LPS-stimulation of TLR2 protein and mRNA on alveolar macrophages (AM). (A) Flow cytometry expression. rMFI (± SD) is shown from non-smokers (young n = 10, elderly n = 7), smokers (n = 10) and COPD patients (n = 14). rMFI = relative mean fluorescence intensity. * = p < 0,04. In situ hybridization targeting TLR2 mRNA of HOPE-fixated BAL cells. Cells from non-smokers before (B) and after (C [young], D [elderly]) LPS-stimulation. Cells from COPD patients (E) after LPS-stimulation (Anti-DIG-AP-New-fuchsine; 600x).