Perforin, granzyme B, and FasL expression by peripheral blood T lymphocytes in emphysema

Abstract

Background: 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. 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.Methods: We 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.Results: Emphysematous 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.Conclusion: Despite 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. © 2007 Morissette et al; licensee BioMed Central Ltd.