IL23A and systemic lupus erythematosus: Several studies have shown that IL-23 is an important promoter of Th17 cell differentiation and factor in Th17 cell development, expansion, and proliferation.211 Using anti-IL-23 mAbs for the treatment of active SLE is a promising approach.30 Th17 differentiation in vivo is also influenced by the balance between Th17 and Treg cells.212–214 In patients with SLE, Treg cells decrease and Th17 cells increase.