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Data on anaphylaxis cases in pre‐hospital settings is limited. As part of the Cross Canada Anaphylaxis Registry (C‐CARE), we assessed anaphylaxis cases managed by paramedics in Outaouais, Quebec. A software program was developed to prospectively record demographic and clinical characteristics as well as management of cases meeting the definition of the anaphylaxis. Univariate and multivariate logistic regressions were compared to assess factors associated with severity of reactions and epinephrine use. Among 33,788 ambulance calls of which 23,486 required transport, 104 anaphylaxis cases were identified (anaphylaxis rate of 0.31% [95%CI, 0.25%, 0.37%] among all ambulance calls and 0.44% [95%CI, 0.36%, 0.54%] among those requiring transport). The median age was 46.8 years and 41.3% were males. The common triggers included food (32.7% [95%CI, 24.0%, 42.7%]), drugs (24.0% [16.4%, 33.6%]), and venom (17.3% [10.8%, 26.2%]). Among all reactions, 37.5% (95%CI, 28.4%, 47.6%) were severe. Epinephrine was not administered in 35.6% (95%CI, 26.6%, 45.6%) of all cases. Males were more likely to have severe reactions (Odds ratio [OR]: 2.50 [95%CI, 1.03, 6.01]). Venom‐induced reactions and severe anaphylaxis were more likely to be managed with epinephrine (OR: 6.9 [95%CI, 1.3, 35.3] and 4.2 [95%CI, 1.5, 12.0], respectively). This is the first prospective study evaluating anaphylaxis managed by paramedics. Anaphylaxis accounts for a substantial proportion of the cases managed by paramedics in Outaouais, Quebec and exceeds prior reports of the proportion of Quebec emergency room visits attributed to anaphylaxis. Although guidelines recommend prompt use of epinephrine for all cases of anaphylaxis, more than a third of cases did not receive epinephrine. It is crucial to develop educational programs targeting paramedics to promote the use of epinephrine in all cases of anaphylaxis regardless of the specific trigger.

Background: Studies suggest an increase in food allergy prevalence over the last decade, but the contributing factors remain unknown. The aim of this study was to evaluate the association between the most common food allergies and atopic history, sociodemographic characteristics and lifestyle habits. Methods: We conducted a case-control study nested within the SPAACE study (Surveying Prevalence of Food Allergy in All Canadian Environments) - a cross-Canada, random telephone survey. Cases consisted of individuals with probable food allergy (self-report of convincing symptoms and/or physician diagnosis) to milk, egg, peanut, tree nut, shellfish, fish, wheat, soy, or sesame. Controls consisted of nonallergic individuals, matched for age. Cases and controls were queried on personal and family history of atopy, sociodemographic characteristics and lifestyle habits. Multivariate logistic regression was used to evaluate the association between atopy, sociodemographic characteristics and lifestyle habits with probable food allergy. Results: Between September 2010 and September 2011, 480 cases and 4,950 controls completed the questionnaire. For all 9 allergens, factors associated with a higher risk of probable allergy were as follows: (1) personal history of eczema (in the first 2 years of life), asthma or hay fever (odds ratio, OR 2.3, 95% CI 1.6-3.5; OR 2.8, 95% CI 2.2-3.6, and OR 2.3, 95% CI 1.8-3.0, respectively), (2) maternal, paternal or sibling's food allergy (OR 3.7, 95% CI 2.5-5.6; OR 3.0, 95% CI 1.8-5.1, and OR 3.1, 95% CI 2.2-4.2), (3) high household income (top 20%; OR 1.5, 95% CI 1.2-2.0). Males and older individuals were less likely to have food allergy (OR 0.7, 95% CI 0.6-0.9, and OR 0.99, 95% CI 0.99-1.00). Eczema in the first 2 years of life was the strongest risk factor for egg, peanut, tree nut and fish allergy. Conclusions: This is the largest population-based nested case-control study exploring factors associated with food allergies. Our results reveal that, in addition to previously reported factors, eczema in the first 2 years of life is consistently associated with food allergies.

