Ex vivo, IL-2 stimulation downregulated the expression of PD-1 along with the increased expression of Foxp3 and CTLA-4 on cTfr cells (68), and converted memory Tfh cells to cTfr cells by promoting STAT3 and STAT5 phosphorylation in SLE patients (34). This evidence concerns the gene FOXP3 and systemic lupus erythematosus.