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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.

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.

Background Bermuda grass is a prevalent allergen that flourishes in tropical climates. Bermuda grass exposure is traditionally believed to be low in Ontario due to the colder environment. However, high rates of Bermuda grass sensitization have been observed in Kingston, Ontario. Objective We sought to investigate whether Bermuda grass allergens can provoke allergic rhinitis(AR) symptoms in sensitized participants from south-eastern Ontario and determine if the nasal allergen challenge(NAC) model is appropriate to study Bermuda grass-induced AR. Methods Twenty-one Bermuda grass sensitized and 12 non-allergic participants completed a titrated NAC with increasing concentrations of Bermuda grass allergens at a screening visit. Total nasal symptom score(TNSS) and peak nasal inspiratory flow(PNIF) were collected before allergen exposure and 10 minutes after the delivery of each concentration. Twelve allergic participants that met the qualifying criteria (TNSS≥8 and PNIF fall≥50%) and 11 non-allergic controls returned for a single-dose NAC visit. Results At the titrated NAC, 19 out of 21 sensitized participants met the criteria of a positive allergic response when challenged. During the single-dose NAC, allergic participants had significantly greater TNSS between 15 minutes and 3 hours post NAC compared to controls. Likewise, allergic participants had significantly increased nasal lavage eosinophils at both 1 and 6 hours post NAC. Bermuda grass specific IgE was significantly increased in allergic participants at the NAC visit when compared to the screening visit. Conclusion Although Bermuda grass is a non-native allergen in Ontario, Bermuda grass allergens can induce AR symptoms in sensitized participants and the NAC model is appropriate to study Bermuda grass-induced AR.

Nasal allergen challenge (NAC) is a human model of allergic rhinitis (AR) that delivers standardized allergens locally to the nasal mucosa allowing clinical symptoms and biospecimens such as peripheral blood to be collected. Although many studies have focused on local inflammatory sites, peripheral blood, an important mediator and a component of the systemic immune response, has not been well studied in the setting of AR. We sought to investigate immune gene signatures in peripheral blood collected after NAC under the setting of AR. Clinical symptoms and peripheral blood samples from AR subjects were collected during NAC. Fuzzy c-means clustering method was used to identify immune gene expression patterns in blood over time points (before NAC and 1, 2, and 6 h after NAC). We identified and validated seven clusters of differentially expressed immune genes after NAC onset. Clusters 2, 3, and 4 were associated with neutrophil and lymphocyte frequencies and neutrophil/lymphocyte ratio after the allergen challenge. The patterns of the clusters and immune cell frequencies were associated with the clinical symptoms of the AR subjects and were significantly different from healthy nonallergic subjects who had also undergone NAC. Our approach identified dynamic signatures of immune gene expression in blood as a systemic immune response associated with clinical symptoms after NAC. The immune gene signatures may allow cross-sectional investigation of the pathophysiology of AR and may also be useful as a potential objective measurement for diagnosis and treatment of AR combined with the NAC model.

Retraction This meeting abstract [1], published in the Canadian Society of Allergy and Clinical Immunology and AllerGen Abstracts 2014 supplement, has been retracted from Allergy, Asthma & Clinical Immunology by the authors. The meeting abstract has previously been published in Journal of Allergy and Clinical Immunology [2] and was inadvertently submitted to Allergy, Asthma & Clinical Immunology as part of the supplement. The authors apologise for any inconvenience that this may have caused.

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.

Background A custom digital imagery method for real time identification and counting of pollen was qualitatively evaluated in the Environmental Exposure Unit (EEU). Methods Airborne grass pollen was collected in the EEU via a Rotorod ® impact sampler. The pollen grains on each sampling rod were counted using both traditional and headsup microscopy. The heads-up technique incorporated a microscope camera to create an on-screen image of the sampling rod. Firstly, unique images were created by manually advancing the stage, without duplicating previously captured pollen grains. Well-defined, sharp images were obtained by fine focus and zoom combinations to enhance certainty and recognition speed. Secondly, using a custom application, each pollen grain was identified and counted on-screen by “point and click” or “screen touch”, simultaneously counting and permanently anchoring opaque dots to the pollen grain locations. Counts were stored in real time on a central database. Results Increased clarity of the polle ng rains resulted in higher counting accuracy. Duplicate counting of pollen grains was eliminated by digitally labelling counted grains. Additional need for manual counting devices, commonly associated with mechanical and human errors, was eliminated. Error free counts can be obtained with increased speed, therefore, improving the overall efficiency of the process and the EEU system as a whole. Conclusions This validated heads-up counting technique will allow for an increased response time to changes in the EEU pollen levels. This advancement could also enhance pollen counting processes followed by others using direct microscopy pollen counting techniques.

