Phenotypical Characterization of Peanut Allergic Children

Study Overview
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Brief Summary
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Peanut allergy (PA) has been well studied and its prevalence was estimated up to 1.3% in Europe. Tree nut (TN) allergy and PA are clinically similar and often coexist, TN allergy prevalence ranged from 0.05 to 4.9 %. TN allergy is longlasting and nearly all TN have been associated with fatal allergic reactions . Other legumes or TN also contain seed storage protein orthologs of the globulins (Ara h1, Ara h 3) and 2S albumins (Ara h 2) of peanut, susceptible to provoke allergic reactions, but cross-reactivity to TN and other legumes in PA patients could also appear through primarily sensitization. These possible IgE-binding cross-reactions bring to recommend the avoidance of TN and other legumes which have never been eaten in PA children. In this context, diagnosis work-up of relevant cross-allergy versus asymptomatic cross-sensitization will impact directly children's health-related quality of life (HRQL). When physicians suspect food allergy, many parameters have to be considered, such as clinical background, clinical history, type of symptoms related to the suspected food and cross-allergy to other foods. Then, to objectively confirm a food allergy and to assess its severity (related to the threshold reactive dose and symptoms), an oral food challenge (OFC) is demanded, and double-blind placebo-controlled food challenge (DBPCFC) is considered as the gold standard. Although OFC are more and more available in the diagnosis of PA, the assessment of cross-allergy to every single allergenic TN and legumes requires full allergy work-up and often many years of follow-up. Few studies investigated cross-allergy to TN and other legume, with rates of cross-allergy to TN between 28% and 50%. However, targeting patients with severe or cross-allergic phenotypes would greatly assist the allergist in management and follow-up of PA patients (i.e., planning OFC to cross-reactive food). Our main objective is to identify different disease phenotypes of PA children with cluster analysis. This statistical approach has never been performed to identify cross-allergic phenotypes. We also will describe cross-allergy in PA and will identify possible risk factors for cross-allergy to TN and other legumes in PA children.

Official Title
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Phenotypical Characterization of Peanut Allergic Children With Differences in Cross-allergy to Tree Nuts and Other Legumes

Conditions
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Nut Hypersensitivity, Child, Legumes Allergy, Tree Nut Allergy, Allergy Cross Reaction

Intervention / Treatment
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* Other: Cross reaction detection


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Child evaluated at the allergy Unit of Saint Vincent Hospital of Lille (France) from March 2004 to May 2016 Peanut allergy proven with a double-blind placebo-controlled food challenge Exclusion Criteria: Patients who had incomplete evaluation for major peanut component at the time of their double-blind placebo-controlled food challenge to peanut. All patients refusing Oral Food Challenge.
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Peanut allergic children<br> | Other: Cross reaction detection<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Double-blind placebo-controlled food challenge Test for determination of type of allergic reaction | After the test (DBPCFC) the type of allergic reaction will be registered: asthma and allergic rhinitis (AR) | at inclusion | 
| Double-blind placebo-controlled food challenge Test for determination of threshold reactive dose |  | at inclusion | 
| Measure of specific IgEs for the peanut component Ara h 1, Ara h 2, Ara h 3 |  | at inclusion | 
| Oral food challenge test for diagnosis of tree nuts and/or other legumes allergies |  | through the study completion |