Danger-Associated Molecular Patterns and Danger Signals in Idiopathic Pulmonary Fibrosis

The chronic debilitating lung disease, idiopathic pulmonary fibrosis (IPF), is characterized by a progressive decline in lung function, with a median mortality rate of 2–3 years after diagnosis. IPF is a disease of unknown cause and progression, and multiple pathways have been demonstrated to be activated in the lungs of these patients. A recent genome-wide association study of more than 1,000 patients with IPF identified genes linked to host defense, cell–cell adhesion, and DNA repair being altered due to fibrosis (Fingerlin, et al. Nat Genet 2013;45:613–620). Further emerging data suggest that the respiratory system may not be a truly sterile environment, and it exhibits an altered microbiome during fibrotic disease (Molyneaux and Maher. Eur Respir Rev 2013;22:376–381). These altered host defense mechanisms might explain the increased susceptibility of patients with IPF to microbial- and viral-induced exacerbations. Moreover, chronic epithelial injury and apoptosis are key features in IPF, which might b...