[Studies on the pathogenesis of lung fibrosis by bronchoalveolar lavage and Ga scintigraphy]

The pathogenesis of lung fibrosis in patients with idiopathic interstitial pneumonia (IIP) and other interstitial pneumonia was studied with bronchoalveolar lavage (BAL) and gallium (Ga) scintigraphy. Patients with interstitial pneumonia showed increased populations of lymphocytes, neutrophils and basophils (mast cells) in BAL fluids especially in patients is the active stage of interstitial pneumonia. Fibronectin concentration in BAL fluids of patients with interstitial pneumonia was higher than those of normal control. These fibronectin levels in BAL fluids were shown to correlate with the density of total cell, macrophage and neutrophil in each BAL fluid. Enhanced fibronectin synthesis by alveolar macrophages in vitro was observed in patients with IIP in comparison with that of normal control. Increased Ga radioactivity was shown in BAL fluids of patients with interstitial pneumonia right after the Ga scintigraphy. The Ga index (Ga in BAL fluid/Ga in peripheral blood) correlated with the density of total cell and macrophage in BAL fluid. These data indicate that the accumulation of activated alveolar macrophages and neutrophils could play an important role in the pathogenesis of lung fibrosis in patients with interstitial pneumonia.