IL6 and pulmonary fibrosis: In addition, IL-17 is a multifunctional cytokine produced by Th17 cells, which is involved in the pulmonary fibrosis process via recruiting and activating neutrophils and even other cytokines, such as transforming growth factor-β1 (TGF-β1), IL-1β, IL-6, and IL-13 (41, 42).