Epithelial mesenchymal transition (EMT) in small airways of COPD patients

We congratulate Milara et al 1 for getting a paper suggesting that epithelial mesenchymal transition (EMT) is important in the pathogenesis of chronic obstructive pulmonary disease (COPD) into a top respiratory journal. This is quite a breakthrough. In the discussion, Milara et al were somewhat dismissive of our findings on EMT markers in large airways of COPD patients;2 commenting that our study was limited by the mesenchymal protein expressions analysed (MMP-9, S100A4, vimentin) being potentially expressed by inflammatory cells. In a follow-up paper3 we excluded such confounding. Further, our study illustrated that cells in the basal epithelium, and reticular basement membrane (Rbm) in smokers/COPD double-stain for cytokeratin-(s) and the ‘EMT marker’ S100A4, confirming a likely epithelial …