Pulmonary fibrosis is a chronic lung disease characterized by excessive accumulation of extracellular matrix (ECM) and remodeling of the lung architecture. Idiopathic pulmonary fibrosis is considered the most common and severe form of the disease, with a median survival of approximately three years and no proven effective therapy. Despite the fact that effective treatments are absent and the precise mechanisms that drive fibrosis in most patients remain incompletely understood, an extensive body of scientific literature regarding pulmonary fibrosis has accumulated over the past 35 years. In this review, we discuss three broad areas which have been explored that may be responsible for the combination of altered lung fibroblasts, loss of alveolar epithelial cells, and excessive accumulation of ECM: inflammation and immune mechanisms, oxidative stress and oxidative signaling, and procoagulant mechanisms. We discuss each of these processes separately to facilitate clarity, but certainly significant interplay will occur amongst these pathways in patients with this disease.

Review on three IL‐4‐related branch points for immune regulation: alternative splicing of IL‐4, differential receptor engagement, and differential regulation of macrophage activation by IL‐4.

The type 2 pattern of cytokine mRNA produced by BAL cells from SSc patients differs from unopposed IFNgamma production found in healthy BAL cells. This production of type 2 cytokine mRNA by CD8+ T cells is associated with a significant decline in lung function over time, which suggests a pathologic role for these T cells in interstitial fibrosis in SSc.