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.

Birch-naive, oak-allergic subjects' response to birch pollen in an environmental chamber

Background: Oak and birch pollens are strongly cross-reactive. It is unknown how robust this cross-reactivity is in patients without natural exposure to pollen of both trees. We assessed the symptom response to birch pollen in subjects with skin-prick test (SPT) results positive to oak and birch but only naturally exposed to oak by using an allergen challenge chamber. Methods: The subjects with SPT results positive to oak and birch had their serum-specific immunoglobulin E (ssIgE) to oak and birch antigens measured. Residential historical data were obtained. The subjects were exposed to birch pollen (3500 ± 700 grains/m³) in two consecutive 3-hour challenges. Symptoms were recorded at baseline and 30-minute intervals. Results: Twenty-four subjects, 12 men; ages 20-58 years, completed the study. Sixteen subjects (66.7%) responded with high Total Symptom Scores (TSS) ≥10 of a maximum 21. Twelve subjects (50%) had ssIgE values ≥0.70 kU/L to oak, 10 of whom had ssIgE values ≥0.70 kU/L to birch. These 10 subjects had a significantly higher maximum TSS than the rest. Also, 15 subjects without a previous natural exposure to birch pollen responded with TSS equivalent to the 9 subjects with previous exposure. Conclusion: Virginia live oak ssIgE levels of patients allergic to oak and birch correlated with the symptom response to birch pollen exposure, even without previous natural exposure to birch. The subjects naive to birch pollen responded to birch pollen exposure with symptoms comparable with both those with previous sustained exposure and also those who resided in endemic areas, as reported by other researchers.

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.

Olopatadine-mometasone combination nasal spray: Evaluation of efficacy and safety in patients with seasonal allergic rhinitis

Background: GSP301 is an investigational fixed-dose combination nasal spray that contains the antihistamine, olopatadine hydrochloride (HCl), and the corticosteroid, mometasone furoate. Objective: To evaluate the efficacy and safety of GSP301 in patients with seasonal allergic rhinitis (SAR). Methods: In this double-blind, randomized, parallel-group study, patients (≥12 years of age) with SAR were equally randomized to intranasal GSP301 (olopatadine 665 μg and mometasone 25 μg), olopatadine HCl (665 μg), mometasone furoate (25 μg), or placebo for 14 days of twice-daily treatment. The primary end point was the mean change from baseline in the average A.M. and P.M. 12-hour reflective Total Nasal Symptom Score (rTNSS) analyzed by using mixed-effect model repeated measures (p < 0.05 indicates statistical significance). Additional assessments included instantaneous TNSS (iTNSS), individual nasal symptoms, reflective Total Ocular Symptom Score (rTOSS) and instantaneous Total Ocular Symptom Score (iTOSS), onset of action, Physician-assessed Nasal Symptom Score (PNSS), quality of life, and adverse events (AE). Results: A total of 1180 patients were randomized. Over 14 days of treatment, GSP301 significantly improved average A.M. and P.M. rTNSS versus placebo (least squares mean difference -0.98 [95% confidence interval, -1.38 to -0.57]; p < 0.001) and versus olopatadine (p = 0.003), and approached statistical significance versus mometasone (p = 0.059). GSP301 also significantly improved average A.M. and P.M. iTNSS versus placebo and both monotherapies (p < 0.05, all). Further, GSP301 significantly improved individual nasal symptoms, overall ocular symptoms (rTOSS and iTOSS), and overall quality of life versus placebo (p < 0.01, all). Onset of action for GSP301 was observed within 15 minutes and was maintained at all subsequent time points assessed. Results for the PNSS also were significant for GSP301 versus placebo (p < 0.001). The percentages of patients with treatment-emergent AEs treated with GSP301, olopatadine, mometasone, and placebo were 12.9, 12.5, 7.1, and 9.4%, respectively. Conclusion: GSP301 was efficacious and well tolerated for the treatment of SAR symptoms compared with placebo, with a rapid onset of action of 15 minutes in patients ≥12 years of age.Clinical trial NCT02631551, <ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.clinicaltrials.gov">www.clinicaltrials.gov</ext-link>.

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.

Redness response phenotypes of allergic conjunctivitis in an allergen challenge chamber

BACKGROUND

There are few direct data concerning symptom dynamics of allergic conjunctivitis (AC) in an allergen challenge chamber (ACC).

OBJECTIVE

To determine the AC dynamics on subsequent exposures to ragweed pollen (RW) in individuals with allergic rhinitis in an ACC. To determine whether consecutive exposures in an ACC have any persistent detrimental ocular physical effects.

METHODS

Participants underwent 3 exposures to RW in an ACC. Ocular symptoms of itching and tearing were self-assessed. Ocular redness and lid swelling were assessed by trained ophthalmic technicians. Complete ophthalmic examinations (COEs) were performed by an ophthalmologist.

