IL-17 induces the production of other proinflammatory cytokines, such as IL-1 and IL-6 [47]; cooperates with IL-23 and other Th-17-related cytokines, for instance, IL-17F and IL-21, to form a complex network to promote inflammation response and amplify the tissue damage induced by SLE [48]; and improves B-cell proliferation and excessive production of autoantibodies in SLE patients [49, 50]. This evidence concerns the gene IL21 and systemic lupus erythematosus.