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Background Cytokines have been shown to be important signal molecules in the development of allergy and asthma, especially the regulatory cytokine IL-10, which has been shown to correlate with higher risk of allergy development in children [1]. Research results regarding cytokine levels in umbilical cord blood plasma vary greatly; some studies find the concentration of cytokines detectable whereas other studies do not. The purpose of this pilot study was to determine if cytokines could be measured from cord blood plasma using IL-10 ELISAs and xMAP Luminex assay.

* Correspondence: 8yz7@queensu.ca Department of Biomedical and Molecular Sciences/Medicine, Queen’s University, Kingston, ON, K7L 3N6, Canada Figure 1 IDO1 gene expression fold changes relative to plain media control. IDO1 expression levels were normalized to HPRT1 expression. The error bars represent the standard error of the mean. Numbers per stimulation group are as indicated beneath the graph. Cultures of atopic and non-atopic AMNCs were plated at 7.5x10 cells per condition. Following 5.5 hours incubation with either plain media, 1 μg/ml IFN-g, or 1 μg/ml IFN-g and 10 ng/ml CSE, cells were lysed for RNA extraction. RNA was reverse transcribed and cDNA levels were analyzed. Zhu et al. Allergy, Asthma & Clinical Immunology 2014, 10(Suppl 1):A72 http://www.aacijournal.com/content/10/S1/A72 ALLERGY, ASTHMA & CLINICAL IMMUNOLOGY

