To study the functional response of TLRs, purified monocytes harvested from AECOPD patients at admission, stable COPD patients, smokers or never smokers were stimulated with PGN or highly purified LPS (stimuli that signal through TLR-2 and TLR-4 respectively) and the amounts of TNFα and IL-6 secreted taken as read-out for monocyte activation. This evidence concerns the gene TLR4 and chronic obstructive pulmonary disease.