Diagnostic value of outcome measures following allergen exposure in an environmental challenge chamber compared with natural conditions

Clinical validation of grass pollen exposure chamber in patients with allergic rhinitis triggered by timothy grass

BACKGROUND

The fluctuation in concentrations of airborne allergens frequently presents a challenge to assessing the efficacy of allergen immunotherapy (AIT) in 'field' studies. Allergen exposure chambers (AECs) are specialized medical installations developed to expose individuals to allergens at defined and consistent concentrations under a controlled environment. The aim of the study was to validate the provocation test with timothy grass pollen as well as to assess its safety in the AEC in patients with allergic rhinitis.

METHODS

In the ALLEC® AEC, varying concentrations of timothy grass pollen were dispersed. Allergic symptoms were measured by total nasal symptom score (TNSS), acoustic rhinometry, peak nasal inspiratory flow (PNIF) and nasal discharge volume. Lung function, assessed through peak expiratory flow rate (PEFR) and forced expiratory volume in the first second (FEV1), was used to evaluate safety.

RESULTS

The consistency of the test was proved by the stability of environmental conditions, including temperature, humidity and CO2 levels, as well as constant concentrations of grass pollen at predetermined levels ranging from 1000 to 10,000 particles per cubic meter (p/m3). Allergic individuals developed symptoms at concentrations of 3000 p/m3 and above, across all measured endpoints. Lung function was not affected throughout all the challenges. The reproducibility of symptoms was confirmed throughout the tests. The concentration of 8000 p/m3 together with a challenge duration of 120 min was found to be optimal.

CONCLUSION

The study demonstrates that the ALLEC® grass pollen exposure chamber provides a reliable and safe method for inducing repeatable symptoms in patients with allergic rhinitis. This approach can be effectively applied for allergy diagnostics and clinical endpoint determination during AIT.

Pharmacokinetics of Nasal Esketamine in Patients with Allergic Rhinitis with and Without Nasal Decongestant Pretreatment and in Healthy Subjects with and Without Nasal Corticosteroid Pretreatment

BACKGROUND AND OBJECTIVES

Nasal esketamine is indicated for the treatment of adults with treatment-resistant depression and depressive symptoms in adults with major depressive disorder with acute suicidal ideation or behavior. Primary objectives of this study were to evaluate the effect of nasal decongestant pretreatment in patients with allergic rhinitis and the impact of daily nasal corticosteroid administration by healthy subjects on nasal esketamine pharmacokinetics.

METHODS

Patients with allergic rhinitis self-administered 56 mg of nasal esketamine after pretreatment with nasal oxymetazoline (0.05%) at 1 h before esketamine and without oxymetazoline pretreatment. They were exposed to grass pollen in an allergen challenge chamber to induce allergic rhinitis symptoms at approximately 2 h before each esketamine administration until 1 h after. Healthy subjects self-administered esketamine (56 mg) before and after administration for 16 consecutive days of mometasone (200 µg), with the second esketamine dose administered 1 h after the last mometasone dose. The plasma pharmacokinetics of esketamine and noresketamine were assessed after each esketamine administration. The tolerability of esketamine, including effects on dissociative and potential psychotomimetic symptoms and level of sedation and suicidal ideation and behavior, was evaluated.

RESULTS

The rate of esketamine absorption was slightly greater in patients exhibiting symptoms of allergic rhinitis (decrease in median tmax from 32 min to 22 min). Increases in esketamine Cmax and AUC were also small (mean, ≤ 21%). The pharmacokinetics of esketamine was not affected by oxymetazoline or mometasone pretreatment. Esketamine was well tolerated when it was administered with or without pretreatment of oxymetazoline or mometasone.

CONCLUSIONS

Patients exhibiting symptoms of rhinitis may receive nasal esketamine spray without dose adjustment. In addition, esketamine may be administered 1 h after using a nasal decongestant or corticosteroid.

TRIAL REGISTRATION

The study was registered in the Clinical Trials (NCT02154334) and EudraCT (2014-000534-38) registries.

Birch-induced allergic rhinitis: Results of exposure during nasal allergen challenge, environmental chamber, and pollen season

Background

Pollen variation can affect field study data quality. Nasal allergen challenge (NAC) is considered the gold standard for evaluating allergic rhinitis, while environmental exposure chambers (EECs) are mainly used in phase 2 drug development studies. We aimed to study birch-induced allergic rhinitis under 3 different conditions.

Methods

This study included 30 participants allergic to birch pollen, based on birch skin prick test, specific immunoglobulin E (IgE), and positive NAC. Participants were exposed to placebo twice, followed by 2 consecutive 4-h birch airborne exposures, repeated on 2 occasions to evaluate reproducibility and priming effect. Nasal response was defined as total corrected nasal symptom score (ΔTNSS) ≥ 5 during NAC and EEC. The primary end-point was to measure TNSS during the last 2 h of first allergen exposure. TNSS was also analyzed during natural exposure.

Results

The dose most commonly yielding positive TNSS during NAC was 175.2 ng/200 μL. Eighteen participants experienced ΔTNSS ≥5 during the last 2 h of the first exposure, whereas 21 had positive responses at all 4 exposures. Mean ΔTNSS was 1 with placebo versus 6 with birch. Exposures were reproducible, with no observed priming effect. Airborne Bet v 1 was 25 ng/m³, while the pollen measurement was 279/m³ during pollen season. TNSS reached 5 in 67.9% of participants during peak pollen season.

Conclusion

EEC outcomes were similar to those obtained with NAC and natural exposure, suggesting the usefulness of EEC in allergic rhinitis studies. The primary end-point was reached, as 60% of participants experienced nasal responses.

Nasal residence time and rheological properties of a new bentonite-based thixotropic gel emulsion nasal spray - AM-301

OBJECTIVE

The present work provides characterization of rheological properties of a new bentonite-based thixotropic gel emulsion nasal spray (AM-301), its nasal residence time, distribution, safety and tolerability.

SIGNIFICANCE

The nasal epithelium is a portal of entry for allergens and primary infection by airborne pathogens. Non-pharmacological interventions, which enhance physical and biological barriers, protect against allergens and pathogens without drug-related side effects. AM-301 has shown promising efficacy and safety in the nasal epithelium against viruses (in vitro) and pollen (clinical).

METHODS

Technical part (i) spray characterization was performed with a validated droplet size distribution method; evaluation of the rheological properties of the formulation was performed by a validated amplitude sweep method and a validated oscillation, rotation, oscillation; Clinical part (ii) nasal and oropharyngeal endoscopy were used to provide a semi-quantitative evaluation of distribution and residence time of fluorescein-labelled AM-301 in the nose and oropharynx of healthy volunteers; (iii) tolerability and safety.

RESULTS

(i) The non-Newtonian rheological properties of the formulation allow AM-301 to be sprayed and then to revert to a gel to prevent run-off from the nasal cavity; (ii) the formulation remains on the inferior turbinate, septum and oropharynx of volunteers for up to 210 min and on the middle turbinate for up to 60 min; two nasal sprays provide no substantial benefit over a single application with regards to coverage or retention; (iii) the spray is well tolerated.

CONCLUSIONS

Single dose spray delivery of AM-301 provides extended coverage of the nasal mucosa up to the inferior turbinates.

