TGFB1 and systemic lupus erythematosus: The levels of IL-6, IL-17, IFN-γ, were significantly increased in patients with LN class IV than in those SLE patients without LN. The expression of Foxp3 genes was also significantly increased among class IV LN compared to those without; however, no significant difference was found in TGF-β expression between groups, suggesting the insufficient capacity of Treg to control the pathogenic role of IL-17-producing cells.