Efficacy of cashew nut protein immunotherapy: protocol for a single-centre randomised controlled trial in a Polish paediatric population.

Abstract

Introduction: The prevalence of food allergies, particularly IgE-mediated allergies, is rising in developed countries, with cashew nut allergy emerging as a significant public health concern due to its potential for severe anaphylaxis and frequent association with atopic disorders. Cashew nuts are among the most common allergens in Europe and Australia, often involving cosensitisation with pistachios, hazelnuts and other allergens. Diagnosis relies on clinical history, measurement of specific IgE (sIgE) levels, skin prick tests (SPT) and oral food challenges (OFCs). Current management strategies focus on allergen avoidance and emergency interventions, whereas oral immunotherapy (OIT) represents a promising approach to desensitisation. Recent studies, including the NUT CRACKER trial, have reported high desensitisation rates with cashew OIT, although these are associated with a risk of adverse events. This study introduces a novel randomised controlled trial aimed at evaluating the efficacy and safety of cashew immunotherapy in children.

Methods and analysis: This randomised, open-label, parallel-group trial, with a 2:1 allocation ratio, will be conducted at the Department of Paediatric Pneumology and Allergology, Medical University of Warsaw, Poland. Thirty-nine children, aged 4-17 years, with confirmed IgE-mediated cashew allergy via open OFC will be enrolled. Participants in the experimental group will undergo OIT, which involves gradually increasing doses of cashew protein up to a maintenance dose of 1200 mg. The duration of OIT will range from 12 to 60 weeks, depending on individual baseline tolerance. The control group will receive standard management, including strict cashew avoidance and emergency response strategies to accidental exposure, for 1 year.The primary endpoint is to determine the proportion of participants tolerating a 4043 mg dose of cashew protein at the study's end in the OIT group compared with the control group. Secondary outcomes include evaluating the safety profile of OIT, assessing changes in laboratory markers such as sIgE and IgG4 levels for cashew and the major cashew allergen Ana o 3, analysing basophil activation test responses and measuring changes in SPT wheal diameter at baseline and study completion.

Ethics and dissemination: The study has been approved by the Ethics Committee of the Medical University of Warsaw (approval number: KB/267/2023). Study findings will be published in peer-reviewed journals and presented at international conferences.

Trial registration number: NCT06328504.