The Alveolitis of Pulmonary Sarcoidosis

Current concepts of the pathogenesis of pulmonary sarcoidosis suggest that a mononuclear cell alveolitis, comprised of activated T-lymphocytes and activated alveolar macrophages, precedes and modulates the formation of granuloma and fibrosis that characterize the disease. To evaluate the natural history of this alveolitis and determine the relationship it has to subsequent changes in lung function, 19 untreated patients with pulmonary sarcoidosis without extrapulmonary manifestations were studied at 6-month intervals over 10.1 ±1.6 months with bronchoalveolar lavage, 67Ga scanning, and pulmonary function tests to evaluate lung T-cells, lung alveolar macrophages, and lung function, respectively. In this group of patients with sarcoidosis, low intensity alveolitis (lung T-cells ⩽ 28% of all lung effector cells and/or 67Ga scan negative) was much more common (80% of all observations) than high intensity alveolitis (lung T-cells > 28% and 67Ga scan positive, 20% of all observations). However, the alveolitis c...