A1 Role of fibrocytes in allergic rhinitis Marie-Ève Côté, Marie-Ève Boulay, Sophie Plante, Jamila Chakir, Louis-Philippe Boulet A2 Patterns of aeroallergens sensitization in Northern Alberta Hanan Ahmed, Maria-Beatriz Ospina, Kyriaki Sideri, Harissios Vliagoftis A3 Addressing acceptable risk for adolescents with Food-Induced Anaphylaxis (FIA) Sara F. Johnson, Roberta L. Woodgate A4 Outcomes of matched related and unrelated bone marrow transplantation after reduced-toxicity conditioning for children suffering from Chronic Granulomatous Disease Guilhem Cros, Pierre Teira, Sonia Cellot, Henrique Bittencourt, Helene Decaluwe, Marie France Vachon, Michel Duval, Elie Haddad A5 Outcomes of patients with severe combined immunodeficiency (SCID) prior to and after initiation of newborn screening for SCID in Ontario Vy H.D. Kim, Anne Pham-Huy, Eyal Grunebaum A6 Detection of regulatory B cells in the airways of subjects with asthma John-Paul Oliveria, Stephanie Phan, Mark W. Tenn, Damian Tworek, Steven G. Smith, Adrian J. Baatjes, Caitlin D. Obminski, Caroline E. Munoz, Tara X. Scime, Roma Sehmi, Gail M Gauvreau A7 Characterization of IgE-expressing B cells in the airways and peripheral blood of allergic asthmatic subjects John-Paul Oliveria, Stephanie Phan, Mark W. Tenn, Brittany M Salter, Steven G Smith, Caitlin D Obminski, Caroline E Munoz, Abbey Schlatman, Tara X Scime, Rick Watson, Roma Sehmi, Gail M Gauvreau A8 Pregnancy: could it be a risk factor for primary immunodeficient patients Roya Sherkat, Razieh Khoshnevisan, Saba Sheikhbahaei A9 Clinical experience with Octagam: a Canadian retrospective chart review Stephen Betschel, Richard Warrington, Robert Schellenberg A10 Kounis syndrome secondary to contrast media with inferior ST elevations and bilateral ischemic stroke Michael N Fein, Jean-Philippe Pelletier A11 Honey bee venom immunotherapy ineffective in bumble bee-induced anaphylaxis: case report and review of literature Manstein Kan, Robert Schellenberg A12 Delayed immune reconstitution occurring after multiple immune complications of hematological stem cell transplantation for a leaky SCID Roxane Labrosse, Guilhem Cros, Pierre Teira, Henrique Bittencourt, Helene Decaluwe, Michel Duval, Elie Haddad A13 Comparison of Three Case Reports of Acquired Angioedema: presentation, management and outcome Raymond Mak, James Loh, Amin Kanani A14 Sitagliptin-associated angioedema not related to concurrent use of ARB or ACE inhibitor Dominik A. Nowak, Paul K. Keith A15 Sneddon-Wilkinson subcorneal pustular dermatosis associated with an IgA monoclonal gammopathy Daniel Pannozzo, Dominik A. Nowak, Hermenio C. Lima A16 Omalizumab can be effective in patients with allergic bronchopulmonary aspergillosis Diana Pham, Hoang Pham, Gonzalo G. Alvarez, Istvan T. Bencze, Krishna B. Sharma, Mark Smith, Shawn Aaron, Jennifer Block, Tara Keays, Judith Leech, David Schneidermen, Jodi Cameron, Jennifer Forgie, Alicia Ring, John W. O’Quinn, Stephanie Santucci, William H. Yang A17 Efficacious use of omalizumab in the treatment of cystic fibrosis Diana Pham, Hoang Pham, Ena Gaudet, Shawn Aaron, Stephanie Santucci, William H. Yang A18 HAE with normal C1-INH with inconsistent response to C1 esterase inhibitor infusion but reliably responsive to icatibant Hoang Pham, Stephanie Santucci, William H. Yang A19 Anaphylaxis reaction to lactase enzyme Mathew R. Voisin, Rozita Borici-Mazi A20 Risk of solid tumor malignancies in patients with primary immune deficiency Kateryna Vostretsova, Donald F. Stark A21 Is it time to adopt the chromogenic assay for measuring C1 esterase inhibitor function in patients with HAE Type 2? Elizabeth Yeboah, Paul K. Keith A22 Emergency department visits for anaphylaxis and allergic reactions Michelle Martin-Rhee, Cheryl Gula, Clare Cheng, Geoff Paltser A23 START: Susceptibility To food Allergies in a Registry of Twins Alizée Dery, Ann Clarke, Kari Nadeau, Laurie Harada, Kimberley Weatherall, Celia Greenwood, Denise Daley, Yuka Asai, Moshe Ben-Shoshan A24 Qualifying the diagnostic approach employed by allergists when managing patients with self-diagnosed non-celiac gluten sensitivity (NCGS) Lee Horgan, Teresa Pun A25 Retrospective analysis on the agreement between skin prick test and serum food specific IgE antibody in adults with suspected food allergy Ling Ling, Maria B. Ospina, Kyriaki Sideri, Harissios Vliagoftis A26 Staple food hypersensitivity from infancy to