Background: The Cross-Canada Anaphylaxis Registry (C-CARE) assesses the triggers and management of anaphylaxis and identifies predictors of the development of severe allergic reactions and of epinephrine use. Here, we present data from an urban adult tertiary care emergency department (ED) in Montreal, Canada. Methods: Potential anaphylaxis cases were identified using ICD-10 codes related to anaphylaxis or allergic reactions. Putative cases underwent chart review to ensure they met anaphylaxis diagnostic criteria. Demographic, clinical and management data were collected. Multivariate logistic regressions were conducted to assess the effect of demographic characteristics, triggers, and comorbidities on severity and management of reactions. Results: Among 37,730 ED visits, 0.26% (95% CI 0.21, 0.32) fulfilled the definition of anaphylaxis. Food was the suspected trigger in almost 60% of cases. Epinephrine was not administered in almost half of moderate-to-severe cases, and similar numbers of individuals with moderate-to-severe reactions were not prescribed an epinephrine autoinjector. Reaction to shellfish was associated with more severe reactions (OR 13.9; 95% CI 2.2, 89.4). Older individuals and those not receiving steroids were more likely managed without epinephrine (OR 1.04; 95% CI 1.01, 1.07 and OR 2.97; 95% CI 1.05, 8.39, respectively). Conclusions: Anaphylaxis accounted for a substantial number of ED visits in adults, and the most common trigger was food. There is non-adherence to guidelines recommending epinephrine use for all cases of anaphylaxis. We postulate that this may be related to concerns regarding the side effects of epinephrine in adults.

Marissa A. Love, MD, Madison Breeden, BS, Kyle Dack, BA, Alyssa Milner, BA, Andrew C. Rorie, MD, Selina A. Gierer, DO; University of Kansas Medical Center, Kansas City, KS. RATIONALE: We sought to identify geographic disparities and existing barriers to receiving life-saving epinephrine in Kansas schools. METHODS: A survey of school nurses was conducted at the 2015 Kansas School Nurse Association conference. Excel was used to analyze the descriptive data, which was compared to demographics published by the U.S. federal government. RESULTS: In 2009, the Kansas legislature authorized accredited schools to stock emergency epinephrine, pre-dating federal legislation in 2013. Unfortunately, stock epinephrine remains limited to only a few Kansas communities. Our survey revealed significant disparities in implementing stock epinephrine, with 59 of 105 counties reporting. Only 20 counties stocked epinephrine in at least 1 school. When stratifying by household income, 60% of schools that stocked epinephrine were in the top 10% of wealthy counties, whereas 41% that did not were in the bottom 50%. Of schools stocking epinephrine, 35% were in the wealthiest county. Further, 70% of schools with stock epinephrine were associated with the largest urban cores in Kansas. Nurses cited cost, legal liability, having a prescribing physician, lack of staff knowledge or training, and lack of administrator support as reasons why injectable epinephrine was not stocked in their schools. CONCLUSIONS: Our study reveals unequal access to life-saving epinephrine across Kansas, despite state and federal legislation. Further investigation is necessary to resolve this inequality, which disproportionately affects Kansas communities.

Data on anaphylaxis cases in pre-hospital settings is limited. As part of the Cross Canada Anaphylaxis Registry (C-CARE), we assessed anaphylaxis cases managed by paramedics in Outaouais, Quebec. A software program was developed to prospectively record demographic and clinical characteristics as well as management of cases meeting the definition of the anaphylaxis. Univariate and multivariate logistic regressions were compared to assess factors associated with severity of reactions and epinephrine use. Among 33,788 ambulance calls of which 23,486 required transport, 104 anaphylaxis cases were identified (anaphylaxis rate of 0.31% [95%CI, 0.25%, 0.37%] among all ambulance calls and 0.44% [95%CI, 0.36%, 0.54%] among those requiring transport). The median age was 46.8 years and 41.3% were males. The common triggers included food (32.7% [95%CI, 24.0%, 42.7%]), drugs (24.0% [16.4%, 33.6%]), and venom (17.3% [10.8%, 26.2%]). Among all reactions, 37.5% (95%CI, 28.4%, 47.6%) were severe. Epinephrine was not administered in 35.6% (95%CI, 26.6%, 45.6%) of all cases. Males were more likely to have severe reactions (Odds ratio [OR]: 2.50 [95%CI, 1.03, 6.01]). Venom-induced reactions and severe anaphylaxis were more likely to be managed with epinephrine (OR: 6.9 [95%CI, 1.3, 35.3] and 4.2 [95%CI, 1.5, 12.0], respectively). This is the first prospective study evaluating anaphylaxis managed by paramedics. Anaphylaxis accounts for a substantial proportion of the cases managed by paramedics in Outaouais, Quebec and exceeds prior reports of the proportion of Quebec emergency room visits attributed to anaphylaxis. Although guidelines recommend prompt use of epinephrine for all cases of anaphylaxis, more than a third of cases did not receive epinephrine. It is crucial to develop educational programs targeting paramedics to promote the use of epinephrine in all cases of anaphylaxis regardless of the specific trigger.

