Roles of CD4+ CD25+ regulatory T cells and T helper 17 cells in the pathogenesis of Kawasaki disease

Objective To observe the changes in CD4+ CD25+ regulatory T cells(Treg) and T helper 17 cells(Th17) cells′ proportions in the peripheral blood in children with Kawasaki disease(KD) before and after the treatment, and to analyze the role of Treg/Th17 cell imbalance in the pathogenesis of KD. Methods Fifty-two children with acute KD(KD group) and 34 age-matched healthy children(healthy control group) were selected at Jiangxi Provincial Children′s Hospital from April to December of 2014.Morning peripheral vein blood was collected from 2 groups: one before the treatment by Immunoglobulin and Aspirin, and the other 3 days after defervescence treatment.Flow cytometry was used to detect proportions of Treg cells and Th17 cells in the peripheral blood.The enzyme linked immunosorbent assay was used to detect the levels of interleukin(IL)-6, IL-10, IL-17, IL-23 and transforming growth factor(TGF)-β. Results Proportion of Treg cells in the acute KD group was remarkably lower than that in the healthy control group [(1.48±0.21)%vs.(5.13±0.32)%, t=28.41, P<0.05], but it was significantly increased after treatment, and there was a significant difference[(4.71±0.36)%vs.(1.48±0.21)%, t=-23.32, P<0.05]. Proportion of Th17 cells in the acute KD group was markedly higher than that in the healthy control group[(8.06±0.48)%vs.(2.65±0.50)%, t=-23.47, P<0.05], which was significantly decreased after treatment[(3.04±0.35)%vs.(8.06±0.48)%, t=25.55, P<0.05]. Compared with the healthy control group, the levels of serum IL-6, IL-17, IL-23 in the acute KD group were significantly increased before treatment, and there were significant differences [(34.53±0.53) ng/L vs.(10.88±0.83) ng/L, t=-72.36; (57.05±0.78) ng/L vs.(14.29±0.98) ng/L, t=-55.29; (45.18±1.52) ng/L vs.(18.25±1.08) ng/L, t=-43.27; all P<0.05], but after treatment the levels were significantly decreased[(14.94±1.06) ng/L vs.(34.53±0.53) ng/L, t= 49.63; (27.64±0.91) ng/L vs.(57.05±0.78) ng/L, t= 26.49; (24.50±1.13) ng/L vs.(45.18±1.52) ng/L, t= 32.17; all P<0.05]. The levels of serum IL-10, TGF-β in the acute KD group significantly decreased than those of the healthy control group, and there were significant differences [(14.29±0.64) ng/L vs.(29.57±0.87) ng/L, t=42.24; (16.88±0.90) ng/L vs.(38.83±0.84) ng/L, t=53.51; all P<0.05 ], but after treatment the levels were significantly increased, and there were significant differences [(23.01±0.61) ng/L vs.(14.29±0.64) ng/L, t=-29.54; (33.47±0.82) ng/L vs.(16.88±0.90) ng/L, t=-40.68; all P<0.05 ]. Conclusion Imbalance between Treg cells and Th17 cells may be an important cause for the immune disorder of KD, the changes in related cytokines are involved in the pathogenesis of KD. Key words: CD4+ CD25+ regulatory T cell; T helper 17 cell; Kawasaki disease