adolescence: a report from the BAMSE cohort Jennifer L.P. Protudjer, Mirja Vetander, Marianne van Hage, Ola Olén, Magnus Wickman, Anna Bergström A27 Evaluating the impact of supervised epinephrine autoinjector administration during food challenges on perceived parent confidence Timothy Teoh, Christopher Mill, Tiffany Wong, Ingrid Baerg, Angela Alexander, Kyla J. Hildebrand, John Dean, Boris Kuzeljevic, Edmond S. Chan A28 Local immunoglobulin production to Aspergillus fumigatus cystic fibrosis Jonathan Argeny, Mia Gona-Hoepler, Petra Fucik, Edith Nachbaur, Saskia Gruber, Reto Crameri, Andreas Glaser, Zsolt Szépfalusi, Claudio Rhyner, Thomas Eiwegger A29 Extract consumption with skin prick test (SPT) devices Greg. Plunkett, Brad Mire A30 Evaluation of our cases with nonsteroidal anti-inflammatory drug reactions Mehtap Yazicioglu, Ceren Can, Gokce Ciplak A31 Reasons for referral and final diagnoses in a tertiary care pediatric allergy clinic Victoria E. Cook, Kyla J. Hildebrand, Elodie Portales-Casamar, Christopher Mill, Edmond S. Chan A32 Internist referral practices for inpatients with self-reported penicillin allergies at a tertiary care teaching hospital Michael N Fein, Emil P Nashi A33 Assessing the risk of reactions in children with a negative oral challenge after a subsequent use of amoxicillin Sofianne Gabrielli, Christopher Mill, Marie-Noel Primeau, Christine Lejtenyi, Elena Netchiporouk, Alizee Dery, Greg Shand, Moshe Ben-Shoshan A34 Validity of self-reported penicillin allergies Erica Hoe, Joel Liem A35 Effectiveness of allergy-test directed elimination diets in eosinophilic esophagitis Jason K. Ko, David J.T. Huang, Jorge A. Mazza A36 Allergy testing and dietary management in pediatric eosinophilic esophagitis (EoE): A retrospective review of a tertiary Canadian centre’s experience Mary McHenry, Anthony Otley,Wade Watson A37 Visualizing the impact of atopic and allergic skin disease Dominik A. Nowak, John N. Kraft A38 Cystic fibrosis with and without nasal polyposis in pediatric patients: a cross-sectional comparative study Mihaela Paina, Ahmed A. Darwish Hassan, Delia Heroux, Lynn Crawford, Gail Gauvreau, Judah Denburg, Linda Pedder, Paul K. Keith A39 Evaluation of macrolide antibiotic hypersensitivity: the role of oral challenges in children Bahar Torabi, Marie-Noel Primeau, Christine Lejtenyi, Elaine Medoff, Jennifer Mill, Moshe Ben-Shoshan A40 Venom allergy testing: is a graded approach necessary? Jaclyn A. Quirt, Xia Wen, Jonathan Kim, Angel Jimenez Herrero, Harold L. Kim A41 The role of oral challenges in evaluating cephalosporin hypersensitivity reactions in children Magdalena J. Grzyb, Marie-Noël Primeau, Christine Lejtenyi, Elaine Medoff, Jennifer Mill, Moshe Ben-Shoshan A42 Breastfeeding and infant wheeze, atopy and atopic dermatitis: findings from the Canadian Healthy Infant Longitudinal Development Study Meghan B. Azad, Zihang Lu, Allan B. Becker, Padmaja Subbarao, Piushkumar J. Mandhane, Stuart E. Turvey, Malcolm R. Sears, the CHILD Study Investigators A43 IL33 DNA methylation in bronchial epithelial cells is associated to asthma Anne-Marie Boucher-Lafleur, Valérie Gagné-Ouellet, Éric Jacques, Sophie Plante, Jamila Chakir, Catherine Laprise A44 NRF2 mediates the antioxidant response to organic dust-induced oxidative stress in bronchial epithelial cells Michael Chen, Toby McGovern, Mikael Adner, James G. Martin A45 The effects of perinatal distress, immune biomarkers and mother-infant interaction quality on childhood atopic dermatitis (rash) at 18 months Nela Cosic, Henry Ntanda, Gerald Giesbrecht, Anita Kozyrskyj, Nicole Letourneau A46 Examining the immunological mechanisms associated with cow’s milk allergy Bassel Dawod, Jean Marshall A47 Tryptase levels in children presenting with anaphylaxis to the Montréal Children’s Hospital Sarah De Schryver, Michelle Halbrich, Ann Clarke, Sebastian La Vieille, Harley Eisman, Reza Alizadehfar, Lawrence Joseph, Judy Morris, Moshe Ben-Shoshan A48 Secondhand tobacco smoke exposure in infancy and the development of food hypersensitivity from childhood to adolescence Laura Y. Feldman, Jesse D. Thacher, Inger Kull, Erik Melén, Göran Pershagen, Magnus Wickman, Jennifer L. P. Protudjer, Anna Bergström A49 Combined exposure to diesel exhaust and allergen enhances allergic inflammation in the bronchial submucosa of atopic subjects Ali Hosseini, Tillie L. Hackett, Jeremy Hirota, Kelly McNagny, Susan