Validated allergen exposure chamber is plausible tool for the assessment of house dust mite-triggered allergic rhinitis

BACKGROUND

Allergen exposure chamber (AEC) is a clinical facility that allows exposure to allergenic airborne particles in controlled environment. Although AECs offer stable levels of airborne allergens, the validation of symptoms and other endpoints induced by allergen challenge is key for their recommendation as a plausible tool for the assessment of patients, especially in clinical research. This study aimed to demonstrate the reproducibility of defined clinical endpoints after AEC house dust mite (HDM) challenge under optimal conditions in patients with allergic rhinitis (AR).

METHOD

HDM was distributed at different concentrations. The assessment was subjective by the patients: total nasal symptom score (TNSS), visual analog scale (VAS), and objective by the investigator: acoustic rhinometry, peak nasal inspiratory flow (PNIF), and nasal secretion weight. Safety was assessed clinically and by peak expiratory flow rate (PEFR) and forced expiratory volume in the first second (FEV₁ ).

RESULTS

Constant environment: temperature, humidity, and carbon dioxide (CO₂ ) concentration were maintained during all challenges. The concentration of HDM on average remained stable within the targeted values: 1000, 3000, 5000, 7000 particles (p)/m³ . Most symptoms were observed at concentrations 3000 p/m³ or higher. The symptoms severity and other endpoints results were reproducible. 5000 p/m³ , and challenge duration of 120 min were found optimal. The procedure was safe with no lung function abnormalities due to challenge.

CONCLUSION

HDM challenge in ALL-MED AEC offers a safe and reliable method for inducing symptoms in AR patients for the use in controlled clinical studies including allergen immunotherapy.

Large-scale provocation studies identify maladaptive responses to ubiquitous aeroallergens as a correlate of severe allergic rhinoconjunctivitis and asthma

BACKGROUND

Allergic asthma (AA) and allergic rhinoconjunctivitis (ARC) are common comorbid environmentally triggered diseases. We hypothesized that severe AA/ARC reflects a maladaptive or unrestrained response to ubiquitous aeroallergens.

METHODS

We performed provocation studies wherein six separate cohorts of persons (total n = 217) with ARC, with or without AA, were challenged once or more with fixed concentrations of seasonal or perennial aeroallergens in an aeroallergen challenge chamber (ACC).

RESULTS

Aeroallergen challenges elicited fully or partially restrained vs. unrestrained evoked symptom responsiveness, corresponding to the resilient and adaptive vs. maladaptive AA/ARC phenotypes, respectively. The maladaptive phenotype was evoked more commonly during challenge with a non-endemic versus endemic seasonal aeroallergen. In an AA cohort, symptom responses evoked after house dust mite (HDM) challenges vs. recorded in the natural environment were more accurate and precise predictors of asthma severity and control, lung function (FEV1), and mechanistic correlates of maladaptation. Correlates included elevated levels of peripheral blood CD4+ and CD8+ T-cells, eosinophils, and T-cell activation, as well as gene expression proxies for ineffectual epithelial injury/repair responses. Evoked symptom severity after HDM challenge appeared to be more closely related to levels of CD4+ and CD8+ T-cells than eosinophils, neutrophils, or HDM-specific IgE.

CONCLUSIONS

Provocation studies support the concept that resilience, adaptation, and maladaptation to environmental disease triggers calibrate AA/ARC severity. Despite the ubiquity of aeroallergens, in response to these disease triggers in controlled settings (ie, ACC), most atopic persons manifest the resilient or adaptive phenotype. Thus, ARC/AA disease progression may reflect the failure to preserve the resilient or adaptive phenotype. The triangulation of CD8+ T-cell activation, airway epithelial injury/repair processes and maladaptation in mediating AA disease severity needs more investigation.

Dosing intact birch pollen grains at the air-liquid interface (ALI) to the immortalized human bronchial epithelial cell line BEAS-2B

In real life, humans are exposed to whole pollen grains at the air epithelial barrier. We developed a system for in vitro dosing of whole pollen grains at the Air-Liquid Interface (ALI) and studied their effect on the immortalized human bronchial epithelial cell line BEAS-2B. Pollen are sticky and large particles. Dosing pollen needs resuspension of single particles rather than clusters, and subsequent transportation to the cells with little loss to the walls of the instrumentation i.e. in a straight line. To avoid high speed impacting insults to cells we chose sedimentation by gravity as a delivery step. Pollen was resuspended into single particles by pressured air. A pollen dispersion unit including PTFE coating of the walls and reduced air pressure limited impaction loss to the walls. The loss of pollen to the system was still about 40%. A linear dose effect curve resulted in 327-2834 pollen/cm2 (± 6.1%), the latter concentration being calculated as the amount deposited on epithelial cells on high pollen days. After whole pollen exposure, the largest differential gene expression at the transcriptomic level was late, about 7 hours after exposure. Inflammatory and response to stimulus related genes were up-regulated. We developed a whole pollen exposure air-liquid interface system (Pollen-ALI), in which cells can be gently and reliably dosed.

Cholinergic Synapse Pathway Gene Polymorphisms Associated With Late-Phase Responses in Allergic Rhinitis

Allergic rhinitis (AR) is characterized by an early-phase response (EPR), and in a subgroup of individuals, a late-phase response (LPR). We sought to investigate polymorphisms in cholinergic synapse pathway genes, previously associated with late-asthmatic responses, in the LPR. Twenty healthy participants and 74 participants with AR underwent allergen exposure using the Environmental Exposure Unit. Allergic participants were sub-phenotyped using self-reported nasal congestion scores; congestion is the predominant symptom experienced during the LPR. Acute congestion (AC, n = 36) participants developed only an EPR, while persistent congestion (PC, n = 38) participants developed both allergic responses. We interrogated blood samples collected before allergen exposure with genotyping and gene expression assays. Twenty-five SNPs located in ADCY3, AKT3, CACNA1S, CHRM3, CHRNB2, GNG4, and KCNQ4 had significantly different allele frequencies (P < 0.10) between PC and AC participants. PC participants had increased minor allele content (P = 0.009) in the 25 SNPs compared to AC participants. Two SNPs in AKT3 were associated with gene expression differences (FDR < 0.01) in PC participants. This study identified an association between the LPR and polymorphisms in the cholinergic synapse pathway genes, and developed a novel method to sub-phenotype AR using self-reported nasal congestion scores.

The use of nasal allergen vs allergen exposure chambers to evaluate allergen immunotherapy

INTRODUCTION

Allergen-specific immunotherapy (AIT) is the only disease-modifying treatment option for allergic rhinitis (AR) patients with persistent moderate-severe AR for whom traditional pharmacotherapies are ineffective. The nasal allergen challenge (NAC) and allergen exposure chamber (AEC) are two translational models of AR that can be used to investigate the properties, safety, and efficacy of AIT.

AREAS COVERED

Peer-reviewed, human-centered articles utilizing AEC or NAC models to investigate AIT between 2010 and 2020 were curated from PubMed, EMBASE, and OVID Medline databases. AECs have been used to evaluate traditional subcutaneous and sublingual administrations of AIT, including cross-protective effects and different dosing regimens. More recently, the effectiveness of novel AIT formulations has been evaluated. NACs are another model used to study AIT, including using novel intralymphatic routes of administration. It is an especially powerful and versatile tool to determine if basic science and animal model findings are clinically translatable.

EXPERT OPINION

The AEC and NAC models both produce clinically relevant and reproducible results. AECs are more effective for studying many participants but are limited because they require a specialized facility. As more AIT therapies and new formulations are developed over time, the versatility of the NAC will be especially useful.

