Investigation Of The Change Of Th17 Cells During Acute Phase Of Kawasaki Disease

Investigation of the change of Th17 cells during acute phase of Kawasaki diseaseObjective Kawasaki Disease (KD) is an acute vasculitis that affects infants and children, and is the leading cause of aquiver heart disease in pediatric age group. The immunopathogenesis of KD are required to be investigated. A great deal of studies have found that the levels of many pro-inflammatory cytokines such as TNF-a, IL-6 can be elevated in acute KD, which the mechanism resulting in aberrant immune function or over expression of pro-inflammatory cytokines are not very clear. T help 17 cells (Th17), recently identified as a subset of helper T cells which could secret interleukin-17, induces expression of proinflammatory cytokines and chemokines. Treg cells expressing the fork head/winged helix transcription factor (Foxp3) have an anti-inflammatory role and maintain tolerance to self components by contact-dependent suppression (CTLA-4) or releasing anti-inflammatory cytokines [interleukin (IL)-10 and transforming growth factor (TGF)-β1]. The study is designed to investigate the changes and roles of Th17/Treg cells in immunological pathogenesis of KD. In addition, we explore the alteration and significance of Th17 cells in patients with intravenous immune globulin-resistant KD. Methods 1:45 children with KD and 30 age-matched healthy children were enrolled. Real-time PCR were used to evaluate the mRNA levels of IL-17A/F, ROR-γt and Foxp3 in CD4-positive cells. The proportion of Th17 and Treg cells were analyzed by flow cytometry. Plasma cytokine (IL-17A, IL-6, IL-10, IL-23 and TGF-β) concentrations were measured by enzyme-linked immunosorbent assay (ELISA).2:Forty-five children with KD (thirty-five sensitive group and ten resistant group) and Thirty age-matched healthy children were studied. Real-time PCR were used to evaluate the mRNA levels of ROR-yt. The proportion of Th17 in peripheral blood were detected by flow cytometric analysis.Th17-related plasma cytokines (including IL-17A and IL-6) concentrations were measured by enzyme-linked immunosorbent assay (ELISA). Results 1:The Th17/Treg imbalance in patients with acute KD:①Significant positive correlation between IL-17A/F and erythrocyte sedimentation rate(ESR), C-reactive protein(CRP) and White blood cells(WBC) were observed during acute phase of KD (IL-17A:0.70,0.85,0.80, P＜0.01; IL-17F:0.63,0.65,0.69, P＜0.01).②Th17 cells proportions, and expression levels of cytokines (IL-17A/F) and transcription factors (ROR-γt) were significantly up-regulated, while Treg proportions, and expression levels of Treg transcription factor (Foxp3) were significantly down-regulated in children with acute KD(P＜0.01). There was no obvious difference between the KD-CAL+ group and KD-CAL- group in the proportions of Treg cells, while Th17 proportions in the KD-CAL+ group were markedly higher than that of the KD-CAL- group(P＜0.01).③The plasma IL-17A, IL-6 and IL-23 concentrations in patients with KD were significantly higher compared with the concentrations in NC. Plasma IL-10, TGF-βconcentrations was markedly lower in the KD group than NC group (P＜0.01).2:Significance and alteration of Thl7 cells in immune globulin-resistant KD:①Compared with healthy controls, the Th17 cells proportions, the expression levels of cytokines (IL-17A/F) and transcription factors (ROR-γt) were significantly up-regulated during acute phase of KD (P＜0.01).②Compared with sensitive group, the expression levels of cytokines (IL-17A/F) and transcription factors (ROR-γt) were significantly up-regulated in immune globulin-resistant KD (P＜0.01), and down-regulated after treatment with intravenous immunological globulin (IVIG) therapy in sensitive group (P＜0.01), but there was no significant difference in the elevated levels of the cytokines and ROR-yt mRNA expression in resistant group(P＞0.05). There were a significant difference in plasma IL-17A,IL-6 before or after IVIG between resistant and non-resistant group (P＜0.01).③Compared with the normal controls, plasma IL-17A, IL-6 were markedly elevated in patients with KD. There were a significant difference in plasma IL-17A and IL-6 concentrations between resistant and sensitive group before IVIG treatment (P＜0.01). The resistant group showed also significantly high IL-17A,IL-6 after IVIG. There was no significant difference in the severity of decrease between before and after IVIG within both groups, but it was found that plasma IL-17A and IL-6 had a tendency to decrease after treatment with IVIG.④Methylprednisolone might down-regulate inflammatory response through inhibiting the secretion of inflammatory IL-6 and IL-17A cytokines in acute stage of immune globulin-resistant KD. Treatment of immune globulin-resistant KD with IVMP resulted in faster resolution of fever, more rapid improvement in markers of inflammation. Conclusions①Th17/Treg cells imbalance exists in the patients with KD; Th17/Treg cells imbalance may be one of factors causing disturbed immunological function in KD.②Aberrant activation of Th17 cells may be one of factors resulting in immune globulin-resistant KD.