Prediction of Tolerance to Food Allergens by the allergen-specific IgE/Total IgE Ratio

Greetings from San Diego.  As I mentioned last week, I'm currently attending the AAAAI annual meeting, which has been absolutely great so far.  It's been a blast reconnecting with friends and collaborators from all over the country.  In the spirit of the conference, I thought I should share the other presentation that I will be making on Monday, which is a poster entitled "Prediction of Tolerance to Food Allergens by the Allergen-Specific IgE/Total IgE Ratio".  This is an important topic in my opinion because it begins to address a question  that I hear all the time from parents in my clinic: "Will my kid grow out of his food allergy?".   Here's the abstract:

Rationale:  Although allergists typically use allergen-specific Immunoglobulin E (IgE) levels or skin prick test wheal sizes to identify food allergens that may provoke IgE-mediated food-induced allergic reactions, both tests have high rates of false positivity and mislabel patients who are tolerant as allergic to the food allergen.  We sought to examine the accuracy of the ratio of allergen-specific IgE to total IgE (“Ratio”) in predicting the outcome of challenges performed to confirm the development of tolerance.

Methods:  Medical records of food allergy patients participating in an oral food challenge at an allergy outpatient clinic were reviewed for IgE serology and oral food challenge data, which were  analyzed for associations using logistic regressions and Receiver Operator Characteristics curves.

Results:  The Ratio for participants who failed their challenge was higher than the Ratio of those who passed their challenge (failed=1.48% vs. passed=0.49%, n=195).  ROC curves showed the Ratio was significantly more accurate than allergen-specific IgE alone in predicting challenge outcome (Ratio=0.69 vs. sIgE=0.55, P=0.03).  These trends were mostly associated with more persistent food allergens, such as peanut, tree nuts, shellfish, and seeds (failed=2.18% vs. passed=0.41%, n=93) (Ratio=0.81 vs. sIgE=0.54, P<0.01).

Conclusion:  The Ratio is more accurate than allergen-specific IgE alone in predicting outcomes of challenges performed to confirm the development of tolerance to select food allergens, especially to peanut and tree nuts.  The Ratio may be useful in identifying patients most likely to pass an oral food challenge.