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

Rationale

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

Methods

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

Results

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

Conclusions

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

The Effect of a Thixotropic Nasal Gel on Nasal Symptoms and Inflammatory Biomarkers in Seasonal Allergic Rhinitis

BACKGROUND

Drug-free viscous nasal applications have been shown to reduce nasal symptoms in individuals with seasonal allergic rhinitis (SAR). Nascum®-Plus (NP), a commercially available thixotropic gel, has been designed to reduce dryness and soreness of the nasal mucosa and prevent the absorption of small particles.

OBJECTIVES

The aim of this study was to assess the efficacy of single-dose NP in treating nasal symptoms and secretion during challenge in an allergen challenge chamber (ACC). Furthermore, the effect of this treatment on biomarkers and immune cells of the allergic cascade were measured.

METHODS

This open-label, cross-over, sequence-randomized, monocentric trial randomized 18 adults with SAR and a positive skin prick test reaction to Dactylis glomerata pollen to receive NP or no treatment during two 4-h ACC sessions 3 weeks apart. On Day 1, 9 subjects were challenged for 4 h with treatment, the other 9 without treatment, and vice versa on Day 22. Nasal lavage fluid and nasal filter eluate samples were obtained pre, 2, and 18 h post challenge in the ACC.

RESULTS

NP significantly reduced nasal symptoms, assessed by total nasal symptom score (p < 0.001), and minimized nasal secretion (p = 0.047), while no significant effect on biomarkers and immune cells in the nasal fluid was observed. The treatment was safe and well-tolerated.

CONCLUSIONS

The physical barrier built by NP nasal gel can be safely applied in patients with allergic rhinitis. It reduces allergic nasal symptoms and secretion, but application of a single dose does not affect local inflammatory biomarkers.

Recent developments and advances in atopic dermatitis and food allergy

This review highlights recent advances in atopic dermatitis (AD) and food allergy (FA), particularly on molecular mechanisms and disease endotypes, recent developments in global strategies for the management of patients, pipeline for future treatments, primary and secondary prevention and psychosocial aspects. During the recent years, there has been major advances in personalized/precision medicine linked to better understanding of disease pathophysiology and precision treatment options of AD. A greater understanding of the molecular and cellular mechanisms of AD through substantial progress in epidemiology, genetics, skin immunology and psychological aspects resulted in advancements in the precision management of AD. However, the implementation of precision medicine in the management of AD still requires the validation of reliable biomarkers, which will provide more tailored management, starting from prevention strategies towards targeted therapies for more severe diseases. Cutaneous exposure to food via defective barriers is an important route of sensitization to food allergens. Studies on the role of the skin barrier genes demonstrated their association with the development of IgE-mediated FA, and suggest novel prevention and treatment strategies for type 2 diseases in general because of their link to barrier defects not only in AD and FA, but also in asthma, chronic rhinosinusitis, allergic rhinitis and inflammatory bowel disease. The development of more accurate diagnostic tools, biomarkers for early prediction, and innovative solutions require a better understanding of molecular mechanisms and the pathophysiology of FA. Based on these developments, this review provides an overview of novel developments and advances in AD and FA, which are reported particularly during the last two years.

Clinical standardization of two controlled allergen challenge facilities: The Environmental Exposure Unit and the Biogenics Research Chamber

BACKGROUND

Controlled allergen challenge facilities (CACF), in disparate geographic regions with dissimilar engineering and base populations, have historically functioned as single, independent sites in clinical allergy trials. We aimed to demonstrate "between-unit reproducibility" to allow controlled challenge trials of participants using 2 CACFs.

OBJECTIVE

To compare and standardize 2 CACFs located in Kingston, Ontario, Canada, and San Antonio, Texas, by examining participant-reported symptom severity during qualifying and treatment visits and evaluating response to treatment, while using the same allergen.

METHODS

At 2 different CACFs, participants were enrolled in a double-blind, placebo-controlled, crossover intervention trial with cetirizine 10 mg. Different distribution devices delivered common short ragweed pollen via laminar air flow and maintained an airborne concentration of 3500 ± 700 grains/m³ in both facilities. A 1-hour "sham" run with no pollen release preceded a priming exposure of 3 hours and was followed 3 days later by a qualifying/treatment 5-hour exposure. At least 14 days later, another priming exposure was followed by the crossover exposure and treatment.

RESULTS

Forty-eight and 43 subjects completed the study at Kingston and San Antonio, respectively. Demographics were similar. Fewer than 10% exhibited symptoms with sham exposure. No significant differences were found between the 2 facilities in maximal total rhinoconjunctivitis symptom score, total nasal symptom score, and total ocular symptom score, nor in areas under the curve. In both facilities, no significant effects of cetirizine 10 mg over placebo were detected.

CONCLUSION

The results were equivalent, demonstrating that the 2 CACFs can be used together in dual-center clinical trials and show the possibility of multicenter trials involving multiple CACFs.

A birch sublingual allergy immunotherapy tablet reduces rhinoconjunctivitis symptoms when exposed to birch and oak and induces IgG4 to allergens from all trees in the birch homologous group

BACKGROUND

This randomized, double-blind trial was conducted to determine the optimal dose for clinical efficacy of the SQ tree SLIT-tablet. An environmental exposure chamber (EEC) was used to reduce variability of allergen exposure and allow investigation of symptom reduction towards different species from the birch homologous group in separate EEC sessions.

METHODS

Eligible subjects (N = 219) were randomized to receive treatment with placebo or the SQ tree SLIT-tablet (2, 7, or 12 DU) for 24 weeks. EEC pollen challenges were conducted outside the birch pollen season and included four birch and two oak EEC sessions. The primary efficacy endpoint was the average allergic rhinoconjunctivitis (ARC) total symptom score (TSS) after 24 weeks of treatment.

RESULTS

There was a statistically significantly lower TSS during the 24-week birch EEC session for 7 DU and 12 DU compared to placebo with relative differences of 24% (P = 0.03) and 25% (P = 0.02). For the 24-week oak EEC session, there was a statistically significant difference for 12 DU (24%, P = 0.03). IgE and IgG4 measurements supported these findings and demonstrated cross-reactivity to all other species within the birch homologous group. Treatment was well-tolerated with the most frequently reported adverse reactions being the local reactions in the oral cavity of mild-to-moderate severity.

CONCLUSION

This trial demonstrates that the SQ tree SLIT-tablet reduce ARC symptoms triggered by birch or oak pollen. The optimal dose for further development was 12 DU. Clinical and immunological findings suggest that the tablet may be used to treat allergies to all species within the birch homologous group.

Dynamic Changes in Heart Rate Variability and Nasal Airflow Resistance during Nasal Allergen Provocation Test

Allergic rhinitis is a major chronic respiratory disease and an immunoneuronal disorder. We aimed at providing further knowledge on the function of the neural system in nasal allergic reaction. Here, a method to assess simultaneously the nasal airflow resistance and the underlying function of autonomic nervous system (ANS) is presented and used during the nasal provocation of allergic and nonallergic subjects. Continuous nasal airflow resistance and spectral heart rate variability parameters show in detail the timing and intensity differences in subjects' reactions. After the provocation, the nasal airflow resistance of allergic subjects showed a positive trend, whereas LF/HF (Low Frequency/High Frequency) ratio and LF power showed a negative trend. This could imply a gradual sympathetic withdrawal in allergic subjects after the allergen provocation. The groups differed significantly by these physiological descriptors. The proposed method opens entirely new opportunities to research accurately concomitant changes in nasal breathing function and ANS.

