Assessment of the immunoglobulin E-mediated immune response to milk-specific proteins in allergic patients using microarrays

Background Cow's milk allergy (CMA) is one of the most widespread human allergies, especially in young children. Although CMA is intensively studied, little is known about the recognition patterns of milk allergens in allergic patients, and the determination these patterns is a prerequisite for the development of efficient diagnostic and prognostic tools. Several factors present difficulties for such a determination, because (i) milk contains a large number of potential allergens; (ii) the majority of these allergens consist of complex suspensions rather than solutions; (iii) the major allergens, such as caseins, cannot be highly purified in large amounts; and (iv) most of the time, very small amount of young patients' sera are readily available. Methods To overcome these difficulties, we developed a sensitive microarray assay that, in combination with near-infrared fluorescence detection, was used to study the immune response to milk and purified native milk proteins. Results This new assay allowed us to assess the binding ability of IgE to milk allergens from a large number of young patients using reduced amounts of clinical material. The data show that bovine lactoferrin can be classed as a strong milk allergen. We confirmed that bovine caseins are the main allergens in milk and that alpha(S1)-casein is more allergenic than alpha(S2)-, beta- and kappa-caseins, which were recognized with almost a similar frequency by the sera of patients. Conclusion Microarray methods, in combination with near-infrared fluorescence detection, can be useful for the in vitro diagnosis of food allergies.