Expression of Fas antigen in the cells from bronchoalveolar lavage fluid (BALF).

Fas antigen is a cell surface receptor protein that mediates apoptosis expressed in various cells. In this study Fas expression was examined in cells of patients with lung diseases in which changes in the lung immunology were documented. We have performed bronchoalveolar lavage (BAL) in 24 patients with sarcoidosis (8), lung fibrosis (9), primary lung cancer (7), and we compared expression of Fas in BALF cells from all groups and healthy volunteers (6). Fas protein was detected by immunocytochemistry using APAAP technique with an LSAB 2 kit (Dako). Positive reactions for Fas were found in the cytoplasm of epithelial cells, macrophages, neutrophils and lymphocytes (according to the intensity). There were some differences in proportion of positive cells and intensity of reaction between patients with interstitial lung diseases, healthy volunteers as well as patients with lung cancer. Higher expression of Fas in alveolar macrophages was observed in patients with sarcoidosis, lower in patients with lung cancer, lung fibrosis and the lowest in healthy persons. The analysis of Fas antigen expression in the BALF cells may be useful in evaluation of the role of apoptosis in lung homeostasis and pathology.