HUC-MSCs can play a role in the treatment of SLE by inhibiting the proliferation of T cells, increasing the number of Treg cells, inhibiting the expansion of Tfh cells, maintaining the balance between T helper 1 and T helper 2 cells (Th1/Th2), and decreasing the level of TNF-α and IL-17 [37, 38]. The gene discussed is IL17A; the disease is systemic lupus erythematosus.