Chemoattractant factors in breast milk from allergic and nonallergic mothers

The allergy-preventing effect of breast-feeding remains controversial, poss ibly because of individual variations in the composition of the breast milk . Recently, we showed that allergic mothers had higher concentrations of IL -4 and lower concentrations of ovalbumin-specific IgA in their breast milk than nonallergic mothers. The aim of this study was to investigate the conc entrations of chemokines and cytokines that are chemotactic to cells involv ed in allergic reactions in breast milk from allergic and nonallergic mothe rs. Cytokine and chemokine concentrations were determined with ELISA in col ostrum and mature milk samples from 23 mothers with and 25 mothers without atopic symptoms. IL-8 was detected in all milk samples. RANTES (regulated o n activation, normal T cell expressed and secreted), eotaxin, and IL-16 wer e detected in 50%, 76%, and 48%, respectively, in colostrum and less common ly in mature milk. Macrophage inflammatory protein-1 alpha, however, could not be detected in any of the samples. The concentrations of IL-8 and RANTE S were higher in breast milk from allergic, compared with nonallergic, moth ers. In conclusion, the presence of chemoattractant factors in breast milk may be responsible for the traffic of leukocytes from the maternal circulat ion to the breast milk. The higher concentrations of RANTES and IL-8 in all ergic mothers may partly explain the controversy regarding the protective e ffect of breast-feeding against the development of allergy by stronger chem otaxis and activation of cells involved in allergic diseases, and possibly by elevated IgE production.