EAACI Position paper on the standardization of nasal allergen challenges

Nasal allergen challenge (NAC) is an important tool to diagnose allergic rhinitis. In daily clinical routine, experimentally, or when measuring therapeutic success clinically, nasal allergen challenge is fundamental. It is further one of the key diagnostic tools when initiating specific allergen immunotherapy. So far, national recommendations offered guidance on its execution; however, international divergence left many questions unanswered. These differences in the literature caused EAACI to initiate a task force to answer unmet needs and find a consensus in executing nasal allergen challenge. On the basis of a systematic review containing nasal allergen challenges of the past years, task force members reviewed evidence, discussed open issues, and studied variations of several subjective and objective assessment parameters to propose a standardized way of a nasal allergen challenge procedure in clinical practice. Besides an update on indications, contraindications, and preparations for the test procedure, main recommendations are a bilaterally challenge with standardized allergens, with a spray device offering 0.1 mL per nostril. A systematic catalogue for positivity criteria is given for the variety of established subjective and objective assessment methods as well as a schedule for the challenge procedure. The task force recommends a unified protocol for NAC for daily clinical practice, aiming at eliminating the previous difficulty of comparing NAC results due to unmet needs.

[Environmental exposure chambers (EEC): A novel tool for pathophysiological and pharmaceutical research]

Airborne allergic diseases (allergic asthma, rhinitis and conjunctivitis) have reached epidemic proportions and are a great burden for both society and individuals. Therefore we need to better understand the physiopathological mechanisms and to increase clinical research in these diseases. However, traditional outpatient studies are difficult and have number of limitations, in particular the variability of allergen exposure. Yet allergen provocation tests, especially bronchial challenges in asthma, are excellent tools to measure the efficiency of anti-allergic therapies. Environmental exposure chambers (EEC) allow the performance of controlled allergen provocation tests on a large scale with remarkable sensitivity, specificity and reproducibility. Moreover, they allow a precise collection of allergic symptoms, making them interesting tools for patho-physiological and clinical studies. During the last thirty years, they have assisted the study of anti-allergic therapies and provided data on their pharmacodynamic characteristics, particularly in allergic rhinitis. However, there are still no EEC tests centered on asthma. The EEC of Strasbourg (ALYATEC^®) was developed to fulfill two objectives: to allow standardized allergenic and non-allergenic exposures with better control of the parameters than in other EEC and to offer a place to study asthma and anti-asthmatic therapies safely.

Nasal and ocular challenges

Nasal and ocular challenges facilitate the evaluation of subjective and objective responses to defined allergen or irritant exposure. Nasal and ocular allergen challenges are the gold standard to diagnose allergic rhinitis and conjunctivitis, respectively, and aid in the evaluation of novel therapies in clinical trials. Additionally, nasal and ocular allergen challenges might help identify medically relevant allergens in clinical practice. Nonspecific or irritant challenges evaluate mucosal hyperreactivity. Direct mucosal challenges, which can be performed in an office or research setting, expose the participant to higher allergen doses than common in the natural environment. Park studies and environmental chambers, which are most practical in clinical trials, more closely simulate natural allergen exposure. International consensus guidelines for nasal and ocular challenges do not exist. Therefore the positivity criteria, methodologies, and extract or allergen preparations used in challenges vary in the literature. Regardless of these limitations, nasal and ocular challenges are helpful clinical and research tools for nasal and ocular diseases.

International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis

BACKGROUND

Critical examination of the quality and validity of available allergic rhinitis (AR) literature is necessary to improve understanding and to appropriately translate this knowledge to clinical care of the AR patient. To evaluate the existing AR literature, international multidisciplinary experts with an interest in AR have produced the International Consensus statement on Allergy and Rhinology: Allergic Rhinitis (ICAR:AR).

METHODS

Using previously described methodology, specific topics were developed relating to AR. Each topic was assigned a literature review, evidence-based review (EBR), or evidence-based review with recommendations (EBRR) format as dictated by available evidence and purpose within the ICAR:AR document. Following iterative reviews of each topic, the ICAR:AR document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:AR document addresses over 100 individual topics related to AR, including diagnosis, pathophysiology, epidemiology, disease burden, risk factors for the development of AR, allergy testing modalities, treatment, and other conditions/comorbidities associated with AR.

CONCLUSION

This critical review of the AR literature has identified several strengths; providers can be confident that treatment decisions are supported by rigorous studies. However, there are also substantial gaps in the AR literature. These knowledge gaps should be viewed as opportunities for improvement, as often the things that we teach and the medicine that we practice are not based on the best quality evidence. This document aims to highlight the strengths and weaknesses of the AR literature to identify areas for future AR research and improved understanding.

Dose-response relationship of a new Timothy grass pollen allergoid in comparison with a 6-grass pollen allergoid

BACKGROUND

Subcutaneous allergen immunotherapy with grass pollen allergoids has been proven to be effective and safe in the treatment of patients with allergic rhinoconjunctivitis. Based on the extensive cross-reactivity among Pooideae species, it has been suggested that grass pollen extracts could be prepared from a single species, rather than from a multiple species mixture.

OBJECTIVE

To find the optimal dose of a Phleum pratense (P. pratense) allergoid preparation and compare its efficacy and safety to a 6-grass pollen allergoid preparation.

METHODS

In this double-blind, placebo-controlled study (EudraCT: 2011-000674-58), three doses of P. pratense allergoid (1800 therapeutic units (TU), standard-dose 6000 TU and 18 000 TU) were compared with placebo and the marketed 6-grass pollen allergoid (6000 TU). In a pre-seasonal dosing regimen, 102 patients were randomized to five treatment groups and received nine subcutaneous injections. The primary efficacy endpoint was the change in weal size (late-phase reaction [LPR]) in response to the intracutaneous testing (ICT) before and after treatment, comparing the active allergoids to placebo. Secondary outcomes were the change in Total Nasal Symptom Score (TNSS) assessed in the allergen exposure chamber (AEC), the changes in P. pratense-serum-specific IgG₄ and the incidence of adverse events (AEs).

RESULTS

All three doses of the P. pratense and the 6-grass pollen allergoid preparations were significantly superior to placebo for the primary outcome, whereas there were no significant differences in the change in TNSS. Compared to the standard-dose, the high-dose of P. pratense did not produce any additional significant benefit, but showed a slight increase in AEs. Yet this increase in AEs was lower than for the 6-grass pollen preparation.

CONCLUSIONS & CLINICAL RELEVANCE

The standard-dose of the new P. pratense allergoid was comparable to the marketed 6-grass pollen preparation at equal dose for the parameters measured.

Specificity and reproducibility of nasal biomarkers in patients with allergic rhinitis after allergen challenge chamber exposure

BACKGROUND

Allergic rhinitis is an inflammatory disease that causes cellular influx and mediator release in the nose. These inflammatory changes might be used as nasal biomarkers to assess the efficacy of novel anti-allergic treatments.

OBJECTIVE

To assess the specificity and reproducibility of nasal biomarkers in patients with allergic rhinitis after grass pollen exposure in an allergen challenge chamber.

