Abstract
BackgroundIt is generally accepted that emphysematous lungs are characterized by an increase in the numbers of neutrophils, macrophages, and CD8+ T lymphocytes, the lasts having increased cytotoxic activity. Because systemic inflammation is also a component of emphysema, we hypothesize that peripheral CD8+ T lymphocytes of emphysematous smokers who show evidence of systemic inflammation will have higher expression of cytotoxic molecules.MethodsWe assessed parameters of systemic inflammation in normal individuals (smokers or non-smokers) and in emphysematous subjects with an active smoking history by measuring serum interleukine-6, C-reactive protein, and tumor necrosis factor. Expression of perforin, granzyme B, and FasL protein by CD8+ T lymphocytes, CD4+ T lymphocytes, and natural killer cells were assessed by flow cytometry while perforin, granzyme B, and FasL mRNA expression were measured on purified systemic CD8+ T lymphocytes by real-time PCR.ResultsEmphysematous smokers had higher levels of serum interleukine-6 than normal subjects. Even with the presence of systemic inflammation in emphysematous smokers, the percentage of peripheral CD8+ T lymphocytes, CD4+ T lymphocytes, and NK cells expressing perforin and granzyme B protein was not different between the three groups.ConclusionDespite evidence of systemic inflammation, peripheral T lymphocytes of emphysematous smokers did not show higher levels of cytotoxic markers, suggesting that increase of activated T lymphocytes in the emphysematous lung may be due to either activation in the lung or specific peripheral recruitment.
Highlights
It is generally accepted that emphysematous lungs are characterized by an increase in the numbers of neutrophils, macrophages, and CD8+ T lymphocytes, the lasts having increased cytotoxic activity
Subjects Twenty-nine subjects matched for age and sex were included in the study: nine were active smokers with evidence of emphysema and airflow limitation defined according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) [1] (FEV1 < 80% predicted value, FEV1/FVC < 70% predicted value, and reversibility ≤ 12% and 200 ml after salbutamol inhalation), 10 were smokers with normal lung function, and 10 were non-smokers with normal lung function
According to the GOLD index for chronic obstructive pulmonary disease (COPD) [1], two emphysematous smokers were classified as GOLD stage II, five as GOLD stage III, and two as GOLD stage IV
Summary
It is generally accepted that emphysematous lungs are characterized by an increase in the numbers of neutrophils, macrophages, and CD8+ T lymphocytes, the lasts having increased cytotoxic activity. Emphysema is a major component of chronic obstructive pulmonary disease (COPD) which is essentially induced by cigarette smoking or exposure to other noxious gases It is characterized by an inflammation-mediated destruction of the lung parenchyma which leads to distal air space enlargement and non-fully reversible airflow obstruction [1]. Chrysofakis et al [8] were able to document that perforin expression, a cytotoxic and activation marker, and cytotoxic activity of CD8+ T lymphocytes in the sputum of COPD smokers were higher than in smokers without COPD. All these data suggest that CD8+ T lymphocytes may have an important role in the pathogenesis of emphysema. Important systemic effects such as muscle wasting and cachexia are part of the disease [9,10]
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