Decreased Treg-derived miR-181a and miR-155 correlated with reduced number and function of Treg cells in allergic rhinitis children.

Background: Regulatory cells (Tregs) have been proved to be deeply involved in allergic airway inflammation. This study aims to evaluate the expression of miRNA in children with AR and their association with Tregs as well as the severity of AR.

Methods: Twenty-five AR children and 20 healthy children were enrolled in this study. The Treg-cell percentage and expression of IL-10 and TGF-β were detected by flow cytometry and enzyme-linked immunosorbent assay. The microRNA microarray analysis in purified Tregs was performed and differentially expressed microRNAs were confirmed by quantitative polymerase chain reaction (qPCR).

Results: Children with AR had lower percentage of Tregs and expression of IL-10 and TGF-beta compared with control children. We found that significantly lower levels of miR-155 and miR-181a in Tregs from AR than healthy controls. Furthermore, intracellular miR-155 and miR-181a level were positively correlated with percentage of Tregs and expression of IL-10 and TGF-beta. Similarly, total nasal severity scores (TNSS) were found to be negatively correlated with miR-155 and miR-181a levels.

Conclusion: Decreased Treg-derived miR-181a and miR-155 were correlated with reduced number and function of Tregs in AR children. The intracellular miR-155 and miR-181a levels may serve as predictors of disease severity in childhood AR.