D1.57 - Antigen-specific IgE antibody levels as negative predictors of oral food challenge with cow's milk in children with cow's milk allergy

Although numerous studies have explored the relationship between food-specific IgE levels and oral food challenge (OFC) outcomes, limited research has focused on the negative predictive value (NPV) for cow's milk. This study aimed to determine milk-specific IgE levels that can predict safe OFC outcomes, particularly in facilities with limited experience in conducting such tests.

We retrospectively analyzed 535 patients aged 0–18 years who underwent OFCs for milk at a single institution between December 2010 and September 2024. Of these, 210 patients with a history of immediate-type reactions to milk ingestion were included in the analysis. Variables such as age, sex, total IgE, and specific IgE levels for milk, casein, β-lactoglobulin, and α-lactalbumin were evaluated alongside OFC outcomes. OFC outcomes were classified as negative if the patient consumed 10 mL or more of the target dose without symptoms or experienced spontaneously resolving symptoms classified as grade 1 or lower based on the Sampson scale. Outcomes were classified as positive if grade 2 or higher symptoms were observed, if the test was discontinued due to symptoms, or if medications were administered.

Among the OFCs, 103 cases were positive, while 107 cases were negative. The cut-off IgE levels with the highest NPV were designated as safety predictive values (SPVs). Overall, the SPVs for milk and casein were 0.63 UA/mL (NPV 92.0%) and 0.60 UA/mL (NPV 94.4%), respectively. SPVs could not be established for β-lactoglobulin and α-lactalbumin due to their lack of correlation with OFC outcomes.

For children with milk allergies, SPVs for milk- and casein-specific IgE levels were identified. These SPVs can serve as predictive markers to support safer milk consumption tests in a variety of clinical settings or at home.