U E S D A Y 760 Tryptase Levels in Children Presenting with Anaphylaxis to the Montreal Children's Hospital Michelle Halbrich, MD, Ann Elaine Clarke, MD, MSc, Sebastian La Vieille, MD, Harley Eisman, MD, Reza Alizadehfar, MD, Lawrence Joseph, PhD, Judy Morris, MD, Moshe Ben-Shoshan, MD, MSc; McGill University, Montreal, QC, Canada, McGill University Health Centre, Montreal, Canada, Food Directorate, Ottawa, ON, Canada, University de Montreal, Montreal, QC, Canada. RATIONALE: There are little data on the role of tryptase in the diagnosis of anaphylaxis. We aimed to determine if total tryptase levels are elevated (>11.5 ng/mL) at the time of anaphylaxis and to identify factors associated with elevated tryptase levels. METHODS: Children presenting with anaphylaxis to the Montreal Children’s Hospital Emergency Department (ED) between April 2011 and April 2012 were recruited. The treating physician documented symptoms, triggers, and management of the anaphylactic reactions. Total tryptase levels were measured 30-120 minutes following onset of symptoms. Charts of all ED patients were reviewed to identify cases that were missed in prospective recruitment. Multivariate logistic regression was used to examine the association between an elevated tryptase level and age, gender, reaction trigger, reaction severity, and history of atopy. RESULTS: Of 180 anaphylaxis cases (90 of whom were recruited prospectively), 32 children had serum tryptase levels measured. The median age of these 32 children was 6.0 years (IQR 1.2, 11.5), 62.5% [95% CI, 43.8%, 78.3%]weremale, 68.8% (49.9%, 83.3%) identified food as the potential anaphylactic trigger, and 9.4% (2.5%, 26.2%) experienced a severe reaction. Age, gender, anaphylactic trigger, and severity of reaction were comparable between cases with and without tryptase measurements. The mean tryptase level was 6.2 ng/mL (4.5, 8.0). Only 3 patients [9.4% (2.5%, 26.2%)] had elevated levels. Older age (odds ratio (OR) 1.0, 1.01, 1.03) and severe reactions [1.7, (1.3, 2.3)] were associated with higher levels. CONCLUSIONS: Our results do not support the use of total typtase as a diagnostic tool in children with anaphylaxis.

