Detection of IgA antibodies to cat, beta-lactoglobulin, and ovalbumin allergens in human milk

Background: The relationship between the development of allergy during infa ncy and breast-feeding remains controversial. This controversy may be due t o individual variations in the composition of human milk. Antibodies to foo d antigene to which the mother is commonly exposed are present in the milk, but their relationship to allergy is still unknown. IgA antibodies to inha lant allergens have not been previously detected. Objective: Our purpose was to analyze secretory IgA antibody levels to cat, beta-lactoglobulin, and ovalbumin allergens in colostrum and mature milk i n relation to maternal allergy, Methods: Colostrum and samples of mature milk were obtained after 1 and 3 m onths of lactation from 53 nursing mothers (17 allergic and 36 nonallergic mothers) and were analyzed for total secretory IgA levels by ELISA and secr etory IgA antibodies to cat, beta-lactoglobuIin, and ovalbumin by an enzyme -amplified ELISA, The specificity of the assays was confirmed by inhibition experiments. Results: Secretory IgA to cat, beta-lactoglobulin, and ovalbumin allergens were detected in colostrum as well as mature milk. The levels of secretory IgA to ovalbumin were lower in colostrum from allergic mothers with P = .01 6, whereas the levels to beta-lactoglobulin and cat were similar in the 2 g roups. IgA antibodies to ovalbumin were detected in 94% of the colostrum sa mples from allergic and in all samples from nonallergic mothers, in 82% and 96%, respectively at 1 month, and 53% and 65% at 3 months. Fewer samples h ad detectable secretory IgA antibodies to beta-lactoglobulin than to ovalbu min and cat, and only 33% and 10% of the samples from the allergic and nona llergic mothers, respectively, remained positive at 3 months. All the aller gic mothers had detectable IgA to cat in colostrum, whereas 83% and 73% of the samples were positive at 1 and 3 months, The corresponding numbers mere 93%, 81% and 81% in the nonallergic mothers (not significant). Conclusion: Even a low level of exposure of the mucosa (eg, by inhalant all ergens) can induce antibody secretion into the milk, both in allergic and n onallergic mothers.