Shek LP, Soderstrom L, Ahlstedt S, Beyer K, Sampson HA. J Allergy Clin Immunol. 2004;114:387–391
Purpose of the Study.
To determine if monitoring food-specific IgE levels over time could be used as a predictor for determining when patients develop clinical tolerance.
Eighty-eight patients with hen’s egg allergy and 49 patients with cow’s milk allergy who underwent repeated double-blind placebo-controlled food challenges were included in the study.
Using the Pharmacia CAP System FEIA, specific IgE (sIgE) levels to cow’s milk and hen’s egg were determined retrospectively from stored serum samples obtained at the time of the food challenges. Logistic regression was used to evaluate the relationship between tolerance development and the decrease in sIgE levels over a specific time period between the 2 challenges.
Twenty-eight of the 66 egg-allergic and 16 of the 33 milk-allergic patients lost their allergy over time. The decrease in egg sIgE levels (P = .0014) was significantly related to the probability of developing clinical tolerance, with the duration between challenges having an influence (P = .06). For milk, there was also a significant relationship between the decrease in sIgE levels (P = .0175) and the probability of developing tolerance, but there was no significant contribution with regard to time. Stratification into those <4 years of age and those ≥4 years of age at time of first challenge revealed that the younger age group was more likely to develop clinical tolerance in relation to the rate of decrease in sIgE. The median food sIgE level at diagnosis was significantly lower for the group developing “tolerance” to egg (P < .001), and a similar trend was seen for milk allergy (P = .06). Using these results, a model for predicting the likelihood of developing tolerance in milk and egg allergy based on the decrease in food sIgE over time was constructed.
The rate of decrease in food sIgE levels over time was predictive for the likelihood of developing tolerance in milk and egg allergy. Using the likelihood estimates from this study could aid clinicians in providing prognostic information and in the timing of subsequent food challenges, thereby decreasing the number of premature and unnecessary double-blind placebo-controlled food challenges.
The majority of children with milk and egg allergy eventually develop clinical tolerance; however, there are no reliable tools to predict when and in which patients this may occur. The authors demonstrated a relationship between the degree of decrease in food-specific IgE concentrations over time and the likelihood of developing tolerance. This may be a useful model, allowing clinicians to time food challenges appropriately and provide more prognostic information to patients.