Tc2 response at the onset of COPD exacerbations.
BACKGROUND
T lymphocytes and especially the subpopulations of CD8+ cells are believed to have a key role in COPD pathophysiology, but there are only few data regarding the role of these cells in COPD exacerbation.


OBJECTIVE
We aimed to study prospectively changes of CD8+ T-lymphocyte subpopulations in the sputum of COPD patients at the onset of mild exacerbations and at a stable condition in order to provide further insight in the pathophysiology of the disease.


METHODS
Induced-sputum samples were collected from 24 COPD patients with median age of 52 years (interquartile range [IQR], 44 to 58 years) and FEV(1) percentage of predicted of 78.05% (IQR, 75.8 to 80.1%) at the onset of mild exacerbations not requiring hospitalization and when stable. Inflammatory cells and T-lymphocyte subpopulations (CD4+, CD8+, and cells producing interferon [IFN]-gamma or interleukin [IL]-4) were measured using flow cytometry and immunocytochemical methods.


RESULTS
A significant increase in sputum CD8+ T lymphocytes (p < 0.0001) and significant decreases in CD4+ T lymphocytes as well as in CD4+/CD8+ (p = 0.0001) and CD8+IFN-gamma+/CD8+IL-4+ (p = 0.001), CD4+IFN-gamma+/CD4+IL-4+ (p = 0.0003) sputum cells ratios were found decreased at the onset of exacerbations compared to stable condition. The changes in T-lymphocyte subpopulations were not associated with smoking history, demographic characteristics, or disease severity.


CONCLUSIONS
The findings of the present study suggest that CD8+ lymphocytes are increased and potentially polarized toward a Tc2 profile in the airways of COPD patients at the onset of COPD exacerbations with respect to stable condition. The clinical impact of the observed phenomenon requires further investigation.
Makris
Demosthenes
D
Department of Thoracic Medicine, University Hospital, Medical School, University of Larisa, Larisa. Electronic address: appollon7@hotmail.com.
Lazarou
Stelios
S
Department of Thoracic Medicine, University Hospital, Medical School, University of Larisa, Larisa.
Alexandrakis
Michael
M
Department of Hematology, Medical School, University of Crete, Heraklion, Greece.
Kourelis
Taxiarchis V
TV
Department of Hematology, Medical School, University of Crete, Heraklion, Greece.
Tzanakis
Nikos
N
Department of Epidemiology, Medical School, University of Crete, Heraklion, Greece.
Kyriakou
Despina
D
Department of Hematology, University Hospital, Medical School, University of Larisa, Larisa.
Gourgoulianis
Kostas I
KI
Department of Thoracic Medicine, University Hospital, Medical School, University of Larisa, Larisa.
D000328:Adult; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000473:pathology / Q000502:physiology*; D018414:CD8-Positive T-Lymphocytes / Q000473:pathology / Q000502:physiology*; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D015847:Interleukin-4 / Q000378:metabolism; D016131:Lymphocyte Subsets / Q000473:pathology / Q000502:physiology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology*; D013183:Sputum / Q000166:cytology; D013602:T-Lymphocytes, Cytotoxic / Q000473:pathology / Q000502:physiology*
D015847:Interleukin-4; D007371:Interferon-gamma