Study on Foxp3 promoter region methylation of mononuclear cells in patients with rheumatoid arthritis / 中华风湿病学杂志

ABSTRACT

Objective By detecting the expression levels of Foxp3 in CD4+CD25+ regulatory T cells of peripheral blood mononuclear cells (PBMCs) in rheumatoid arthritis (RA),and the Foxp3 gene promoter region methylation to explore its role in the pathogenesis of RA.Methods Twenty-five RA patients and 10 healthy controls were selected,and the PBMCs were extracted by density gradient centrifugation.Foxp3 expression levels of CD4+CD25+ regulatory T cells were detected by flow cytometry.The real-time fluorescence quantitative PCR assay was used to detect the Foxp3 mRNA expression in PBMCs; and bisulfate processing gene sequencing was used to determinethe differences in Foxp3 gene promoter sequence methylation level of PBMCs.The comparison between groups was analyzed using one-way ANOVA; two sets of qualitative data were compared using Fisher's exact test.Results The expression levels of Foxp3 mRNA in the CD4+CD25+regulatory T cells of active RA patients (2.31±0.25) was significantly lower than inactive RA group (3.68±0.26) and healthy controls (5.67±0.34),the difference was statistically significant (P＜0.05).The Foxp3 mRNA expression level in inactive RA group was lower than that of the healthy controls (P＜0.05).Foxp3 promoter region-67,-74 sites of methylation level in PBMCs of RA patients (46％) was significantly higher than that of the healthy controls (6％).Conclusion Reduction in the number of CD4+CD25+ regulatory T cells may be involved in the pathogenesis of RA and Foxp3 gene promoter methylation levels plays a key role in this process.