These results showed that IL-9 and SSc serum significantly promotes the secretion of IL-17 by immature T-lymphocytes, while IL-9 neutralizing antibody and tanshinone IIA significantly inhibit the secretion of IL-17 by immature T-lymphocytes and reverse the triggering effect of IL-9 and SSc serum (Fig. 4C). Here, IL17A is linked to systemic sclerosis.