A specific DAMP profile identifies susceptibility to smoke-induced airway inflammation

Abstract

To the Editor: Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality, with a worldwide prevalence of 9–10% [1]. COPD is associated with chronic, neutrophilic inflammation in the lungs, causing destruction of lung parenchyma (emphysema) and/or remodelling of the airways with mucus hypersecretion (bronchitis) [2]. Chronic exposure to noxious particles and gases, such as cigarette smoke, is the major risk factor for COPD, while susceptibility to the disease has a strong genetic component [2]. While the activity of the innate immune system increases with disease progression during early stages of COPD, the precise nature of the factors that trigger innate immune responses in COPD is currently unknown. Cell damage and death upon exposure to cigarette smoke in COPD may induce the release of damage associated molecular patterns (DAMPs) [3]. Elevated levels of several prototypic DAMPs, including high-mobility group box (HMGB)1, heat shock proteins (HSPs) and S100A8, have been observed in bronchoalveolar lavage (BAL) fluid, serum and epithelial lining fluid of COPD patients [4–6]. DAMPs activate cells of the innate immune system upon binding to pattern recognition receptors, such as toll-like receptors (TLRs) and receptor for advanced glycation end-products (RAGE). Importantly, the AGER gene, which encodes the RAGE receptor, is a genome-wide association study susceptibility gene for COPD [7]. To date, studies investigating the role of DAMPs in COPD have focused on the analysis of a single DAMP. However, while each individual DAMP triggers …