Cytotoxic phenotype of alveolar lymphocytes (AL) in bronchoalveolar lavage fluid (BALF) from non-small cell lung cancer (NSCLC) patients

Background . T lymphocytes are key regulators of the antitumor immunity. Their ability to control local immune response in tumor microenvronment as well as induce tumor cells death is considered the most important . Aim. To evaluate phenotypic properties of AL in NSCLC with particular attention to the markers of T cell cytotoxicity. Methods. Bronchoalveolar lavage fluid (BALF) was harvested in tumor-free lung region from patients with NSCLC (n=15) and healthy volunteers as controls (n=13). AL were phenotyped by flow cytometry for specific surface markers: CD3, CD4, CD8, CD19, CD16, CD56, CD25, CD27 and CD45RO. Cytotoxicity was evaluated in both Th and Tc cells by extracellular (FasL, TRAIL) and intracellular (granzyme B) marker expression. Results . CD4/CD8 ratio was higher in NSCLC patients as compared to controls (1.2±0.3 vs 0.9±0.7 for smokers). AL from NSCLC patients demonstrated increased expression of FasL, (particularly CD4+ cells: 13±7.5 vs 2.3±1.7%, p<0,05), TRAIL (for all AL) and NK cells (8.0±2.1 vs 4.0±1.1%). Granzyme B expression was similar in NSCLC and control groups. Unexpectedly, nTreg (assessed as CD4+25+27+ cells) percentage was lower in NSCLC than in healthy controls. Conclusion. AL from NSCLC patients, including Th cells demonstrate increased cytotoxic potential (FasL+ cells, TRAIL+ cells, NK cells).