CD8+T lymphocytes in peripheral airways of lungs with different types of emphysema

COPD is one of leading cause of death, but pathogenesis was not yet elucidated. A histopathologic study has demonstrated increased number of CD8+ T lymphocytes in peripheral airways of COPD, which are sites responsible for chronic airflow limitation. Some smokers develop centrilobular emphysema (CLE) with higher degree of small airways disease and others panlobular emphysema (PLE) with smaller degree, suggesting different pathogenetic mechanism. We reasoned that CLE lung might have higher no. of CD8+ T cells in peripheral airways than PLE. To test this hypothesis immunohistochemical study, using monoclonal antibody, was done in microscopically classified 8 normal, 7 PLE and 7 CLE lungs. Walls of at least 5 small airways from each case were examined to count CD8+ T cells. Results were expressed as no. of cells/mm(2) of tissue. CD8+ T lymphocyte counts in peripheral airways of normal, PLE and CLE lungs were 6.75 +/- 5.95, 12.10 +/- 6.58, and 43.65 +/- 35.95 cells/mm(2), respectivel., (p < 0.001). No significant difference between normal and PLE lungs, but significant differences between normal and CLE lungs and between PLE and CLE lungs (p < 0.001). In conclusion, these findings suggest that CD8+ T lymphocytes might play a role in the pathogenesis of CLE, but not in PLE.