Specific oral tolerance induction with food in children: transient or persistent effect on food allergy?

The standard treatment of food allergy is elimination of the incriminated food from the diet. Specific oral tolerance induction (SOTI) seems to be a promising approach for a causal treatment; however, it is unclear whether the tolerance achieved is transient or persistent. We report on a subset of three patients of a larger ongoing study who were treated successfully with SOTI treatment, but experienced a secondary loss of tolerance after a period of allergen avoidance.

The patients suffered from IgE-mediated allergy either to cow's milk (CM) (patient A) or hen's egg (HE) (patients B and C), confirmed by double-blind, placebo-controlled food challenge (DBPCFC). SOTI treatment was performed at home on a daily basis until tolerance to a maximum of 250 ml CM or 4.5 g lyophilized HE protein was achieved. The daily maintenance dose was 100 ml CM or 2.5 g HE protein.

Patients A, B and C reached tolerance to the maximum dose after 37, 41 and 52 weeks, respectively. According to the protocol, patients A and B performed a strict secondary elimination diet for 2 months prior to a follow-up DBPCFC after a maintenance phase of 27 and 39 weeks, respectively. Patient C discontinued treatment for 2 days after 4 weeks on the maintenance dose. Despite previous tolerance, on re-exposure to the allergen all patients experienced moderate systemic allergic reactions.

We conclude that SOTI can induce transient tolerance in food allergy, but does not necessarily lead to its permanent abrogation. Regular allergen intake seems necessary to maintain the established tolerance.