Cytokines 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 . The aim of this study was to investigate the concentrations of cytokines involved in allergic reactions and IgA antibody production in breast milk f rom allergic and nonallergic mothers. The cytokine concentrations were dete rmined in colostrum and 1-mo milk samples from 24 mothers with, and 25 moth ers without, atopic symptoms, using commercial ELISA kits. The immunosuppre ssive cytokine transforming growth factor-beta was predominant and was dete ctable in all milk samples. IL-6 was detected in the majority of colostral and mature milk samples, whereas the other cytokines were less commonly det ected. The concentrations of IL-6, IL-10, and transforming growth factor-be ta, which are all involved in IgA synthesis, correlated with each other and with total IgA concentrations in colostrum. The concentrations of IL-4 wer e higher in colostrum from allergic than nonallergic mothers, and similar t rends were seen for IL-5 and IL-13. In conclusion, transforming growth fact or-beta and IL-6 were the predominant cytokines in human milk. The correlat ion between the concentrations of cytokines involved in IgA synthesis, i.e. IL-10, IL-6, and transforming growth factor-beta, may explain the stimulat ory effect on IgA production in breast-fed babies. Varying concentrations o f IL-4, IL-5, and IL-13 may explain some of the controversy regarding the p ossible allergy-preventive effect of breast-feeding.