Individual cow's milk allergens as prognostic markers for tolerance development?

BACKGROUND: Cow's milk allergy (CMA) is one of the most common causes of food allergy in the first years of life. Fortunately, the majority of children with CMA develop clinical tolerance with time. However, no good individual markers exist to predict whether this will occur. Therefore, a prognosis to identify children with persistent CMA at diagnosis would be helpful. OBJECTIVE: In this study, we sought to assess whether measurement of IgE to individual allergens of cow's milk (CM) would separate patients with persistent CMA from those who became clinically tolerant to CM over time. METHODS: A total of 52 patients ranging from 3 months to 114 months of age with proven CMA by DBPCFC were followed over time. From these 52 patients, 32 (61.5%) patients became tolerant in the analysed time period. All patients were rechallenged at least once, some were rechallenged two or three times. Serum was analysed prior to each challenge for specific IgE, IgG and IgG4 binding to crude CM protein as well as to individual allergens of CM. RESULTS: The individual likelihood of outgrowing CMA significantly correlates with a low level of CM-specific IgE as well as a low level of specific IgE to α-lactalbumin, ß-lactoglobulin (Bos d5.0102), κ-casein and α(s1) -casein. No significant correlation was found for IgE levels to total casein, lactoferrin, ß-casein and ß-lactoglobulin (Bos d5.0101) as well as IgG and IgG4 levels to α-lactalbumin, ß-lactoglobulin and total casein. CONCLUSIONS: CM-specific IgE is a good prognostic marker for persistence of CMA. In addition, component-resolved diagnostic showed similar results. However, in our view, the rising laboratory costs do not justify a measurement on a daily basis. Additional determination of specific IgG or IgG4 levels was not useful in predicting tolerance development in our study population.