[Comprehensive study of mare's and cow's milk proteins and their hydrolysates in children with allergy to cow's milk proteins].

UNLABELLED: The use of innovative protein ingredients produced by biotechnological methods requires a comprehensive assessment of their allergenic potential for the child's body. The aim of the study was to evaluate the clinical significance and safety profile of hydrolysates of cow's and mare's milk proteins and lactoferrin (LF) for children with cow's milk protein (CMP) allergy. This was based on the investigation of the ability of these products to bind specific IgE, allowing for an assessment of the risks associated with their use, including potential cross-reactivity with mare's milk proteins (MMP) and primary allergenicity.

MATERIAL AND METHODS: LF from bovine colostrum, as well as hydrolysates of CMP and MMP have been used in the study. Protein hydrolysates from a concentrate of whey proteins of cow's milk and skim mare's milk were obtained by enzymolysis using two enzymes: trypsin and protozyme. Unreacted protein and enzyme were removed from the hydrolysates by tangential ultrafiltration through a 10 kDa polyethersulfone membrane, collecting the low-molecular-weight fraction, and subsequent desalination by nanofiltration. The purified and concentrated product was lyophilized using a freeze dryer. Cross-reactivity between protein fractions from different milks was assessed using indirect ELISA. Specific IgE responses to the peptide components of the studied hydrolysates, as well as to LF and bovine serum albumin (BSA), were quantified using enzyme-linked immunosorbent assay. To detect antibodies to native CMP, the commercial AllergoELISA-specific IgE test system was used. Blood serum of 52 children aged 1-6 years (25 boys and 27 girls) with moderate and severe forms of allergic diseases (atopic dermatitis, bronchial asthma, food allergies) with established food allergy to BCM has been used in the research.

RESULTS: The study results showed that cross-reactions between CMP and MMP, and their enzymatic hydrolysates, are expressed insignificantly. The antigenicity reduction coefficient of MMP hydrolysates relative to whey CMP varied from 26.700 to 39.200, and relative to casein fractions of CMP - from 11.000 to 13.800. An immunochemical analysis of blood serum from patients with confirmed sensitization to CMP revealed fundamental differences in IgE reactivity to the studied antigens. A key observation was the virtual absence of significant specific IgE titers to the hydrolyzed MMP. In contrast, sensitization to hydrolyzed CMP was detected in a small but statistically significant proportion of patients (≤10%), demonstrating significantly higher mean antibody levels (p<0.05). LF occupied an intermediate position: its ability to induce IgE synthesis was comparable to CMP hydrolysates but statistically significantly exceeded that of the low-allergenic marker protein, bovine serum albumin (BSA). A critically important result is the confirmation that all four studied antigens (MMP hydrolysate, CMP hydrolysate, LF, BSA) demonstrated repeatedly and reliably (p<0.001) lower values both for the average level of specific IgE and for the frequency of their detection in the diagnostic titer, in comparison with СМР. The comprehensive analysis of the sensitization profile is aimed at establishing the safety degree and determining potential limitations for the use of these products in sensitized patients.

CONCLUSION: The results of the research indicate that MMP hydrolysates are a promising protein component for creating hypoallergenic formulas intended for infants who have a mild degree of sensitization to CMP or a hereditary predisposition to it.