Clinical characteristics of oral tolerance induction of non-IgE mediated food allergy using IFN-gamma

Background: Food allergies are classified as IgE-mediated (IFA)and non-IgE-mediated (NFA). Late eczematous reactions of the skin were found to be one of typical and diagnostic symptoms of NFA. Clinically, oral immunotherapy for food allergy has been tried to induce oral tolerance.

Objective: Recently, oral immunotherapy for food allergy has been successful in NFA using subcutaneous IFN-gamma injection. We are to characterize the clinical findings of NFA and the induction of the oral tolerance to food allergen in NFA after oral immunotherapy using IFN-gamma.

Methods: Non-IgE-mediated food allergies were diagnosed by food challenge, skin prick test and food-specific IgE. Total 77 NFA patients with atopic dermatitis that is characterized by late eczematous skin reaction were selected in this study. 37 subjets were treated with a relevant OIT protocol for NFA. As a control group 10 subjets received only IFN-gamma without allergenic food. 10 subjets receive only food without IFN-gamma, and 20 subjets with NFA did not receive treatment. Patients were evaluated clinically after treatment using subcutaneous IFN-gamma injection.

Results:  All patients became successfully tolerized to previously offensive foods (changes in clinical severity scores by food challenge from 15.9 ± 3.6 to 1.8 ± 1.0 points, p <0.001), whereas none of the other controls acquired tolerance. By food challenge, the changes in clinical severity scores were from 17.4 ± 4.4 to 15.5 ± 5.0 points (p >0.05) in a group of only IFN-gamma treatment without food, from 14.6 ± 3.6 to 14.1 ± 3.0 points (p>0.05) in a group of only food challenge without IFN-gamma treatment, and from 15.9 ± 3.7 to 15.4 ± 4.3 points (p >0.05) in a untreated group with neither IFN-gamma nor food.

Conclusions: Non-IgE-mediated food allergy can be successfully treated by relevant oral immunotherapy using IFN-gamma. IFN-gammaƒnseemed to be necessary for the tolerance induction.