Basophil Activation Test to Diagnose Food Allergy (BAT2)

The BAT II Study is a cross-sectional diagnostic study in which children with suspected IgE-mediated allergy to foods (namely cow's milk, egg, sesame and cashew), as defined by a history of an immediate-type allergic reaction to a food or no history of food consumption or the presence of food-specific IgE as documented by skin prick test or serum specific IgE, will undergo a diagnostic work-up to confirm or refute the diagnosis of IgE-mediated food allergy. Participants will be prospectively recruited from specialised Paediatric Allergy clinics in London and will undergo skin prick testing (SPT), specific IgE testing to allergen extracts and allergen components, basophil activation test (BAT) and oral food challenge. The diagnostic accuracy of the BAT and of other allergy tests will be assessed against the clinical gold-standard.

Study Overview

• Status: Unknown
• Conditions: Egg Allergy; Food Allergy; Food Allergy in Children; Milk Allergy; Food Allergy in Infants; Nut Allergy; Food Allergen Sensitisation
• Intervention / Treatment: Diagnostic test: Oral food challenge

• Study Type: Observational
• Enrollment (Anticipated): 600

Contacts and Locations

Study Locations

• United Kingdom
  • London, United Kingdom, SE17EH
    • Recruiting
    • Pediatric Allergy Clinical Research Facility, Evelina Children's Hospital
    • Contact: Monica Basting; Email: monica.basting@kcl.ac.uk
    • Principal Investigator: Alexandra Santos, MD PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 10 months to 14 years (Child)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Probability Sample

Study Population

Children seen in specialized Pediatric Allergy clinics with suspected allergy to one of the foods studied, namely milk, egg, sesame and nuts.

Description

Inclusion Criteria:

1. Children ≥6 months and <16 years old;

2. Suspected IgE-mediated food allergy defined by:

   • History of an immediate-type allergic reaction to a specific food or
   • No history of consumption of the specific food or
   • IgE sensitisation documented by skin prick test (≥1 mm) or serum specific IgE (≥0.10 KU/L);
3. Avoidance of the specific food for at least 2 days prior to blood collection for BAT and specific IgE and prior to the challenge;
4. Informed consent obtained from parent or guardian and assent obtained from the child.

Exclusion Criteria:

1. Clinically significant chronic illness other than atopic diseases;
2. Previous history of severe life-threatening reaction to the suspected food with documented decrease in oxygen saturation (<90%), hypotension (≥20% reduction in systolic blood pressure) and/or admission to intensive care;
3. Unwillingness to comply with study procedures, namely to undergo a diagnostic food challenge;

4. Contra-indication for diagnostic food challenge, namely:

   • Uncontrolled atopic diseases (e.g. eczema, asthma, rhinitis);
   • Chronic medical conditions that pose significant risk in the event of anaphylaxis or treatment of anaphylaxis (e.g. cardiac disease, severe lung disease, pregnancy, mastocytosis);
   • Inability to discontinue medications that might interfere with assessment or safety (e.g. antihistamines, β-agonists, β-blockers, NSAIDs, ACE inhibitor, antacids);
   • Recent (within 7-14 days) treatment with systemic steroids or prolonged high-dose systemic steroids or immunosuppressants;
5. Undergoing treatment with omalizumab, food allergen immunotherapy or other systemic immunomodulatory treatment;
6. Inability to stop anti-histamines prior to SPT.

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Prospective

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Food allergic; Patients with a positive oral challenge to the food being studied.	Diagnostic test: Oral food challenge; Patients with suspected food allergy will undergo clinical and dietary assessments and oral food challenge. Different allergy tests will be performed, including skin prick test, specific IgE test and basophil activation test, and its diagnostic utility will be determined against the clinical gold-standard.; Other Names: Basophil activation test; Skin prick test; Specific IgE test
Non food allergic; Patients with a negative oral challenge to the food being studied.	Diagnostic test: Oral food challenge; Patients with suspected food allergy will undergo clinical and dietary assessments and oral food challenge. Different allergy tests will be performed, including skin prick test, specific IgE test and basophil activation test, and its diagnostic utility will be determined against the clinical gold-standard.; Other Names: Basophil activation test; Skin prick test; Specific IgE test

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Diagnostic accuracy of the basophil activation test (for each individual food allergy)	Accuracy of %CD63+ basophils	3 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Diagnostic accuracy of SPT, specific IgE to extracts and to single allergens	Accuracy of weal diameter or level of IgE	3 years
Association between BAT and severity of symptoms during challenges	Correlation between %CD63+ basophils and severity grade	3 years
Association between BAT and threshold of reactivity during challenges	Correlation between CD-sens and cumulative threshold dose	3 years

Collaborators and Investigators

• Sponsor: King's College London
• Collaborators: Guy's and St Thomas' NHS Foundation Trust
• Investigators: Principal Investigator: Alexandra Santos, MD PhD, King's College London

Study record dates

Study Major Dates

• Study Start (Actual): January 30, 2018
• Primary Completion (Anticipated): July 31, 2021
• Study Completion (Anticipated): July 31, 2021

Study Registration Dates

• First Submitted: July 7, 2017
• First Submitted That Met QC Criteria: October 9, 2017
• First Posted (Actual): October 13, 2017

Study Record Updates

• Last Update Posted (Actual): September 2, 2020
• Last Update Submitted That Met QC Criteria: September 1, 2020
• Last Verified: September 1, 2020

More Information

Terms related to this study

• Keywords: Diagnosis; Egg allergy; Basophil activation test; Food allergy; Skin prick test; Milk allergy; Nut allergy; Specific IgE
• Additional Relevant MeSH Terms: Immune System Diseases; Hypersensitivity, Immediate; Nut and Peanut Hypersensitivity; Hypersensitivity; Milk Hypersensitivity; Egg Hypersensitivity; Food Hypersensitivity; Nut Hypersensitivity
• Other Study ID Numbers: IRAS 197886

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No