Studies on the pathogenesis of interstitial pneumonia of collagen vascular diseases Part 1. Cellulae responses of interstitial pneumonia of collagen vascular diseases by bronchoalveolar lavage

Various pulmonary involvements have been reported in collagen vascular diseases (CVD). Interstitial pneumonia (IP) is one of the common complications. The pathogenesis of IP is still obscure. In this study bronchoalveolar lavage (BAL) was applied to analyze the cellular response in the pathological changes in the bronchioloalveolar regions in IP of CVD such as RA, SLE, polymyositis/dermatomyositis and PSS. Increased total cell counts and cellular density in the BAL fluid were shown in most of the CVD with IP. Furthermore, a relative decrease in the percetn of macrophages and increase in the percent of lymphocytes, neutrophils, eosinophils and basophil/mast cells in BALL fluid were revealed, the increase being more marked in active IP than in non-active IP. T-cell subsetes of lymphocytes in the BALL fluid were analyzed with flow cytometry. A decrease in the CD4/CD8 ratio was shown in most of the IP with CVD except for RA in which the CD4/CD8 ratio was increased. Total cell count and percentage of macrophage was higher in the smoking group than in the non-smoking group of IP with RA. These findings indicate that cellular responses obtained by BAL could be useful not only for analyzing the pathogenesis of IP of CVD but also for evaluating the disease activity of IP.