CD40 up-regulation on dendritic cells correlates with Th17/Treg imbalance in chronic periodontitis in young population

We aimed to discover the influence of age on the development of chronic periodontitis and illustrate the molecular mechanism in this process. Blood samples were collected from 63 chronic periodontitis patients and 30 healthy controls. Th17 cell/Foxp3(+) regulatory T cell (Treg) ratio and expression of costimulatory molecules in dendritic cells (DCs) were analyzed by flow cytometry. The serum levels of soluble CD40 ligand (CD40L) and IL-17 were examined by ELISA. In young chronic periodontitis patients, the Th17/Treg ratio was significantly higher than that in old patients. CD40 on DCs and serum levels of CD40L and IL-17 were all higher in young chronic periodontitis patients. Mature DCs with high CD40 expression level elevated the Th17/Treg ratio in vitro. During the pathogenesis of chronic periodontitis, young patients had higher Th17/Treg ratio than old patients and this phenomenon was in line with the differential expression levels of CD40 in DCs.