Allergenicity of mare's milk in children with cow's milk allergy

Background: Cow's milk allergy is a common disease of infancy and early chi ldhood. If the baby is not breast-fed, a substitute for cow's milk formula is necessary. Objective: The aim of this study was to investigate, in vitro and in vivo, the allergenicity of mare's milk in a population of selected children with severe IgE-mediated cow's milk allergy. Methods: Twenty-five children (17 male and 8 female) aged 19 to 72 months ( median age 34 months) with IgE-mediated con's milk allergy were selected fo r this study. All the children underwent skin prick tests with cow's milk a nd mare's milk and double-blind placebo-controlled oral food challenge (DBP -COFC) with fresh cow's milk, fresh mare's milk, and, as placebo, a soy for mula (Isomil, Abbott. Campoverde, Italy). We performed immunoblotting of co w's and mare's milk developed with IgE from allergic children. Results: All the children showed strong positive skin test responses to cow 's milk (4+); 2 children had positive skin test responses to mare's milk (2 +). All children had positive DBP-COFCs to cow's milk; one child had a posi tive DBP-COFC to mare's milk. No children reacted to the placebo (lsomil). In the cow's milk, some proteins are able to strongly react with human IgE; when the sera are tested with mare's milk, the bands corresponding to the same proteins are recognized by a lower percentage of sera. Conclusion: These data suggest that mare's milk can be regarded as a good s ubstitute of cow's milk in most children with severe IgE-mediated cow's mil k allergy. It would be prudent, however, to confirm its tolerability by a s upervised titrated oral challenge test.