TLR2 and chronic obstructive pulmonary disease: Indeed we found that TLR-2 (but not TLR-4) expression was up-regulated in monocytes of COPD patients (both when clinically stable and during AECOPD), and that these cells secreted elevated levels of inflammatory mediators upon challenge with preparations containing TLR-2 agonists (but not with LPS) (fig 2).