Among them, the expression of 18 cytokines (IL-1Rα, IL-2Rα, IL-4, IL-7, IL-8, IL-16, IL-17, Eotaxin, G-CSF, HGF, MCP-1, SCF, MIP-1α, PDGF-BB, RANTES, TNF-α, CTACK, and MIF) was significantly higher in the discovery cohort (IPF patients) than in the control group, even after adjustment for age, sex, and smoking history. The gene discussed is IL17A; the disease is idiopathic pulmonary fibrosis.