Mena Soliman

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.

Nasal allergen challenge studies of allergic rhinitis: a guide for the practicing clinician

INSTRUCTIONSCredit can now be obtained, free for a limited time, by reading the review article in this issue and completing all activity components.Please note the instructions listed below: Review the target audience, learning objectives and all disclosures. Complete the pre-test online at http://www.annallergy.org (click on the CME heading). Followtheonlineinstructionstoreadthefullversionofthearticle;reflectonallcontentastohowitmaybeapplicabletoyourpractice. Complete the post-test/evaluation and claim credit earned; at this time, you will have earned up to 1.0 AMA PRA Category 1 Credit

The Allergic Rhinitis - Clinical Investigator Collaborative (AR-CIC): nasal allergen challenge protocol optimization for studying AR pathophysiology and evaluating novel therapies

BackgroundThe Nasal Allergen Challenge (NAC) model allows the study of Allergic Rhinitis (AR) pathophysiology and the proof of concept of novel therapies. The Allergic Rhinitis – Clinical Investigator Collaborative (AR-CIC) aims to optimize the protocol, ensuring reliability and repeatability of symptoms to better evaluate the therapies under investigation.Methods20 AR participants were challenged, with 4-fold increments of their respective allergens every 15 minutes, to determine the qualifying allergen concentration (QAC) at which the Total Nasal Symptom Score (TNSS) of ≥10/12 OR a Peak Nasal Inspiratory Flow (PNIF) reduction of ≥50% from baseline was achieved. At the NAC visit, the QAC was used in a single challenge and TNSS and PNIF were recorded at baseline, 15 minutes, 30 minutes, 1 hour, and hourly up to 12 hours. 10 additional ragweed allergic participants were qualified at TNSS of ≥8/12 AND ≥50% PNIF reduction; the Cumulative Allergen Challenge (CAC) of all incremental doses was used during the NAC visit. 4 non-allergic participants were challenged with the highest allergen concentration.ResultsIn the QAC study, a group qualified by only meeting PNIF criteria achieved lower TNSS than those achieving either TNSS criteria or PNIIF+TNSS (p<0.01). During the NAC visit, participants in both studies reached their peak symptoms at 15minutes followed by a gradual decline, significantly different from non-allergic participants. The “PNIF only” group experienced significantly lower TNSS than the other groups during NAC visit. QAC and CAC participants did not reach the same peak TNSS during NAC that was achieved at screening. QAC participants qualifying based on TNSS or TNSS+PNIF managed to maintain PNIF scores.ConclusionsParticipants experienced reliable symptoms of AR in both studies, using both TNSS and PNIF reduction as part of the qualifying criteria proved better for qualifying participants at screening. Phenotyping based on pattern of symptoms experienced is possible and allows the study of AR pathophysiology and can be applied in evaluation of efficacy of a novel medication. The AR-CIC aims to continue to improve the model and employ it in phase 2 and 3 clinical trials.

Repeatability of nasal allergen challenge results – further validation of the allergic rhinitis clinical investigator collaborative (AR-CIC) protocols

BACKGROUND Nasal allergen challenge (NAC) models have been used to study allergic rhinitis and new therapies. Symptoms and biological samples can be evaluated at time points after allergen exposure. OBJECTIVE To verify protocol repeatability and adequate interval between allergen exposures. METHODS Ten ragweed allergic participants were exposed to incrementally increasing dosages of ragweed allergen intranasally until they achieved a total nasal symptom score (TNSS) of 8 of 12 and a peak nasal inspiratory flow (PNIF) of 50% reduction or more from baseline. Three weeks later, participants were challenged with a cumulative dose equal to the sum of all the allergen doses received at screening. TNSS and PNIF were recorded at regular intervals, including a 24-hour assessment. A subsequent visit was conducted after a further 3 weeks. Nasal secretion samples were collected for cytokine and eosinophil quantification. RESULTS Nine participants completed all visits. TNSS and PNIF responses followed previous patterns, with an initial peak at 30 minutes followed by a gradual decline. Most participants reported similar patterns at both NAC visits, although some did not demonstrate the same phenotype at both visits. Some experienced a secondary symptom increase 24 hours after NAC. Eosinophil and cytokine sections followed a similar pattern at both NAC visits. CONCLUSION NAC is an adequate method for modeling AR in humans, demonstrating appropriate repeatability of symptoms, nasal mucosal eosinophil, and cytokines. The 24-hour time point, previously not studied in our model, may be beneficial in evaluation of long-acting medications. This three-week interval NAC model will be beneficial for studies in which before and after treatment comparisons are desired.