METHODS

In a monocenter pilot study, 15 patients with allergic rhinitis and 19 healthy individuals underwent two 4-hour Dactylis glomerate pollen challenges in the challenge chamber with an interval of 21 days. Before challenge, on exit, and after 2 and 22 hours, a nasal lavage was performed and nasal secretions were collected on filter paper to determine a wide panel of cells and mediators. Furthermore, total nasal symptom score, nasal flow, and nasal nitric oxide were measured.

RESULTS

Pollen exposure significantly increased eosinophil, interleukin (IL) 5, IL-6, IL-13, and macrophage inflammatory protein 1β levels in allergic patients but not in healthy individuals. The effect could be reproduced for eosinophils, IL-5, IL-6, and macrophage inflammatory protein 1β after the second allergen challenge. By contrast, the IL-13 levels were higher and eotaxin levels first increased after repetitive allergen challenge. There was no correlation between total nasal symptom score and elevated cell or cytokine levels. Nasal nitric oxide levels were nonspecifically elevated in both patients with allergy and healthy controls.

CONCLUSION

A subset of cellular and soluble biomarkers in nasal lavage and secretion reveals specificity and reproducibility in patients with allergic rhinitis. These can be used to measure the immunologic efficacy of antiallergic treatments in an allergen challenge chamber. Carryover effects attributable to priming must be considered when designing cross-over studies.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00297843.

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.

Specificity and sensitivity assessment of selected nasal provocation testing techniques

Introduction

Nasal provocation testing involves an allergen-specific local reaction of the nasal mucosa to the administered allergen.

Aim

To determine the most objective nasal occlusion assessment technique that could be used in nasal provocation testing.

Material and methods

A total of 60 subjects, including 30 patients diagnosed with allergy to common environmental allergens and 30 healthy subjects were enrolled into the study. The method used in the study was a nasal provocation test with an allergen, with a standard dose of a control solution and an allergen (5,000 SBU/ml) administered using a calibrated atomizer into both nostrils at room temperature. Early-phase nasal mucosa response in the early phase of the allergic reaction was assessed via acoustic rhinometry, optical rhinometry, nitric oxide in nasal air, and tryptase levels in the nasal lavage fluid.

Results

In estimating the homogeneity of the average values, the Levene’s test was used and receiver operating characteristic curves were plotted for all the methods used for assessing the nasal provocation test with an allergen. Statistically significant results were defined for p < 0.05. Of all the objective assessment techniques, the most sensitive and characteristic ones were the optical rhinometry techniques (specificity = 1, sensitivity = 1, AUC = 1, PPV = 1, NPV = 1).

Conclusions

The techniques used showed significant differences between the group of patients with allergic rhinitis and the control group. Of all the objective assessment techniques, those most sensitive and characteristic were the optical rhinometry.

Safety, efficacy and repeatability of a novel house dust mite allergen challenge technique in the Fraunhofer allergen challenge chamber

BACKGROUND

Efficacy testing of immunotherapy in field studies is often hampered by variation of airborne allergens. Standardized allergen exposure in challenge chamber settings might be an alternative. Therefore, we developed a universal technique to create an atmosphere loaded with allergen particles of adjustable size from aqueous solutions of licensed allergen extracts.

OBJECTIVE

The aim of this study was to apply this technique and test the safety and efficacy of challenges with house dust mite (HDM) allergen in the Fraunhofer allergen challenge chamber.

METHODS

Aerosol particles carrying HDM allergen were produced by spray-drying of an aqueous solution containing HDM allergen and lactose. In a monocenter, placebo-controlled, single-blind, dose-escalation pilot study, 18 subjects with perennial allergic rhinitis and sensitization to HDM were exposed to HDM allergen for 4 h at either 250, 500, 1000 SQE/m³ or lactose alone (0 SQE/m³ ) 7 days apart. The dose of 500 SQE/m³ was repeated to investigate reproducibility. Total nasal symptom score (TNSS) was the primary endpoint.

RESULTS

Exposure to HDM increased TNSS (mean ± SD) to 3.4 ± 1.8, 3.3 ± 2.1, and 3.6 ± 2.0 at 250, 500 and 1000 SQE/m³ , respectively, while lactose alone did not change TNSS (0.7 ± 0.6). The results were reproducible at 500 SQE/m³ . Pulmonary function and adverse event frequency did not change with escalation of allergen dose.

CONCLUSION

This HDM allergen particle generation is safe, specific and reproducible and can therefore be used for efficacy testing of immunotherapy and for basic clinical research.

Clinical validation of controlled exposure to birch pollen in the Environmental Exposure Unit (EEU)

BACKGROUND

The Environmental Exposure Unit (EEU) in Kingston, Ontario, Canada is a controlled allergen challenge facility (CACF) that has been previously clinically validated for the use of ragweed and grass pollen in clinical studies. In this study we aim to validate the use of birch pollen to challenge allergic participants.

METHODS

A total of 59 volunteers were screened and 38 birch allergic participants and ten non-allergics completed the study, outside of tree pollen season. Participants had to have a minimum of 2-year history of allergic rhinoconjunctivitis during the typical tree pollen season and have a positive skin prick test to birch allergen ≥5 mm from the control. Qualified participants were exposed to birch (Betula pendula) pollen for 4 h in the EEU and recorded their symptoms of sneezing, rhinorrhea, nasal congestion, nasal itch which comprised the total nasal symptom score (TNSS), as well as itchy/watery eyes, red/burning eyes and itching of ears/palate/throat which along with the TNSS comprised the total rhinoconjunctival symptom score (TRSS) along with Peak Nasal Inspiratory Flow (PNIF) at baseline and at 30 min intervals for the duration of exposure, then hourly for up to 12 h from the start of exposure.

RESULTS

Allergic participants reported a gradual rise in TNSS and TRSS, reaching a mean and standard error of the mean of 7.08 ± 0.45 and 11.58 ± 0.93 respectively by 180 min from the start of exposure. Symptoms gradually declined to near baseline values following departing from the unit, reaching 1.9 and 2.7 by 450 min. Allergic participants reported significantly higher TNSS than non-allergics starting from 30 min (p < 0.01, two-way ANOVA with Bonferroni corrections), maintaining maximum significance from 60 to 300 min (p < 0.0001) and losing significance by 420 min. TRSS and PNIF followed similar trends as those seen with TNSS. Participants were phenotyped using previously published definitions using the TNSS into Early Phase Responders (EPR, 57.8 %), protracted EPR (pEPR, 39.5 %), and Dual Phase Responders (DPR, 2.7 %).

CONCLUSIONS

The EEU can competently challenge birch allergic participants and achieve statistically significant changes in symptoms and nasal airflow, while such changes are not reported in non-allergic controls. Trial registration NCT02351830 clinicaltrials.gov.

Validation of the Global Allergy and Asthma European Network (GA2LEN) chamber for trials in allergy: Innovation of a mobile allergen exposure chamber

BACKGROUND

Field clinical trials of pollen allergy are affected by the impossibility of predicting and determining individual allergen exposure because of many factors (eg, pollen season, atmospheric variations, pollutants, and lifestyles). Environmental exposure chambers, delivering a fixed amount of allergen in a controlled environmental setting, can overcome these limitations. Environmental exposure chambers are currently already used in phase 2, 3, and even 4 trials. Unfortunately, few chambers exist in the world, and this makes it difficult to perform large, multicenter clinical trials. The new Global Allergy and Asthma European Network (GA²LEN) mobile exposure chamber is a step forward because the mobility of the chamber makes it convenient for patients to participate in clinical testing.

