title: Peanut Allergen Threshold Study (PATS): Novel single-dose oral food challenge study to validate eliciting doses in children with peanut allergy.
abstract: BACKGROUND
  Eliciting doses (EDs) of allergenic foods can be defined by the distribution of threshold doses for subjects within a specific population. The ED05is the dose that elicits a reaction in 5% of allergic subjects. The predicted ED05for peanut is 1.5 mg of peanut protein (6 mg of whole peanut).
  
  
  OBJECTIVE
  We sought to validate the predicted peanut ED05(1.5 mg) with a novel single-dose challenge.
  
  
  METHODS
  Consecutive eligible children with peanut allergy in 3 centers were prospectively invited to participate, irrespective of previous reaction severity. Predetermined criteria for objective reactions were used to identify ED05single-dose reactors.
  
  
  RESULTS
  Five hundred eighteen children (mean age, 6.8 years) were eligible. No significant demographic or clinical differences were identified between 381 (74%) participants and 137 (26%) nonparticipants or between subjects recruited at each center. Three hundred seventy-eight children (206 male) completed the study. Almost half the group reported ignoring precautionary allergen labeling. Two hundred forty-five (65%) children experienced no reaction to the single dose of peanut. Sixty-seven (18%) children reported a subjective reaction without objective findings. Fifty-eight (15%) children experienced signs of a mild and transient nature that did not meet the predetermined criteria. Only 8 (2.1%; 95% CI, 0.6%-3.4%) subjects met the predetermined criteria for an objective and likely related event. No child experienced more than a mild reaction, 4 of the 8 received oral antihistamines only, and none received epinephrine. Food allergy-related quality of life improved from baseline to 1 month after challenge regardless of outcome (η2= 0.2, P < .0001). Peanut skin prick test responses and peanut- and Ara h 2-specific IgE levels were not associated with objective reactivity to peanut ED05.
  
  
  CONCLUSIONS
  A single administration of 1.5 mg of peanut protein elicited objective reactions in fewer than the predicted 5% of patients with peanut allergy. The novel single-dose oral food challenge appears clinically safe and patient acceptable, regardless of the outcome. It identifies the most highly dose-sensitive population with food allergy not otherwise identifiable by using routinely available peanut skin prick test responses or specific IgE levels, but this single-dose approach has not yet been validated for risk assessment of individual patients.
authors.affiliation: Paediatrics and Child Health, University College, Cork, Ireland. Electronic address: J.Hourihane@ucc.ie.
authors.forename: Jonathan O'B
authors.initials: JO
authors.lastname: Hourihane
authors.affiliation: Murdoch Childrens Research Institute, Department of Paediatrics, University of Melbourne, Melbourne, Australia; Department of Allergy and Immunology, Royal Children's Hospital, Melbourne, Australia.
authors.forename: Katrina J
authors.initials: KJ
authors.lastname: Allen
authors.affiliation: Food Allergy Centre and Centre for Immunology and Inflammatory Disease, and Massachusetts General Hospital/Harvard Medical School, Boston, Mass.
authors.forename: Wayne G
authors.initials: WG
authors.lastname: Shreffler
authors.affiliation: Paediatrics and Child Health, University College, Cork, Ireland; School of Applied Psychology, University College, Cork, Ireland.
authors.forename: Gillian
authors.initials: G
authors.lastname: Dunngalvin
authors.affiliation: Food Allergy Research and Resource Program, University of Nebraska, Lincoln, Neb.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Nordlee
authors.affiliation: Murdoch Childrens Research Institute, Department of Paediatrics, University of Melbourne, Melbourne, Australia; Centre for Chronic Disease, College of Health and Biomedicine, Victoria University, Melbourne, Australia.
authors.forename: Giovanni A
authors.initials: GA
authors.lastname: Zurzolo
authors.affiliation: Paediatrics and Child Health, University College, Cork, Ireland; School of Applied Psychology, University College, Cork, Ireland.
authors.forename: Audrey
authors.initials: A
authors.lastname: Dunngalvin
authors.affiliation: Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Australia.
authors.forename: Lyle C
authors.initials: LC
authors.lastname: Gurrin
authors.affiliation: Food Allergy Research and Resource Program, University of Nebraska, Lincoln, Neb.
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Baumert
authors.affiliation: Food Allergy Research and Resource Program, University of Nebraska, Lincoln, Neb.
authors.forename: Steve L
authors.initials: SL
authors.lastname: Taylor
mesh_terms: D000293:Adolescent; D000485:Allergens / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology; D052179:Antigens, Plant / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology; D010367:Arachis / Q000009:adverse effects / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007223:Infant; D008297:Male; D008954:Models, Biological; D021183:Peanut Hypersensitivity / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D010940:Plant Proteins / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology; D011788:Quality of Life; D015203:Reproducibility of Results; D012882:Skin Tests
chemical_list: D000485:Allergens; D052179:Antigens, Plant; D010940:Plant Proteins; D007073:Immunoglobulin E
keywords: Eliciting dose; Peanut Allergen Threshold Study; Voluntary Incidental Trace Allergen Labelling; food allergy related quality of life questionnaire; oral food challenges; peanut thresholds; single dose