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.
Keywords: COPD, TLR stimulation, cigarette smoke, DAMPs.
