Measurement of soluble perforin, a marker of CD8+ T lymphocyte activation in epithelial lining fluid

The microsampling technique is safe and useful for separately obtaining ELF from central and peripheral airways. Levels of perforin in ELF from peripheral airways were significantly increased and correlated with the degree of pulmonary dysfunction. Perforin might reflect inflammation involving CD8+ T-lymphocytes. This novel biomarker might enable better understanding of the pathogenesis of COPD.