OBJECTIVE

This study was made to validate the reproducibility, sensitivity, and specificity of the results obtained in the new GA²LEN chamber.

METHODS

Seventy-two adult patients (19-61 years old) with allergic rhinitis with or without asthma caused by grass pollen were included in different clinical validation tests. Total symptom scores and total nasal symptom scores were recorded at time zero (0) and every 10 minutes during exposures, along with nasal and respiratory parameters.

RESULTS

Exposure tests confirmed the reproducibility between subsequent runs and the sensitivity (P < .00001 vs patients exposed to placebo) and specificity (very low score in nonallergic subjects) in the GA²LEN chamber. No adverse reactions were recorded during the tests.

CONCLUSIONS

The mobility of the GA²LEN chamber provides a new, potentially effective, and safe way of generating reliable data in allergy multicenter clinical trials.

Method for a homogeneous distribution of pollens in an environmental exposure chamber

BACKGROUND

A variety of different environmental exposure chambers (EECs) have been used to evaluate treatments for allergic rhinitis.

OBJECTIVE

To describe and test a system for a homogenous distribution of grass pollen, Phleum Pratense, in an EEC to be used for controlled pollen exposure studies in allergic participants.

METHODS

A chamber made of stainless steel with completely rounded corners, seating four individuals at a time, was used. Room pressure, temperature, humidity and the air change rate were kept constant throughout the study period. A rotating pipette dispensed a uniform supply of pollen into a turntable's v-shaped grooves. A stainless steel capillary tube sucked the pollens into a venturi throat at which time the pollens were mixed with a high-pressure airstream of compressed high-efficiency particulate arrestance filtered air and then transported to a spreading plate inside the EEC. To achieve uniform concentrations in the EEC, the turntable's rotating speed was continuously adjusted using information from video-coupled feedback and feed forward mechanisms. Pollen levels were detected using standard volumetric air samplers and laser particle counters. The target pollen exposure level was 1000 pollens/m(3) . Twenty-one participants were exposed to pollens in the EEC twice for 210 min. Participants evaluated their symptoms every 30 min using a total nasal symptom score (TNSS) consisting of blocked nose, runny nose, nasal itching and sneezing.

RESULTS

Across fifteen study days, the average pollen level was 982 pollens/m(3) (SD, 102 pollens/m(3) ). On average, participants experienced a 10% difference in overall pollen levels between their two visits to the EEC. The mean TNSSs rose throughout the exposure period, with a low at baseline of 0.43 (SD, 0.68) to a high of 4.71 (SD, 2.43) just before exiting the EEC.

CONCLUSION AND CLINICAL RELEVANCE

This EEC provides a reproducible, precise and homogenous distribution of pollens making it suitable for single-centre allergy clinical trials.

Efficacy of endonasal phototherapy for relieving the symptoms of allergic rhinitis: Meta-analysis

BACKGROUND

Endonasal phototherapy can relieve the symptoms of allergic rhinitis (AR) for the patient. However, there is no consensus on whether or not endonasal phototherapy is effective in reducing the symptoms of AR.

OBJECTIVE

The goal of this meta-analysis was to perform a systematic review of the available literature on the effects of endonasal phototherapy on symptoms of AR.

METHODS

Two authors independently searched medical literature databases from their inception of article collection to July 2014. Studies that scored the nasal symptoms of AR and quality of life related to AR before and after endonasal phototherapy, and that compared the effects of phototherapy (treatment groups) with sham treatment (sham group) or antihistamine administration (antihistamine group) were included in the analysis. The outcomes of interest were total nasal symptom scores, disease-specific quality of life questionnaire assessments, and endoscopic findings (discharge and turbinate hypertrophy). Overall, a total of 13 trials met the inclusion criteria of this study, with a total sample size of 679 patients.

RESULTS

Phototherapy significantly reduced nasal symptoms compared with pretreatment values and improved quality of life. The endoscopic findings also significantly improved after phototherapy. In addition, the symptom score and disease-specific quality of life after treatment were significantly lower in the treatment group versus the sham group, and were similar to those in the antihistamine group.

CONCLUSIONS

Phototherapy could provide nasal symptom relief and improve quality of life related to AR. However, when considering the insufficient evaluation of the efficacy of phototherapy according to the treatment methods and the high heterogeneity apparent in some parameters, further clinical trials with robust research methodologies should be conducted to confirm the results of this study.

Controlled Allergen Challenge Facilities and Their Unique Contributions to Allergic Rhinitis Research

The aim of this study is to review advances in basic and clinical allergic rhinitis (AR) research over the past decade that have been conducted using controlled allergen challenge facility (CACF) models of allergen challenge. Databases, including PubMed, Medline, and Web of Science were searched for articles employing an ambient pollen exposure in a controlled facility to study AR, published between 2004 and the present date, using the terms as follows: CACF, Environmental Exposure Unit (EEU), Vienna Challenge Chamber (VCC), Fraunhofer Institute Environmental Challenge Chamber, Atlanta Allergen Exposure Unit, Biogenics Research Chamber, Allergen BioCube, Chiba and Osaka Environmental Challenge Chamber, exposure unit, challenge chamber, or environmental exposure chamber. Articles were then selected for relevance to the goals of the present review, including important contributions toward clinical and/or basic science allergy research. CACFs offer sensitive, specific, and reproducible methodology for allergen challenge. They have been employed since the 1980s and offer distinct advantages over traditional in-season multicentre trials when evaluating new treatments for AR. They have provided clinically applicable efficacy and pharmacologic information about important allergy medications, including antihistamines, decongestants, antileukotrienes, immunotherapies, and nasal steroids. CACF models have also contributed to basic science and novel/experimental therapy research. To date, no direct studies have been conducted comparing outcomes from one CACF to another. Over the past decade, CACF models have played an essential role in investigating the pathophysiology of AR and evaluating new therapies. The future opportunities for this model continue to expand.

Efficacy and safety of a novel nasal steroid, S0597, in patients with seasonal allergic rhinitis

BACKGROUND

Allergic rhinitis (AR) poses a significant global burden with increasing prevalence. Although intranasal glucocorticosteroids are effective, older agents can have limiting side effects. S0597, a novel intranasal glucocorticosteroid, has demonstrated good safety and tolerability during preclinical and phase 1 studies.

OBJECTIVE

To assess the clinical efficacy, safety, and tolerability of different doses of S0597 nasal spray vs placebo in patients with seasonal AR.

METHODS

This phase 2, randomized, double-blinded, placebo-controlled, parallel-group, single-center study randomized 159 patients 18 to 65 years old (mean age 37.8 years) with a positive skin prick test reaction for Dactylis glomerata to receive S0597 at 200, 400, or 800 μg/d or placebo for 15 days. On days 1 (baseline), 15, and 16, patients underwent a 4-hour pollen challenge to evaluate treatment efficacy measured by the change in total nasal symptom score (TNSS) from baseline to days 15 and 16 and changes in TNSS subscales and nasal secretion.

RESULTS

Statistically significant improvements in TNSS from baseline to days 15 and 16 were observed with all S0597 doses vs placebo (P = .0005 overall), with the greatest improvements observed in the highest-dose group (P < .0001). Significant decreases were observed in each S0597 dose group vs placebo for TNSS subscales and nasal secretion. Improvements in nasal secretion were related to dose, with the greatest decreases from baseline in the 800-μg/d group on days 15 and 16 (P < .0001).

