TY - JOUR T1 - What cells are replacing the epithelium in cystic remodeling in UIP and COPD JF - European Respiratory Journal JO - Eur Respir J DO - 10.1183/13993003.congress-2020.3380 VL - 56 IS - suppl 64 SP - 3380 AU - Florian Gallob AU - Luka Brcic AU - Tamas Zombori AU - Sylvia Eidenhammer AU - Wim Timens AU - Helmut H. Popper Y1 - 2020/09/07 UR - http://erj.ersjournals.com/content/56/suppl_64/3380.abstract N2 - Remodeling in usual interstitial pneumonia (UIP) results in the repopulation of alveolar remnants by cuboidal cells. It is speculated that these cells might migrate from the proximal bronchial airways, facilitated by the secretion of chemokines from senescent cells. Senescent cells have also been identified in chronic obstructive lung disease (COPD), and remodeling might also occur in this disease.Tissues from cases of IPF, chronic autoimmune disease (CAD) and chronic hypersensitivity pneumonia (CHP) all with UIP pattern, and cases of COPD were chosen. Sections were incubated with antibodies for cytokeratins 5/6, 7, 8, 9. 14, 17, 18, 19, and p40, TTF1, and Clara cell protein 10 (CC10).Cell in remodeling areas of IPF, CAD, CHP stained for cytokeratin 5, single cells also acquired CK14; almost all cells stained for CK8/18. The cells were positive for TTF1 and p40. The reaction for CC10 was seen in few cells. Basal cells of bronchioles including the terminal ones stained for CK5/6 and p40, whereas the differentiated cells in the upper layer were positive for CK8/18 and CC10. Cells from the basal layer of bronchioles migrate into the denuded alveolar region and repopulate the remodeled cystic areas. At this position they acquire TTF1, initially not expressed. The expression of the so-called squamous cell marker p40 in basal cells of bronchioles and in the cystic areas was unexpected, as squamoid morphology was absent; if these cells give rise to squamous metaplasia cannot be answered. A coexpression with CK14 is rarely found, other cytokeratins associate with CK5. Also, in COPD CK5/6 positive cells increase in number and replace pneumocytes in emphysematous areas and increase within bronchi.FootnotesCite this article as: European Respiratory Journal 2020; 56: Suppl. 64, 3380.This abstract was presented at the 2020 ERS International Congress, in session “Respiratory viruses in the "pre COVID-19" era”.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only). ER -