induced allergic rhinitis with or without conjunctivitis and with or without asthma (n = 124) received 12 developmental units (DU) of MK-8237, 6 DU of MK-8237, or placebo daily for 24 weeks. Subjects underwent 6-hour exposure challenges at screening and weeks 8, 16, and 24. The total nasal symptom score (TNSS) during chamber challenge at week 24 was the primary end point. The TNSS was the sum of 4 nasal symptom scores (maximum = 12). Total ocular symptom scores (TOSSs; 2 symptoms; maximum = 6) and total symptom scores (TSSs; TSS = TNSS plus TOSS; maximum = 18) were secondary end points.

RESULTS

Dose- and time-dependent improvements with MK-8237 versus placebo were observed. At week 24, TNSS improvement relative to placebo was 48.6% (95% CI, 35.3% to 60.2%) with 12 DU of MK-8237 and 26.6% (95% CI, 11.2% to 39.6%) with 6 DU of MK-8237. Statistically significant improvements for TNSSs were also observed at weeks 8 (12 DU of MK-8237) and 16 (6 and 12 DU of MK-8237) and for TOSSs and TSSs by both doses at week 24. MK-8237 was well tolerated. No investigator-assessed anaphylactic allergic reactions or reactions requiring epinephrine were observed.

CONCLUSIONS

MK-8237, 12 DU, reduced nasal and ocular symptoms and exceeded World Allergy Organization-established clinical efficacy criteria (≥20% improvement vs placebo). The onset of action for 12 DU of MK-8237 was week 8. MK-8237, 12 DU, is appropriate for further evaluation to determine the magnitude of effect in an uncontrolled allergen exposure environment.

The CRTH2 antagonist OC000459 reduces nasal and ocular symptoms in allergic subjects exposed to grass pollen, a randomised, placebo-controlled, double-blind trial

BACKGROUND

CRTH2 mediates activation of Th2 cells, eosinophils and basophils in response to prostaglandin D(2). The CRTH2 antagonist OC000459 has previously been demonstrated to reduce airway inflammation and improve lung function in moderate persistent asthma. The objective of the present study was to determine the involvement of CRTH2 in promoting nasal and ocular symptoms in allergic subjects exposed to grass pollen.

METHODS

A single centre, randomised, double-blind, placebo-controlled, two-way crossover study was conducted in 35 male subjects allergic to grass pollen comparing OC000459 200 mg bid with placebo for 8 days. Subjects were exposed to grass pollen (≥ 1400 grains/m(3)) for 6 h on the 2nd and 8th days of treatment and assessed for nasal symptoms, ocular symptoms, other symptoms, nasal secretion weight and rhinomanometry over the 6-h period. After a washout period of 3 weeks, subjects were switched to the alternative treatment for a further 8 days. The trial was registered on the clinical trials.gov database (Identifier NCT01448902).

RESULTS

During the first treatment period, treatment with OC000459 significantly reduced both nasal and ocular symptoms in allergic subjects compared with placebo after challenge with grass pollen. A significant effect was observed on the 2nd day of dosing which was increased on the 8th day of dosing. The therapeutic effects of OC000459 persisted into the second treatment period despite a 3-week washout phase. The safety profile of OC000459 was similar to that of placebo.

CONCLUSION

Treatment with OC000459 was well tolerated and led to a significant and persistent reduction in the symptoms of rhinoconjunctivitis.

Changes in basophil activation during grass-pollen sublingual immunotherapy do not correlate with clinical efficacy

BACKGROUND

Biomarkers predicting the safety and efficacy of sublingual immunotherapy (SLIT) remain to be established.

METHODS

Eighty-nine patients with allergic rhinoconjunctivitis to grass pollen received either a placebo or five-grass-pollen daily tablet sublingually for 4 months. Following exposure in an allergen challenge chamber, clinical responders and nonresponders were identified individually by evaluating their rhinoconjunctivitis total symptom score (RTSS). Activation of peripheral blood basophils was measured by cytofluorometry before and after 2 or 4 months of immunotherapy, based on CD203c surface expression following allergen stimulation.

RESULTS

Patients receiving the grass-pollen tablet had a relative mean improvement of 29.3% vs placebo in the average RTSS after 4 months of SLIT (P < 0.0003). No significant changes in basophil activation were noticed after 2 or 4 months of SLIT despite induction of specific IgGs. Among individual clinical responders, basophil activation was either decreased, increased, or unmodified during SLIT. Levels of basophil activation prior to immunotherapy were not predictive of local adverse reactions associated with immunotherapy. A moderate association was found between basophil activation and allergen-specific IgE levels, skin reactivity, or RTSS, suggesting that the former is, to some extent, indicative of disease severity. As such, patients with the highest level of basophil activation before treatment were more likely to benefit clinically from SLIT.

CONCLUSIONS

Allergen reactivity of peripheral blood basophils is not a biomarker for adverse events or early onset of clinical responses to SLIT.