CONCLUSION

Treatment with S0597 at 200, 400, and 800 μg/d by 2 divided doses for 2 weeks was safe and significantly more effective than placebo for improving nasal symptoms associated with grass pollen-induced seasonal AR in adults.

TRIAL REGISTRATION

ClinicalTrials.gov, identifier NCT01614691.

Exacerbation of atopic dermatitis on grass pollen exposure in an environmental challenge chamber

BACKGROUND

It has frequently been speculated that pruritus and skin lesions develop after topical exposure to aeroallergens in sensitized patients with atopic dermatitis (AD).

OBJECTIVE

We sought to study cutaneous reactions to grass pollen in adult patients with AD with accompanying clear IgE sensitization to grass allergen in an environmental challenge chamber using a monocenter, double-blind, placebo-controlled study design.

METHODS

Subjects were challenged on 2 consecutive days with either 4000 pollen grains/m(3) of Dactylis glomerata pollen or clean air. The severity of AD was assessed at each study visit up to 5 days after challenge by (objective) scoring of AD (SCORAD). Additionally, air-exposed and non-air-exposed skin areas were each scored using local SCORAD scoring and investigator global assessments. Levels of a series of serum cytokines and chemokines were determined by using a Luminex-based immunoassay. The primary end point of the study was the change in objective SCORAD scores between prechallenge and postchallenge values.

RESULTS

Exposure to grass pollen induced a significant worsening of AD. A pronounced eczema flare-up of air-exposed rather than covered skin areas occurred. In grass pollen-exposed subjects a significantly higher increase in CCL17, CCL22, and IL-4 serum levels was observed.

CONCLUSIONS

This study demonstrates that controlled exposure to airborne allergens of patients with a so-called extrinsic IgE-mediated form of AD induced a worsening of cutaneous symptoms.

In vivo diagnosis of allergic diseases--allergen provocation tests

The allergen challenge test has been the mainstay of diagnosis of allergic diseases for a long time since it offers a direct proof of the clinical relevance of a particular allergen for the allergic disease symptoms and severity. Standardisation and availability for daily practice (including safety issues) are still to be refined but most of the challenge tests have safely crossed the border from research tools to diagnostic tests available for daily practice for a well trained clinical staff.

Environmental exposure chambers in allergen immunotherapy trials: Current status and clinical validation needs

As required by the European Medicines Agency and the US Food and Drug Administration for pivotal trials involving allergen immunotherapy (AIT) products, clinical efficacy assessment is currently based on double-blind, placebo-controlled field studies with natural allergen exposure during the allergen season. However, this study design is associated with several drawbacks, such as the high variability of allergen exposure in different trial sites or seasons and the presence of confounding environmental factors. On the contrary, environmental exposure chambers (EECs) aim to operate with a stable and reproducible allergen exposure under highly standardized environmental conditions. Technical validation parameters for different EECs worldwide have been published by several groups. However, full clinical validation of EEC study outcomes is required for their classification as an appropriate alternative to natural allergen exposure for AIT product efficacy assessment. Some clinical validation parameters have already been addressed for EEC units. The reliability of provoked symptoms in repeated EEC sessions is high, but the predictive power of EEC settings for the clinical response on natural exposure and the impact of seasonal priming on test results still have to be validated systematically, as does the inter-EEC variability. Thus the authors recommend a continued in-depth validation of EECs to exploit the potential of this technology for future AIT product development.

Recommendations for the standardization of clinical outcomes used in allergen immunotherapy trials for allergic rhinoconjunctivitis: an EAACI Position Paper

BACKGROUND

Allergen immunotherapy (AIT) has been thoroughly documented in randomized controlled trials (RCTs). It is the only immune-modifying and causal treatment available for patients suffering from IgE-mediated diseases such as allergic rhinoconjunctivitis, allergic asthma and insect sting allergy. However, there is a high degree of clinical and methodological heterogeneity among the endpoints in clinical studies on AIT, for both subcutaneous and sublingual immunotherapy (SCIT and SLIT). At present, there are no commonly accepted standards for defining the optimal outcome parameters to be used for both primary and secondary endpoints.

METHODS

As elaborated by a Task Force (TF) of the European Academy of Allergy and Clinical Immunology (EAACI) Immunotherapy Interest Group, this Position Paper evaluates the currently used outcome parameters in different RCTs and also aims to provide recommendations for the optimal endpoints in future AIT trials for allergic rhinoconjunctivitis.

RESULTS

Based on a thorough literature review, the TF members have outlined recommendations for nine domains of clinical outcome measures. As the primary outcome, the TF recommends a homogeneous combined symptom and medication score (CSMS) as a simple and standardized method that balances both symptoms and the need for antiallergic medication in an equally weighted manner. All outcomes, grouped into nine domains, are reviewed.

CONCLUSION

A standardized and globally harmonized method for analysing the clinical efficacy of AIT products in RCTs is required. The EAACI TF highlights the CSMS as the primary endpoint for future RCTs in AIT for allergic rhinoconjunctivitis.

Sublingual immunotherapy: World Allergy Organization position paper 2013 update

We have prepared this document, "Sublingual Immunotherapy: World Allergy Organization Position Paper 2013 Update", according to the evidence-based criteria, revising and updating chapters of the originally published paper, "Sublingual Immunotherapy: World Allergy Organization Position Paper 2009", available at http://www.waojournal.org. Namely, these comprise: "Mechanisms of sublingual immunotherapy;" "Clinical efficacy of sublingual immunotherapy" - reporting all the data of all controlled trials published after 2009; "Safety of sublingual immunotherapy" - with the recently published Grading System for adverse reactions; "Impact of sublingual immunotherapy on the natural history of respiratory allergy" - with the relevant evidences published since 2009; "Efficacy of SLIT in children" - with detailed analysis of all the studies; "Definition of SLIT patient selection" - reporting the criteria for eligibility to sublingual immunotherapy; "The future of immunotherapy in the community care setting"; "Methodology of clinical trials according to the current scientific and regulatory standards"; and "Guideline development: from evidence-based medicine to patients' views" - including the evolution of the methods to make clinical recommendations.Additionally, we have added new chapters to cover a few emerging crucial topics: "Practical aspects of schedules and dosages and counseling for adherence" - which is crucial in clinical practice for all treatments; "Perspectives and new approaches" - including recombinant allergens, adjuvants, modified allergens, and the concept of validity of the single products. Furthermore, "Raising public awareness about sublingual immunotherapy", as a need for our patients, and strategies to increase awareness of allergen immunotherapy (AIT) among patients, the medical community, all healthcare stakeholders, and public opinion, are also reported in detail.

Characteristics of the Chiba environmental challenge chamber

BACKGROUND

An environmental challenge chamber (ECC), which we refer to as the α-chamber, was built at Chiba University in 2008. The aim of this study was to validate the functionality of the ECC.

METHODS

The stability of the pollen distribution and concentration in the ECC and symptoms of patients with Japanese cedar pollinosis induced by cedar pollen exposure were examined. Carryover effects of symptoms induced by different exposure protocols and correlations between symptoms induced in the ECC and those in the natural cedar pollen season were also determined. All the studies using the α-chamber were conducted out of the cedar pollen season.

