Studis on the pathogenesis of idiopathic interstitial pneumonia Part 1. Analysis of local cellular response in lungs by bronchoalveolar lavage of patients with idiopathic interstitial pneumonia

The cellular components in lungs of idiopathic interstitial pneumonia (IIP) and interstitial pneumonia with collagen disease (IP with CD) were examined by bronchoalveolar lavage (BAL) to analyze the pathogenesis of IIP. The findings of BAL fluid of IIP and IP with CD were increase of total cell count and increased percent of lymphocytes, neutrophils, eosinophils and basophil/mast cells in comparison with the normal control. The BAL fluid of the patients with IIP and IP with CD in active stage contained a higher proportion of lymphocyte, neutrophil, eosinophil and basophil/mast cell than those in a nonactive stage. Furthermore, an increase of T-cells and Ia positive T-cells was detected in the examination of lymphocyte subpopulation in BAL fluid of patients with IIP, while the lymphocyte subpopulation of peripheral blood showed no significant difference. Cellular components in BAL fluid of IIP patients treated with or without steroids were compared. Under steroid therapy a decrease of total cell count and eosinophil was shown in BAL fluids of patients with IIP. These findings indicate that various cells such as macrophage, lymphocyte, neutrophil eosinophil and basophil/mast cell in lungs play important roles in the pathogenesis of IIP and IP with CD.