NCT05309772

The Clinical Impact of the Basophil Activation Test to Diagnose Food Allergy

Randomised Controlled Multicentre Trial on the Clinical Impact of the Basophil Activation Test and the Mast Cell Activation Test as Food Allergy Biomarkers in Children and Young People

• Status: Unknown
• Phase: N/A
• Study type: Interventional
• Enrollment: 398 (estimated)
• Sponsor: King's College London · Academic / Other
• Sex: All
• Age: 6 Months – 15 Years
• Healthy volunteers: Not accepted

Summary

The BAT Impact study is a prospective multicentre study in the UK using a biomarker-led study design to compare the incidence of adverse events (defined as allergic reactions during oral food challenges) in a randomized-controlled trial. Patients will either follow the standard-of-care (i.e. an oral food challenge in case of equivocal SPT/sIgE) or follow a basophil activation test (BAT)/mast cell activation test (MAT)-based strategy, i.e. patients with a positive BAT or MAT are dispensed of an oral food challenge (OFC) and patients with a negative BAT/MAT undergo an OFC.

Detailed description

Children aged 6 months to 15 years requiring an oral food challenge to one of the study foods (milk, egg, peanut, sesame or cashew nut) will be invited to participate in the study. Eleven centres across the UK will be recruiting participants and perforning clinical procedures, such as skin prick testing and oral food challenges (OFC), as per standard clinical care. Participants will be randomised 4:5 to either have the standard-of-care, i.e. oral food challenge to the suspected food, or take BAT (MAT if BAT inconclusive) into account to decide whether or not OFC will be required: if BAT/MAT is positive, food allergy will be confirmed without doing OFC; if BAT/MAT is negative, participants in the biomarker arm will undergo OFC. The primary outcome is the proportion of positive OFC in the biomarker arm compared with the standard-of-care arm. Secondary outcomes are: number of OFC, quality of life, anxiety and costs associated with the diagnostic work-up.

Conditions

• Food Allergy
• Food Allergy in Infants
• Food Allergy in Children
• Food Allergen Sensitisation
• Milk Allergy
• Egg Allergy
• Nut Allergy

Interventions

Type	Name	Description
DIAGNOSTIC_TEST	Basophil activation test (BAT)	Basophils and mast cells are the key drivers of food allergic reactions and anaphylaxis to foods. The study team have developed new tests that measure the reaction of mast cells and basophils by flow cytometry following stimulation with allergen, the BAT and the MAT: • BAT uses fresh whole blood from patients added to allergen and antibodies in a test tube. The tube containing the allergic cells are then analysed one by one to estimate how many and how much express activation markers on their surface, CD63 and CD203c. MAT uses a human mast cell line (LAD2 cells) which are human mast cells grown in the laboratory to which patients' plasma is added in order to mimic the patients' own mast cells. Sensitised LAD2 cells are then stimulated with allergen or controls and analysed by flow cytometry to assess the expression of the activation marker CD63 on the cell surface, similar to what happens in the BAT. Results of MAT will be considered only in cases of non-responding basophils.
DIAGNOSTIC_TEST	Oral food challenge (OFC)	Consumption of the food suspected of causing an allergic reaction in a medically supervised environment, starting with small amounts and progressively increasing the dose at regular intervals up to a cumulative dose corresponding to an age-appropriate portion of the food.

Timeline

• Start date: 2023-01-13
• Primary completion: 2025-07-01
• Completion: 2025-07-01
• First posted: 2022-04-04
• Last updated: 2023-09-06

Locations

11 sites across 1 country: United Kingdom