Detect The Methylation Status Of The FOXP3 Gene Promoter In CD4~+ CD25~+ T Cell Of Patients With Rheumatoid Arthritis

Objective:To detect the expression of foxp3 on CD4~+CD25~+ regulatory T cell in peripheral blood of patients with rheumatoid arthritis,and to detect the methylation status of the FOXP3 gene promoter in peripheral blood CD4~+CD25~+ regulatory T cell of patients with rheumatoid arthritis and its role in the pathogenesis of RA.Method :25 RA patients and 25 healthy controls were recruited according to the collection standard, which include 16 new-onset patients with active RA and 9patients with inactive RA.The disease activity was measured by the DAS28.Levels of FOXP3 in CD4~+CD25~+T cell assay was analyzed by flow cytometry. PBMCs of RA patients and healthy controls were isolated by Ficoll-Hypaque density gradient centrifugation . The methylation status difference of the FOXP3 promoter in PBMCs between RA patients and healthy controls was detected by bisulfite sequencing technology.Results:1. It was showed by flow cytometry that the percentage of CD4~+CD25~+FOXP3~+T cells in patients with active,inactive RA and controls was 2.39%±0.12,3.77%±0.26,4.84%±0.21.The percentage of CD4~+CD25~+FOXP3~+T cell in active and inactive RA patients were significantly lower than those of healthy controls(p<0.05).2. The percentage of CD4~+CD25~+FOXP3~+T cells in RA patients shows negative correlations with DAS28 .3. The methylation status of the FOXP3 promoter in PBMCs in patients with RA was more than those of healthy controls. The results are statistically significant.Conclusion:1. The percentage of CD4~+CD25~+FOXP3~+T cells in RA patients were significantly lower than those of healthy controls. Lack of FOXP3 on CD4~+CD25~+T cells may have an important role in the pathogenesis of rheumatoid arthritis ,and can reflect disease activity .2. The increase of the methylation status of the FOXP3 promoter -67,-74 site in PBMCs in patients may be involved in RA. The effective interventions for the treatment of RA can be designed to follow the mechanism , it is a new theoretical foundation.