TNF and pulmonary fibrosis: Inflammatory factors such as interleukin-17 (IL-17), interleukin- 6 (IL-6), interleukin-13 (IL-13), and tumor necrosis factor-α (TNF-α) play an important role in the formation of alveolar epithelial cell (AEC) apoptosis and matrix fiber repair and are activated in the early stage of pulmonary fibrosis [4].