Investigation of the methylation status of Foxp3 gene during acute phase of Kawasaki disease / 中华微生物学和免疫学杂志

ABSTRACT

Objective To investigate the methylation status of Foxp3 gene and its roles in immunological pathogenesis of Kawasaki disease(KD). Methods Thirty children with KD and eighteen agematched healthy children consented to participate in this study. Quantitative methylation specific polymerase chain reaction(MSQP) was used to assess the methylation status of Foxp3 promoter and regulatory T cells specific demethylated region(TSDR) in CD4+ T cells. The proportion of CD4+ CD25 + Foxp3 + regulatory T (Tr) cells was analyzed by flow cytometry. Transcriptional levels of CD4+ CD25 + Foxp3 + Tr associating genes (Foxp3, CTLA4, GITR, LAG3 and CCR8 ) and Foxp3-dependent molecules (UBD and LGAIS3)were measured by real-time PCR. Results ( 1 ) Demethylation level of Foxp3 promoter in CD4 + T cells from patients with KD was lower significantly than that of health subjects( P ＜ 0.01 ), and increased significantly after treated with intravenous gamma globulin therapy(IVIG) (P ＜ 0.01 ). No difference of demethylation level of TSDR region was observed among all groups ( P ＞ 0. 05 ). ( 2 ) The proportion of CD4 + CD25 + Foxp3 + Tr in peripheral blood from patients with KD , as well as mRNA levels of Foxp3 gene in CD4+ T cells, was significantly lower than those of health subjects ( P ＜0. 01 ), and increases significantly after IVIG therapy (P ＜0.01 ). Significant positive correlations between demethylation level of Foxp3 promoter and the proportion of CD4 + CD25 + Foxp3 + Tr , or expression levels of Foxp3 in CD4 + T cells, were observed during acute phase of KD (CD4+CD25+ Foxp3+ Tr r=0.76, P＜0. 01; Foxp3 r=0.89, P＜0. 01). (3)Transcription level of CD4+ CD25+ Foxp3+ Tr associating factors, such as CTLA4, GITR, LAG3 and CCR8, was significantly down-regulated in acute phase of KD(P＜0. 01 ), and up-regulated to some extent after treated with IVIG(P ＜0. 01 ). Expression levels of Foxp3-dependent molecules UBD and LGALS3 in CD4 + T cells decreased significantly during acute phase of KD (P ＜ 0.01 ), and basically recovered to the levels of health subjects( P ＜ 0.01 ). Conclusion Decrease of demethylation level of Fopx3 promoter is correlated with immune dysfunction in Kawasaki disease.