Expression of mast cell surface antigen-1 (MASA-1) on mast cells in bronchoalvelar lavage fluid

Abstract

We reported that a novel protein, mast cell surface antigen-1 (MASA-1), was expressed specifically on human mast cells in the lung lesional tissues of chronic inflammatory diseases such as bronchiolitis obliterans organizing pneumonia (BOOP) and sarcoidosis. In this study, we investigated the expression of MASA-1 on mast cells by immunofluorescence method in bronchoalveolar lavage fluid (BALF) obtained from patients with respiratory diseases (n=72). Levels of SCF and TGF-β1 were measured by ELISA. MASA-1 was found to be expressed in mast cells in patients with BOOP, interstitial pneumonia (IP) and sarcoidosis, though it was not expressed in mast cells in BALF obtained from the lung without lesion in patients with lung cancer. The number of MASA-1 positive cells was significantly increased in patients with chronic inflammatory diseases such as BOOP and IP compared to patients with acute pneumonia and bronchiolitis. Moreover, levels of TGF-β1 and SCF in BOOP and IP were higher than in acute pneumonia and bronchiolitis. There were good correlations between the number of MASA-1 positive cells and levels of TGF-β1 and SCF (r=0.82, r=0.83). These results suggest that human MASA-1 is specifically expressed in mast cells in BALF of chronic inflammatory diseases and that its expression is induced by inflammatory cytokines. MASA-1 should be a marker for activated mast cells in chronic respiratory diseases. [Jpn J Physiol 54 Suppl:S250 (2004)]