The Study Of CD4~+CD25~+ Regulatory T Cells In The Pathogenesis Of Kawasaki Disease

Objective:To investigate the role of CD4+CD25+ regulatory T cells in the pathogenesis of Kawasaki disease(KD).Methods:Thirty-two patients with Kawasaki disease and thirty age-matched control subjects(15 febrile patients with common infection disease and 15 healthy children) were included in the study. Applying real time PCR(RT-PCR) to detect the expression of FOXP3 mRNA, and using flow cytometer(FCM) to determine the proportion of CD4+CD25+ regulatory T cells ,immune cells subsets , serum IFN-γ,IL-4 were detected by ELISA method. All patients with KD in this study were detected these parameters two times (before the intravenous immunoglobulin(IVIG) treatment and 2-3 days after relief of high fever due to IVIG treatment.)Results: compared with febrile patients with common infection disease(mean 6.37%) and healthy children(mean 7.45%), the proportion of CD4+CD25+ regulatory T cells in the KD children at acute phase(mean 4.40%) decresed significantly, while at defervescence phase, it increased obviously(mean 6.88%). The same results were found when concerning the FOXP3 mRNA expression , and there was postive relation between them(r=0.88,P<0.01). the proportion of CD3+CD4+,CD19+CD23+cells in the KD children at acute phase incresed significantly, but the decreased proportion of CD3+CD8+,CD16+CD56+ cells in these patients(P<0.01). 2-3 days after relief of high fever due to IVIG treatment, the proportion of CD3+CD4+,CD19+CD23+ decreased obviously(P<0.01) and proportion of CD3+CD8+ cells increased significantly(P<0.01), but as regard to the proportion of CD16+CD56+cells, no significant change was found(P>0.05) . serum IFN- γ,IL-4 increased obviously at acute phase of KD(P<0.01),and there were no significant decreasement of them 2-3 days after relief of high fever(P>0.05). Negative relation was found between the proportion of CD3+CD4+,CD19+CD23+ , serum IFN-γ,IL-4 and FOXP3 mRNA expression , the proportion of CD4+CD25+ regulatory T cells at acute phase of KD(P<0.01),but there were no significant relation between the proportion of CD3+CD8+,CD16+CD56+ cells and FOXP3 mRNA expression , the proportion of CD4+CD25+ regulatory T cells(P>0.05). 2-3 days after relief of high fever due to IVIG treatment, the negative relation were also found between the proportion of CD3+CD4+,CD19+CD23+ cells and FOXP3 mRNA expression , the proportion of CD4+CD25+ regulatory T cells(P<0.01), while no siginficant relation when concerning the serum IFN-γ,IL-4 and FOXP3 mRNA expression , the proportion of CD4+CD25+ regulatory T cells(P>0.05).Conclusion: CD4+CD25+ regulatory T cells might take part in the pathogenesis of KD, reduced suppressive effect on some immune cells due to decreased CD4+CD25+ regulatory T cells, hence excessive activation of immune system and the pathogenesis of KD.