The results showed that the proportion of Th17 cells in IL-9 and SSc serum groups was significantly higher than that in the control group; however, the proportion of Th17 cells in the IL-9 neutralizing antibody group was significantly lower than that in the control group, and IL-9 neutralizing antibody decreased the promoting effect of serum on Th17 cells (Fig. 4A). The gene discussed is IL9; the disease is systemic sclerosis.