Background Food allergy is one of the most frequent conditions among allergy diseases in early age children, and cow’s milk proteins (CMP) are the most common allergens in these patients. allergy. Nowadays distinct predictors of the development of tolerance to CMP have not yet been defined. So, definition of the immunophenotypes of CMP allergy seems to be helpful in practice and, accordingly, will significantly facilitate the follow-up of these patients.

Objective To determine immunophenotypes of CMP allergy and assess their role in predicting the development of tolerance to CMP.

patients and methods. We provided the prospective observational study and observed 153 children with CMP allergy aged 1–18 month. Blood samples were taken to determine sIgE (UniCAP method) and sIgG4 (ELISA) to CMP and its fractions twice – before elimination diet and after 6–12 months of elimination diet and oral challenge of CMP.

Results Oral food challenge procedure with CMP was performed after 6–12 months of elimination diet. As a result, 50.3% children became tolerant to CMP, of which 42 developed tolerance by the end of the first year (54.5% of all children who developed tolerance), and 35 by the end of the 2nd year (45.5% of all who developed tolerance). During assessment of immunological markers, taken, before elimitation diet, we defined 4 immunophenotypes., Thus, 19.2% of patients with ‘sIgE≤0,7 kUA/L and sIgG4 0–2+’ immunophenotype, and none of the patients with ‘sIgE>0,7 kUA/L and sIgG4 0–2+’ immunophenotype became tolerant after after 6–12 of the elimination diet (p<0,05). So, these results seem to provide unfavourable evidence regarding the development of tolerance to CMP. In contrast, tolerance to CMP developed in 97.9% of patients with ‘sIgE≤0,7 kUA/L and sIgG4 3+’ immunophenotype, and in 90.1% of patients with ‘sIgE>0,7 kUA/L and sIgG4 3+’ immunophenotype. These results indicate a high probability of development of tolerance to CMP after 6 months of elimination diet in children with these immunophenotypes.

Conclusion Different sIgE/sIgG4 immunophenotypes of CMP allergy can be successfully used as new diagnostic tool for predicting the development of tolerance to CMP in early age children.