SIRT1 and systemic lupus erythematosus: In one study, CD4+ T cells isolated from SLE patients transfected with SIRT1-siRNA showed inhibition of DNA methyltransferase 1 (DNMT1) activity; Th17 cytokines, such as IL-17A, IL-22, and IL-23, were positively correlated with disease activity and severity, and a higher proportion of Th17 cells was found in patients with active SLE and high levels of serum IL-17 (126).