RESULTS

A total of 188 of 201 participants (93%) developed an ocular redness score of 2 or more in each eye in ACC exposure 1. Reproducibility of redness occurred in approximately 70% of individuals completing ACC exposures 1 through 3. There were no significant changes between baseline COE and end of study COE. Phenotypes were identified by redness responses during and after exposure. Baseline total ocular symptom scores, at 24 hours after a priming exposure, were identified as late-phase reactions rather than enhanced sensitivity.

CONCLUSION

When assessed by trained professionals, AC was present with a very high frequency in selected individuals allergic to RW monitored in an ACC. Intrasubject reproducibility of redness was consistent across 3 ACC allergen exposures. Phenotypes were identified as early-phase responses, protracted early-phase responses, dual responses, and late-phase responses.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT02079649.

The dietary form of choline during lactation affects maternal immune function in rats

PURPOSE

The present study was designed to determine the effects of both choline form and availability on maternal immune function during lactation.

METHODS

Sprague-Dawley rats were randomized to one of the three diets 24-48 h before parturition and fed ad libitum until 21 days postnatal: 1 g/kg choline as free choline (C, n = 11), the current form, and amount of choline in commercial diets; 1 g/kg choline as phosphatidylcholine (PC1, n = 11); or 2.5 g/kg choline as PC (PC2.5, n = 8). Choline metabolites in offspring stomach contents were quantified. At 21 days, lymphocytes from mothers' mesenteric lymph nodes and spleens were isolated and phenotypes and ex vivo cytokine production after mitogen exposure were determined.

RESULTS

There was a higher proportion of choline and a lower proportion of lyso-PC in stomach contents (representing dam's milk) of C pups compared to PC1. In the mesenteric lymph nodes, feeding PC1 compared to C led to a higher IL-2 production after Concanavalin A (ConA) stimulation and a higher proportion of T cells (CD3+) and a lower proportion of B cells [immunoglobulin (Ig)κ, CD45RA+, and IgM+; P < 0.05]. Splenocytes from the PC1 group produced more IL-6 and TNF-α after lipopolysaccharides stimulation compared to C (P < 0.05). Splenocytes from the PC2.5 group produced more IL-2 and IL-6 after ConA stimulation compared to PC1 (P < 0.05).

CONCLUSIONS

Feeding choline as PC in the maternal diet improved the ability of immune cells to respond ex vivo to mitogens and increasing the amount of PC in the diet further improved T cell proliferation.

Preservation of epithelial cell barrier function and muted inflammation in resistance to allergic rhinoconjunctivitis from house dust mite challenge

BACKGROUND

An emerging paradigm holds that resistance to the development of allergic diseases, including allergic rhinoconjunctivitis, relates to an intact epithelial/epidermal barrier during early childhood. Conceivably, the immunologic and genomic footprint of this resistance is preserved in nonatopic, nonallergic adults and is unmasked during exposure to an aeroallergen.

OBJECTIVE

The aim of this study was to obtain direct support of the epithelial/epidermal barrier model for allergic rhinoconjunctivitis.

METHODS

Twenty-three adults allergic to house dust mites (HDMs) (M+) and 15 nonsensitive, nonallergic (M-) participants completed 3-hour exposures to aerosolized HDM (Dermatophagoides pteronyssinus) powder on 4 consecutive days in an allergen challenge chamber. We analyzed: (1) peripheral blood leukocyte levels and immune responses; and (2) RNA sequencing-derived expression profiles of nasal cells, before and after HDM exposure.

RESULTS

On HDM challenge: (1) only M+ persons developed allergic rhinoconjunctivitis symptoms; and (2) peripheral blood leukocyte levels/responses and gene expression patterns in nasal cells were largely concordant between M+ and M- participants; gross differences in these parameters were not observed at baseline (pre-exposure). Two key differences were observed. First, peripheral blood CD4⁺ and CD8⁺ T-cell activation levels initially decreased in M- participants versus increased in M+ participants. Second, in M- compared with M+ participants, genes that promoted epidermal/epithelial barrier function (eg, filament-aggregating protein [filaggrin]) versus inflammation (eg, chemokines) and innate immunity (interferon) were upregulated versus muted, respectively.

CONCLUSION

An imprint of resistance to HDM challenge in nonatopic, nonallergic adults was muted T-cell activation in the peripheral blood and inflammatory response in the nasal compartment, coupled with upregulation of genes that promote epidermal/epithelial cell barrier function.

Efficacy and safety of beclomethasone dipropionate nasal aerosol in children with perennial allergic rhinitis

BACKGROUND

Beclomethasone dipropionate (BDP) nasal aerosol (non-aqueous) is approved for management of seasonal and perennial allergic rhinitis (PAR) in adolescents and adults.