U E S D A Y 787 Anaphylaxis in the Adult Population: Are We Following Current Treatment Guidelines? Yarden Yanishevsky, MD, Ann Elaine Clarke, MD, MSc, Sebastian La Vieille, MD, Scott Delaney, MD, Reza Alizadehfar, MD, Lawrence Joseph, PhD, Judy Morris, MD, Moshe Ben-Shoshan, MD, MSc; Division of Paediatric Allergy and Clinical Immunology, Department of Paediatrics, McGill University Health Center, Montreal, QC, Canada, Division of Clinical Epidemiology, Department of Medicine, McGill University Health Centre, Montreal, QC, Canada, Division of Allergy and Clinical Immunology, Department of Medicine, McGill University Health Centre, Montreal, QC, Canada, Food Directorate, Health Canada, Ottawa, ON, Canada, Department of Emergency Medicine, McGill University Health Center, Montreal, QC, Canada, Departments of Epidemiology and Biostatistics, McGill University, Montreal, Canada, Department of Emergency Medicine , Hopital du Sacr e-Coeur, Montreal, QC, Canada. RATIONALE: Curent guidelines (Simons E et el, J Allergy Clin Immunol. 2011:587-93) recommend that all anaphylactic reactions be treated with epinephrine and all cases of non-drug induced anaphylaxis be prescribed an epinephrine auto-injector (EAI). We aimed to assess anaphylaxis rate in an adult emergency department (ED) and determine if management adheres to current guidelines. METHODS: As part of the Cross-Canada Anaphylaxis REgistry (CCARE), charts of all ED visits to the Montreal General Hospital between March and July 2011 were reviewed to identify anaphylaxis cases. Cases were identified based on ICD 10 coding for either anaphylaxis or allergic reaction and only cases fitting the definition of anaphylaxis were included. RESULTS: Among 12,540 ED visits, 41 anaphylaxis cases [0.3 %, (95% CI 0.2%, 0.5%)] were identified. Median age was 35.2 years (IQR 26.5, 50.9) and 31.7% (95% CI 18.6%, 48.2%) were males. Food was responsible for 46.3% (31.0%, 62.4%) of reactions, drugs for 21.9% (11.1%, 38.0%) and venom for 4.9% (0.9%, 17.8%). In 26.83% (14.6%, 43.2%), the trigger was unidentified. Among all cases 53.7% (37.6%, 69.0%) were moderate (difficulty breathing/stridor/wheezing) or severe (hypoxia/cyanosis/circulatory collapse/incontinence/neurological symptoms). Prior to ED arrival, 13.3% (2.3%, 41.6%) of mild and 16.7% (4.4%, 42.3%) of moderate/severe reactions received epinephrine compared to 27.8% (10.7%, 53.6%) and 22.7% (8.7%, 45.8%) after arrival. In 65% (41.0%, 83.7%) of moderate/severe reactions, no epinephrine was given. In nondrug induced anaphylaxis, EAI were prescribed in only 58.06 % (39.3%, 74.9%). CONCLUSIONS: Given the striking underuse of epinephrine in anaphylaxis management, educational programs are required to better implement current guidelines.

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. 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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. 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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

U E S D A Y 760 Tryptase Levels in Children Presenting with Anaphylaxis to the Montreal Children's Hospital Michelle Halbrich, MD, Ann Elaine Clarke, MD, MSc, Sebastian La Vieille, MD, Harley Eisman, MD, Reza Alizadehfar, MD, Lawrence Joseph, PhD, Judy Morris, MD, Moshe Ben-Shoshan, MD, MSc; McGill University, Montreal, QC, Canada, McGill University Health Centre, Montreal, Canada, Food Directorate, Ottawa, ON, Canada, University de Montreal, Montreal, QC, Canada. RATIONALE: There are little data on the role of tryptase in the diagnosis of anaphylaxis. We aimed to determine if total tryptase levels are elevated (>11.5 ng/mL) at the time of anaphylaxis and to identify factors associated with elevated tryptase levels. METHODS: Children presenting with anaphylaxis to the Montreal Children’s Hospital Emergency Department (ED) between April 2011 and April 2012 were recruited. The treating physician documented symptoms, triggers, and management of the anaphylactic reactions. Total tryptase levels were measured 30-120 minutes following onset of symptoms. Charts of all ED patients were reviewed to identify cases that were missed in prospective recruitment. Multivariate logistic regression was used to examine the association between an elevated tryptase level and age, gender, reaction trigger, reaction severity, and history of atopy. RESULTS: Of 180 anaphylaxis cases (90 of whom were recruited prospectively), 32 children had serum tryptase levels measured. The median age of these 32 children was 6.0 years (IQR 1.2, 11.5), 62.5% [95% CI, 43.8%, 78.3%]weremale, 68.8% (49.9%, 83.3%) identified food as the potential anaphylactic trigger, and 9.4% (2.5%, 26.2%) experienced a severe reaction. Age, gender, anaphylactic trigger, and severity of reaction were comparable between cases with and without tryptase measurements. The mean tryptase level was 6.2 ng/mL (4.5, 8.0). Only 3 patients [9.4% (2.5%, 26.2%)] had elevated levels. Older age (odds ratio (OR) 1.0, 1.01, 1.03) and severe reactions [1.7, (1.3, 2.3)] were associated with higher levels. CONCLUSIONS: Our results do not support the use of total typtase as a diagnostic tool in children with anaphylaxis.