The Role of Synthetic Peptide Immuno-Regulatory Epitope (SPIRE) in the Treatment of Allergic Disease

Opinion statementImmunotherapy has been used for over a century for the treatment of allergic rhinitis, starting with the administration of whole allergens which are still in use today. Up-titration of allergen concentrations is thought to induce immune-tolerance, reducing symptoms upon exposure of the same allergen in the natural environment. More recently, peptide immunotherapy research aims to reduce sensitization to the allergen while utilizing a much shorter treatment schedule and avoiding the risk of anaphylactic reactions associated with whole allergen administration. Other immunotherapies undergoing clinical trials utilize linear joined peptides of the natural antigen, which are thought to avoid triggering anaphylaxis by selectively joining non-IgE binding allergen proteins. These novel therapies have been investigated using a variety of methods, including at controlled allergen challenge facilities (CACF) and in phase 3 trials in the “real world” setting. Experimental phase 2 trial designs were also used, the nasal allergen challenge (NAC) protocols, involving the direct exposure of the nasal mucosa to the allergen. The mechanism of action of peptide immunotherapies is thought to vary from that of conventional immunotherapies, though more research is needed to understand how desensitization occurs in each case. A shift from CD4+ to CD8+ Th cells is thought to be one way to explain this and is backed by change in cytokine expression in various experimental models.

The Allergic Rhinitis - Clinical Investigator Collaborative (AR-CIC) - optimizing the Nasal Allergen Challenge (NAC) model

Background We sought to optimize the Nasal Allergen Challenge (NAC) model to ensure reliability and repeatability of results by modifying the qualifying criteria and allergen concentration during the challenge. Methods 20 Allergic Rhinitis (AR) participants underwent NAC to determine the concentration at which a Total Nasal Symptom Score (TNSS) of 10/12 OR a Peak Nasal Inspiratory Flow (PNIF) reduction of 50 % was achieved. 4-fold increases in allergen concentration were administered every 15 minutes until qualification criteria were met. The Qualifying Allergen Concentration (QAC) reached was used as a single challenge dose at the subsequent NAC visit. 10 additional ragweed allergic and 4 non-allergic participants were qualified at a TNSS of 8/12 AND a PNIF reduction of 50%. Cumulative Allergen Concentration (CAC) of all incremental doses was used during the subsequent NAC visit. Participants recorded TNSS and PNIF at baseline, 15 minutes, 30 minutes, 1 hour and hourly afterwards up to 12 hours post-challenge during the NAC visit. Results QAC study participants qualifying only based on PNIF reduction had significantly lower TNSS scores than those qualifying on TNSS only or TNSS+PNIF (p<0.01). Participants in both studies’ NAC visit reached peak TNSS at 15 minutes post-challenge followed by a gradual symptom decline, while the “PNIF only” group had significantly lower TNSS compared to others. All 3 groups experienced a decline in peak TNSS following NAC compared to screening, although groups qualifying on TNSS and TNSS+PNIF maintained their PNIF scores. Conclusion The NAC model is well-suited to study AR symptoms. TNSS and PNIF are complementary and must be integrated in the qualifying criteria. Further protocol modifications, such as with multiple allergen challenges during the NAC visit, may produce even more repeatable results. Through optimizing the NAC protocol, the model achieves reproducible results and becomes more reliable; suitable for testing new medications in clinical trials.

Mediators of allergic rhinitis: optimization of RNA isolation, reverse transcription, and qPCR protocols

Background Optimizing methods for the study of allergic rhinitis (AR), especially when using samples likely containing small amounts of material for analysis, ensures the integrity of results that may potentially enhance the understanding of AR disease mechanisms. In order to conduct future mRNA expression analysis, examining the differential expression of AR mediators such as IL33, TSLPR, HPGDS ,a ndCRTH2 at baseline and 6 hours following Nasal Allergen Challenge (NAC) in allergic individuals, this study aims to optimize the RNA isolation, reverse transcription (RT), and qPCR protocols used for the study of nasal mucosal samples. Methods Several RNA isolation and RT kits were evaluated using nasal scrapings from healthy individuals, similar to those collected from allergic participants. These kits were evaluated based on the yield and purity of RNA and cDNA, assessed using spectrophotometry, qPCR amplification, and gel electrophoresis. Reference gene analysis using cDNA isolated from allergic participants was conducted using qPCR and the statistical software GenEx (MultID). Primer design and evaluation of primers for the targets of interest—IL33, TSLPR, HPGDS ,a nd CRTH2—was also pursued. Results RNA isolation and RT kit optimization determined that the Life Technologies-Qiagen (LT-Q) kit combination produced cDNA with maximal purity and qPCR efficiency compared with the other kit combinations evaluated. Reference gene analysis demonstrated that expression of ubiquitin C (UBC) showed limited variability among the differing conditions (time point and study) of nasal sample collection. Primer evaluation yielded inconsistent results. Conclusions Future processing of nasal scraping samples should use the optimal LT-Q kit combination. Following successful primer evaluation, the expression levels of the targets of interest in the allergic nasal mucosal cDNA samples at both baseline and 6h post-NAC will be conducted via the optimized qPCR reaction, using UBC as a reference gene.