Multi-Food Oral Immunotherapy for Peanut and Tree Nuts

This study aims to evaluate the efficacy and safety of multi-food oral immunotherapy (multi-OIT) using peanut and tree nuts proteins in children with confirmed food allergy to at least two allergens. Participants will be randomized in a 2:1 ratio to receive either multi-OIT or standard management consisting of an elimination diet. The primary objective is to evaluate immunotherapy efficacy defined as achieving tolerance to a cumulative dose of 4444 mg of protein during an oral food challenge (OFC-2) for at least one allergen that elicited a reaction during baseline challenge (OFC-1), compared with the control group. Secondary outcomes include the proportion of participants tolerating multiple allergens at the target cumulative dose; the incidence, type, and severity of adverse events classified according to the World Allergy Organization (WAO) grading system; changes in immunological parameters, including allergen-specific IgE and IgG4 levels; changes in skin prick test responses; changes in the quality of life of patients and their families.

Inclusion Criteria: * Age 1-12 years; * Confirmed allergy to at least two allergens included in the protocol, i.e., peanut and/or tree nuts: cashew, walnut, hazelnut, and almond; * Positive skin prick test (SPT) (wheal diameter ≥ 3 mm) and/or specific IgE (sIgE) level \> 0.35 kUA/L for at least two of the analyzed allergens; * Positive OFC-1 (oral food challenge) of grade I-IV according to the WAO classification for at least two allergens, with a positive reaction occurring after administration of a dose ≥ 3 mg and ≤ 3000 mg of allergen protein; * Participants may be enrolled based on the abbreviated procedure as outlined in the study description; * Written informed consent obtained from a legal guardian, and, where applicable, assent from the child in accordance with their age and level of maturity; * Good prognosis for compliance and cooperation of the patient and their caregivers. Exclusion Criteria: * Allergic reaction at the lowest challenge dose of 1 mg of allergen protein for any allergen, or no allergic reaction after administration of the maximum dose of 3000 mg of allergen protein for at least four of the analyzed allergens; * History of anaphylaxis with a grade V reaction according to the WAO classification, either during an oral food challenge or in the patient's medical history; * Severe asthma; * Poorly controlled asthma according to GINA 2025 (lack of symptom control and/or ≥2 exacerbations requiring systemic glucocorticoids or ≥1 exacerbation requiring hospitalization within the last 12 months), or in children able to perform spirometry: FEV1 \< -1.64 Z-score and/or FEV1/FVC \< -1.64 Z-score; * Eosinophilic gastrointestinal disease; * Other chronic diseases requiring ongoing treatment which, in the investigator's opinion, may increase the risk associated with study participation or interfere with the interpretation of results, including severe cardiac disease, epilepsy, metabolic disorders, or diabetes; * Previous immunotherapy with food allergens; * Concurrent immunotherapy with aeroallergens; * Treatment with biologic agents, beta-blockers, ACE inhibitors, or calcium channel blockers; * Oral corticosteroid therapy meeting any of the following criteria: daily treatment for \>1 month within the last 12 months; at least two courses lasting ≥7 days within the last 12 months; one course lasting ≥7 days within the last 3 months; * Lack of consent to participate in the study or insufficient cooperation of the patient and/or caregivers. In such cases, patients will receive standard medical care, including allergen avoidance and provision of emergency medication. Well-controlled asthma, allergic rhinitis, and atopic dermatitis are not exclusion criteria.