Abstract

Chronic obstructive pulmonary diseases (COPD) are chronic inflammatory diseases in which exacerbations can be associated with viral or bacterial infections. The innate immune system is the first line of defense against cigarette smoke, pollutants, occupational exposures, pathogens and tissue injury and is responsible for resolving infections and repairing damaged tissues. Initiation of the innate immune response is triggered by recognition of pathogen- or danger-associated molecular patterns (PAMPs and DAMPs) by pathogen recognition receptors (PRRs). The most studied PRRs are the Tolllike receptors (TLRs) which are localized either to the cell surface or within endosomes. Activation of TLRs induces the recruitment of innate immune cells, initiates tissue repair processes, and results in adaptive immune activation; importantly these processes are abnormal in COPD. Understanding the roles of TLRs in the pathogenesis of chronic inflammatory pulmonary disease, may provide novel targets for the prevention and/or treatment of COPD.