IL-7 in colostrum is associated with atopic dermatitis at 9 months of age: A birth cohort in Japan.

Background: CCL25, CCL28, and IL-7 are present in breast milk and are known to contribute to the infant's thymus function and mucosal immune system. However, little is known about the relationship between the concentration of these cytokines/chemokines in breast milk and the development of atopic dermatitis (AD) in infancy. Objective: The purpose of this study was to investigate whether the concentration of these cytokines/chemokines in breast milk is related to the development of AD in infants. Methods: In this study, we measured the concentrations of cytokines/chemokines in colostrum collected within 5 days of birth and in breast milk collected at 1-month of birth in 281 infants belonging to a birth cohort using sandwich ELISA, and analyzed the relationship with the development of AD in infants at 9 months of age. Results: There was no association between CCL25 and CCL28 levels in breast milk and 9-month AD. On the other hand, IL-7 levels in colostrum ingested by AD infants were significantly higher than those ingested by non-AD infants (median, ng/mL: 0.186 vs 0.119, Mann-Whitney Conclusion: The results of this study show that IL-7 levels in breast milk may offer insights into the pathophysiological mechanisms of infantile AD.