Bovine milk allergenicity.

OBJECTIVE: To provide updated data on the characteristics (eg, structure, function, stability) of the main milk proteins identified as allergens and on the characterization of their epitopes. DATA SOURCES: Basic literature and the most relevant original recent publications on clinical and epidemiologic aspects of milk allergy and the biochemistry and immunochemistry of milk proteins. STUDY SELECTION: The expert opinion of the author was used to select the relevant data for the review.
RESULTS: Most milk proteins, even proteins present at low concentrations, are potential allergens. Epitopes on milk proteins are both conformational and linear epitopes, widely spread throughout the protein molecules. They may be short fragments, located in hydrophobic parts of the molecule, that comprise highly conserved sequences responsible for IgE cross-reactivity with corresponding milk proteins of other mammals, including humans. Those sequential epitopes have also been proposed as good markers of persistent allergy to milk proteins and may be of particular clinical significance.
CONCLUSIONS: No specific structure or function is associated with allergenicity of milk proteins. Due to the great variability and heterogeneity of the human IgE response, no single allergen or particular structure can account for a major part of milk allergenicity. Furthermore, the available evidence is not sufficient to establish an intake threshold below which allergic reactions are not triggered or to predict reliably the effect of food processing on allergenic potential of milk proteins.