Wilson, Chris Carlsten A50 Comparison of skin-prick test measurements by an automated system against the manual method Saiful Huq, Rishma Chooniedass, Brenda Gerwing, Henry Huang, Diana Lefebvre, Allan Becker A51 The accurate identification and quantification of urinary biomarkers of asthma and COPD through the use of novel DIL- LC-MS/MS methods Mona M. Khamis, Hanan Awad, Kevin Allen, Darryl J. Adamko, Anas El-Aneed A52 Systemic immune pathways associated with the mechanism of Cat-Synthetic Peptide Immuno-Regulatory Epitopes, a novel immunotherapy, in whole blood of cat-allergic people Young Woong Kim, Daniel R. Gliddon, Casey P. Shannon, Amrit Singh, Pascal L. C. Hickey, Anne K. Ellis, Helen Neighbour, Mark Larche, Scott J. Tebbutt A53 Reducing the health disparities: online support for children with asthma and allergies from low-income families Erika Ladouceur, Miriam Stewart, Josh Evans, Jeff Masuda, Nicole Letourneau, Teresa To, Malcolm King A54 Epigenetic association of PSORS1C1 and asthma in the Saguenay-Lac-Saint-Jean asthma study Miriam Larouche, Liming Liang, Catherine Laprise A55 IL-33 induces cytokine and chemokine production in human mast cells Stephanie A. Legere, Ian D. Haidl, Jean-Francois Legaré, Jean S. Marshall A56 Reference ranges for lung clearance index from infancy to adolescence for Canadian population Zihang Lu, Malcolm Sears, Theo J. Moraes, Felix Ratjen, Per Gustafsson, Wendy Lou, Padmaja Subbarao A57 Kingston Allergy Birth Cohort: cohort profile and mother/child characteristics to age 2 Michelle L. North, Elizabeth Lee, Vanessa Omana, Jenny Thiele, Jeff Brook, Anne K. Ellis A58 Cow’s milk protein specific IgE, IgA and IgG4 as a predictor of outcome in oral immunotherapy Tanvir Rahman, Duncan Lejtenyi, Sarah De Schryver, Ryan Fiter, Ciriaco Piccirillo, Moshe Ben-Shoshan, Bruce Mazer A59 Age of peanut introduction and development of reactions and sensitization to peanut Elinor Simons, Allan B. Becker, Rishma Chooniedass, Kyla Hildebrand, Edmond S. Chan, Stuart Turvey, Padmaja Subbarao, Malcolm Sears A60 Multi-omic blood biomarker signatures of the late phase asthmatic response Amrit Singh, Casey P. Shannon, Young Woong Kim, Mari DeMarco, Kim-Anh Le Cao, Gail M. Gauvreau, J. Mark FitzGerald, Louis-Philippe Boulet, Paul M. O’Byrne, Scott J. Tebbutt A61 Early life gut microbial alterations in children diagnosed with asthma by three years of age Leah T. Stiemsma, Marie-Claire Arrieta, Jasmine Cheng, Pedro A. Dimitriu, Lisa Thorson, Sophie Yurist, Boris Kuzeljevic, Diana L. Lefebvre, Padmaja Subbarao, Piush Mandhane, Allan Becker, Malcolm R. Sears, Kelly M. McNagny, Tobias Kollmann, the CHILD Study Investigators, William W. Mohn, B. Brett Finlay, Stuart E. Turvey A62 The relationship between food sensitization and atopic dermatitis at age 1 year in a Canadian birth cohort Maxwell M. Tran, Diana L. Lefebvre, Chinthanie F. Ramasundarahettige, Allan B. Becker, Wei Hao Dai, Padmaja Subbarao, Piush J. Mandhane, Stuart E. Turvey, Malcolm R. Sears A63 Allergen inhalation enhances Toll-like receptor-induced thymic stromal lymphopoietin receptor expression by hematopoietic progenitor cells in mild asthmatics Damian Tworek, Delia Heroux, Seamus N. O’Byrne, Paul M. O’Byrne, Judah A. Denburg A64 The Allergic Rhinitis Clinical Investigator Collaborative – replicated eosinophilia on repeated cumulative allergen challenges in nasal lavage samples Laura Walsh, Mena Soliman, Jenny Thiele, Lisa M. Steacy, Daniel E. Adams, Anne K. Ellis A65 The CHILD Study: optimizing subject retention in pediatric longitudinal cohort research Linda Warner, Mary Ann Mauro, Robby Mamonluk, Stuart E. Turvey A66 Differential expression of C3a and C5a in allergic asthma ChenXi Yang, Amrit Singh, Casey P. Shannon, Young Woong Kim, Ed M. Conway, Scott J. Tebbutt

Background The Allergic Rhinitis Clinical Investigator Collaborative (AR-CIC) is a Canadian multi-center initiative with the primary goal of performing standardized nasal allergen challenge (NAC) to study the anti-allergic effects of novel therapeutic agents for allergic rhinitis (AR). The model further allows identification of potential mechanisms of allergic disease and biomarkers. In this study we examined differential counts, more specifically eosinophil numbers, in nasal lavage samples before, 1 hour (1H) and 6 hours (6H) after direct nasal allergen challenge.

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