To examine whether the TSDRs of CD4+Foxp3+ T cells in SLE patients were demethylated, CD4+Foxp3+ and CD4+Foxp3− cells were individually isolated from the PBMCs of 6 active SLE patients and 6 heathy controls using flow cytometer-based sorting and subjected to methylation-specific PCR (Fig. 3a and b). This evidence concerns the gene FOXP3 and systemic lupus erythematosus.