Transforming growth factor-beta in breast milk: A potential regulator of atopic disease at an early age

Background: According to data from animal and in vitro studies, transformin g growth factor-beta (TGF-beta) has a crucial effect on 2 essential parts o f the mucosal immune system: IgA production and oral tolerance induction. Objective: We sought to ascertain whether TGF-beta in breast milli is assoc iated with specific IgA production and atopic disease in human subjects. Methods: Forty-seven infants with several atopic family members were follow ed during their first year of life. The concentrations of TGF-beta 1 and TG F-beta 2 in maternal colostrum, mature milk, and the infants' sera were det ermined. The enzyme-linked immunospot assay was used to assess the infants' specific IgA production in response to beta-lactoglobulin, casein, gliadin , and ovalbumin, Results: At 12 months, atopic dermatitis was confirmed in 29 of 47 infants; in 11, atopic disease had begun during exclusive breast-feeding (preweanin g onset), whereas in 18 the disease manifested itself after weaning (postwe aning onset), The concentrations of both TGF-beta 1 and TGF-beta 2 were hig her in maternal colostrum, but not in mature milk and infants' serum, in in fants with postweaning-onset atopic disease compared with those with prewea ning-onset disease (P = .0008 and P = .015, respectively), The concentratio n of TGF-beta 2 was, and that of TGF-beta 1 tended to be, higher in the col ostrum of mothers whose infants had specific IgA-secreting cells at 3 month s in response to at least one of the dietary antigens tested compared with those who did not have such cells (P = .048 and P = .076, respectively). Conclusion: TGF-beta in colostrum may prevent the development of atopic dis ease during exclusive breast-feeding and promote specific IgA production in human subjects.