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). The gene discussed is PDCD1; the disease is systemic lupus erythematosus.