TNF and idiopathic pulmonary fibrosis: The pathogenesis of IPF is complex, and various proinflammatory factors such as transforming growth factor-β (TGF-β), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) have been confirmed to be involved in the two major stages of IPF development, namely inflammatory and fibrosis [3, 4].