OBJECTIVE

To evaluate the efficacy and safety of BDP nasal aerosol at 80 μg/day in children with PAR.

METHODS

This 12-week, phase 3, double-blinded, placebo-controlled, parallel-group study randomized 547 children (4-11 years old) with PAR to once-daily BDP nasal aerosol at 80 μg/day or placebo. The primary end point was change from baseline in average morning and evening reflective total nasal symptom score (rTNSS) during the first 6 weeks of treatment in patients 6 to 11 years old. Changes from baseline in average morning and evening instantaneous TNSS (iTNSS) in children 6 to 11 years old and average rTNSS and iTNSS in children 4 to 11 years old were assessed during the first 6 weeks of treatment.

RESULTS

Improvements were significantly greater with BDP nasal aerosol than with placebo during the first 6 weeks of treatment in children 6 to 11 years old in average morning and evening rTNSS and iTNSS (mean treatment difference -0.66 [P = .002] and -0.58 [P = .004], respectively). Improvements in average morning and evening rTNSS and iTNSS also were significantly greater in patients 4 to 11 years receiving BDP nasal aerosol than with placebo during the first 6 weeks of treatment (P = .002 and P = .004, respectively). Similar improvements were seen during 12 weeks of treatment. The safety profile of BDP nasal aerosol was comparable to that of placebo.

CONCLUSION

The BDP nasal aerosol at 80 μg/day in children 4 to 11 years old was well tolerated and effective in controlling nasal symptoms of PAR.

TRIAL REGISTRATION

www.clinicaltrials.gov, identifier NCT01783548.

Cockroach sensitization mitigates allergic rhinoconjunctivitis symptom severity in patients allergic to house dust mites and pollen

BACKGROUND

Modifiers of symptom severity in patients with allergic rhinoconjunctivitis (AR) are imprecisely characterized. The hygiene hypothesis implicates childhood microbial exposure as a protective factor. Cockroach sensitization (C+) might be a proxy for microbial exposure.

OBJECTIVE

We sought to determine whether C+ assayed by means of skin prick tests influenced AR symptom severity in controlled and natural settings.

METHODS

Total symptom scores (TSSs) were recorded by 21 participants with house dust mite allergy (M+) in the natural setting and during repeated exposures of 3 hours per day to house dust mite allergen in an allergen challenge chamber (ACC). In M+ participants the peripheral blood and nasal cells were assayed for T-cell activation and transcriptomic profiles (by using RNA sequencing), respectively. Participants allergic to mountain cedar (n = 21), oak (n = 34), and ragweed (n = 23) recorded TSSs during separate out-of-season exposures to these pollens (any pollen sensitization [P+]) in the ACC; a subset recorded TSSs in the pollination seasons.

RESULTS

The hierarchy of TSSs (highest to lowest) among M+ participants tracked the following skin prick test sensitization statuses: M+P+C- > M+P+C+ > M+P-C- > M+P-C+. In nasal cells and peripheral blood the immune/inflammatory responses were rapidly resolved in M+P+C+ compared with M+P+C- participants. Among those allergic to pollen, C+ was associated with a lower TSS during pollen challenges and the pollination season. After aggregated analysis of all 4 ACC studies, C+ status was associated with a 2.8-fold greater likelihood of a lower TSS compared with C- status (odds ratio, 2.78; 95% CI, 1.18-6.67; P = .02).

CONCLUSIONS

C+ status is associated with mitigation of AR symptom severity in adults with AR.

The mountain cedar model in clinical trials of seasonal allergic rhinoconjunctivitis

BACKGROUND

Clinical trials of seasonal allergic rhinoconjunctivitis use the mountain cedar (Juniperus ashei) season as the predominate model.

OBJECTIVE

To evaluate clinical trials of rhinoconjunctivitis using mountain cedar, to present analysis of pollen counts during 18 seasons, and to discuss the model.

METHODS

The medical literature was searched for clinical trials performed using mountain cedar either in or out of season. Pollen counts were recorded and analyzed for the duration of 18 seasons.

RESULTS

Thirty-eight trials were identified. Of these, 1 evaluated onset of allergy, 8 were immunotherapy trials, 28 were pharmaceutical clinical trials, and 1 studied symptoms elicited in a pollen challenge chamber trial. Many generic equivalency trials are unreported. In the 18 years of counts in the Texas Hill Country, a dependable and intense pollen density was present in every season. The combination of dependable seasons without confounding pollens, the large number of allergic patients, and the ability to concentrate resources in one geographic area has made mountain cedar allergy a mainstay for therapeutic trials for allergic rhinoconjunctivitis.

CONCLUSION

Mountain cedar allergy presents a dependable and durable model of allergic rhinoconjunctivitis.

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.