RESULTS

The severity of symptoms in the chamber reached a peak about 2 hours after the start of pollen exposure and plateaued thereafter. After subjects left the chamber, the symptoms persisted for several days. There was no significant difference between the severity of symptoms at exposure levels of 8000 and 12000 grains/m3. The symptoms were significantly increased by exposure for 3 consecutive days; however, there were no carryover effects in a study performed with a two-week interval. The total nasal symptom score (TNSS) in the natural pollen season showed a weak correlation with the mean TNSS on the day of exposure and the following 3 days. Symptoms in the ECC also had weak correlations with those in the early natural pollen season.

CONCLUSIONS

The ECC under well-controlled conditions is suitable for clinical studies and might accelerate development of treatment for seasonal allergic rhinitis. A complete evaluation requires inclusion of the persistent reaction after subjects leave the ECC.

Double-blind, placebo-controlled, dose-ranging study of new recombinant hypoallergenic Bet v 1 in an environmental exposure chamber

BACKGROUND

Recombinant allergens offer a tool for improving specific immunotherapy (SIT).

OBJECTIVE

To find the optimal dose of a new hypoallergenic folding variant of recombinant Bet v 1 (rBet v 1-FV) as SIT for patients with birch pollen allergy.

METHODS

Before SIT, thirty-seven adult patients were exposed for eight hours in an environmental exposure chamber (EEC) to birch pollen at an average concentration of 3500 ± 500 grains/m(3) , then randomized to four maintenance dose groups of rBet v 1-FV and one placebo group: 20 μg (n = 7), 80 μg (n = 8), 160 μg (n = 7), 320 μg (n = 8), and placebo (n = 7). Patients were treated for 10 weeks with weekly injections and then re-exposed in the EEC. The optimal dose for SIT was assessed using efficacy results from the EEC, IgG responses, and tolerability.

RESULTS

Thirty-six patients were evaluable for efficacy assessment. The total symptom score significantly decreased in all active groups compared with placebo (-18.8% for placebo patients; -71.9%, P = 0.0022 for 20 μg; -75.6%, P = 0.0007 for 80 μg; -81.8%, P = 0.0009 for 160 μg; -78.3%, P = 0.0003 for 320 μg). IgG1 increased significantly in all active groups compared to placebo. All four active doses were well tolerated, no serious adverse event occurred; two Grade II reactions, according to EAACI classification, were observed, one in each of the 160- and 320-μg groups.

CONCLUSIONS

Considering efficacy, immunological response, and tolerability, a maintenance dose of 80 μg of rBet v 1-FV appears to be the ideal dose for allergen immunotherapy in birch pollen allergic patients.

Developments in the field of allergy in 2010 through the eyes of Clinical and Experimental Allergy

In 2010 over 200 articles were published in Clinical and Experimental Allergy including editorials, reviews, opinion articles, letters, book reviews and of course at the heart of the journal, papers containing original data which have moved the field of allergy forward on a number of fronts. For the third year running the editors felt it would be of value to summarize the key messages contained in these papers as a snapshot of where the cutting edge of research into allergic disease is leading. We have broadly followed the sections of the journal, although this year the mechanistic articles are grouped together and the studies involving experimental models of disease are discussed throughout the paper. In the field of asthma and rhinitis phenotypes and biomarkers continue to a major pre-occupation of our authors. There is continued interest in mechanisms of inflammation and disordered lung function with the mouse model of asthma continuing to offer new insights. There is also a steady flow of papers investigating new therapies, including those derived from plants and herbs, although many are mechanistic with too few high quality clinical trials. The mechanisms involved in allergic disease are well covered with many strong papers using clinical material to ask relevant questions. Pro-pre and snybiotics continue to be of major interest to our authors and this remains a controversial and complicated field. The discipline of epidemiology has retained its interest in risk factors for the development of allergic disease with a view to refining and debating the reasons for the allergy epidemic. There is continued interest in the relationship between helminthic disease and allergy with a new twist in 2010 involving studies using infection with helminths as a potential treatment. The genetics of allergic disease continues to be very productive, although the field has moved on from only investigating single nucleotide polymorphisms of candidate genes to Genome Wide Association Studies and an increasing and welcome emphasis on gene-environment interactions. In the field of clinical allergy there is steady flow of papers describing patterns of drug allergy with renewed interest in reactions to contrast media, but food allergy is the major area of interest in this section of the journal. Lastly in the field of allergens there is a growing interest in the role of component resolved diagnosis in improving the diagnosis and management of allergic disease. Another excellent year, full of fascinating and high quality work, which the journal has been proud to bring to the allergy community.

Responses to ragweed pollen in a pollen challenge chamber versus seasonal exposure identify allergic rhinoconjunctivitis endotypes

BACKGROUND

The level of concordance between allergic symptoms induced on exposure to pollen in a pollen challenge chamber (PCC) versus the natural season is unknown.

OBJECTIVE

We sought to test the hypothesis that the symptom levels of allergic rhinoconjunctivitis elicited after out-of-season exposure to short ragweed in a PCC and during the natural season for giant ragweed pollen are highly correlated.

METHODS

Thirty-one ragweed-sensitive participants recorded symptoms for 15 days during the natural giant ragweed season in San Antonio, Texas. Twenty-six of these participants were challenged to short ragweed pollen in a PCC for 3 hours per day for up to 4 days.

RESULTS

In the PCC participants were dichotomized into those in whom low versus high levels of symptoms developed slowly or rapidly (ie, slow/low vs rapid/high). Each successive exposure visit associated with a progressive increase in symptom levels that approximated those experienced during the natural season. Hierarchic clustering identified 3 endotypes: endotypes I and II reflected concordantly low (n= 7) versus high (n = 14) total symptom scores (TSSs) in both the natural season and the PCC, respectively. Accordingly, the correlation between the TSSs recorded in the natural season and in the PCC for these 21 participants was very high. Although participants with endotype III (n = 5) had greater TSSs in the natural season than in the PCC, the degree of correlation between the TSSs remained high.

CONCLUSIONS

Our findings affirm our hypothesis, underscore the high cross-reactivity between distinct pollens, and highlight the utility of the PCC to identify novel allergy endotypes that might have contrasting mechanistic underpinnings and potentially therapeutic responses.

Domestic airborne black carbon and exhaled nitric oxide in children in NYC

Differential exposure to combustion by-products and allergens may partially explain the marked disparity in asthma prevalence (3-18%) among New York City neighborhoods. Subclinical changes in airway inflammation can be measured by fractional exhaled nitric oxide (FeNO). FeNO could be used to test independent effects of these environmental exposures on airway inflammation. Seven- and eight-year-old children from neighborhoods with lower (range 3-9%, n=119) and higher (range 11-18%, n=121) asthma prevalence participated in an asthma case-control study. During home visits, FeNO was measured, and samples of bed dust (allergens) and air (black carbon; BC) were collected. Neighborhood built-environment characteristics were assessed for the 500 m surrounding participants' homes. Airborne BC concentrations in homes correlated with neighborhood asthma prevalence (P<0.001) and neighborhood densities of truck routes (P<0.001) and buildings burning residual oil (P<0.001). FeNO concentrations were higher among asthmatics with than in those without frequent wheeze (≥4 times/year) (P=0.002). FeNO concentrations correlated with domestic BC among children without seroatopy (P=0.012) and with dust mite allergen among children with seroatopy (P=0.020). The association between airborne BC in homes and both neighborhood asthma prevalence and FeNO suggest that further public health interventions on truck emissions standards and residual oil use are warranted.