Allergic diseases are caused by the interaction between genetic factors and environmental factors. Maternal factors seem to influence the development of allergic diseases more than paternal ones. The underlying mechanisms of maternal factors remain to be clarified. Therefore, we hypothesized that miRNA in breast milk affect the development of allergic diseases in offspring.
METHODS: Total 24 mothers and 25 breastfed children were recruited. After taking informed consent from mothers, breast milk was collected on the day 3-5 after birth. MiRNAs were extracted by using mirVana miRNA PARIS kit. The amounts of miR-155, miR-21, and Let-7c were measured by qPCR. The children’s allergic status was checked at 10 months of age.
The miR-155 levels were higher in the breast milk fed to allergic children compared to non-allergic. The miR-21 levels in the milk from mothers having an allergic child significantly higher than that from non-allergic mothers. There was no significant difference in the Let7c levels between allergic and non-allergic children.
MiR-155 have been shown to affect Treg regulation, and miR-21 is known to ameliorate the differentiation and function of Th1 cells. Although further studies are required, some miRNAs in breast milk might be involved in the development of allergic diseases of breast mild-fed infant.