Differential lymphocyte infiltration in small airways and lung parenchyma in COPD patients.
BACKGROUND
In COPD, although histological lesions at both the small airways (wall thickening and tissue remodeling) and lung parenchyma (emphysematous destruction) are definitely different, the inflammatory cells involved in both processes are the same. Our study aims to determine if these histopathological phenotypes are related to two different lymphocyte profiles.


METHODS
Distribution and cell density of CD3(+), CD4(+), CD8(+) and B lymphocytes were compared in small airways and parenchymal interstitium of 9 non-smokers, 18 smokers without COPD, 16 smokers with moderate COPD and 16 patients with very severe COPD undergoing lung transplantation. Spatial distribution of lymphocytes in periemphysematous parenchyma was also assessed.


RESULTS
CD3(+) and B cell densities were significantly higher in small airways than parenchyma interstitium of very severe COPD patients. Furthermore, CD8(+) cells were increased in the epithelium of airways of moderate COPD patients compared to non-smokers. Although CD8(+) cell density was increased in parenchyma of COPD patients, CD8(+) and B cell densities were similar when comparing periemphysematous and non-emphysematous alveolar interstitium.


CONCLUSIONS
In COPD, it is true that the small airways' wall shows a clear inflammatory pattern, with a high mononuclear infiltration and tissue remodeling. However, parenchymal interstitium shows a milder CD8(+) infiltration which, moreover, is not spatially related to emphysematous destroyed areas.
Olloquequi
Jordi
J
Departament de Biologia Cel-lular, Universitat de Barcelona, Barcelona, Spain. jordiog82@gmail.com
Ferrer
Jaume
J
Montes
Juan F
JF
Rodríguez
Esther
E
Montero
M Angeles
MA
García-Valero
José
J
D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000473:pathology*; D005260:Female; D006801:Humans; D008168:Lung / Q000276:immunology / Q000473:pathology*; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000276:immunology / Q000473:pathology*; D012907:Smoking / Q000276:immunology / Q000473:pathology