Interferon and Growth Factor Activity for Human Lung Fibroblasts: Release from Bronchoalveolar Cells from Patients with Active Sarcoidosis

Abstract

Pulmonary sarcoidosis is a granulomatous disorder of unknown etiology characterized by both an active cellular immune process and interstitial fibrosis. It has recently been demonstrated that gamma-interferon (the type of interferon associated with an active cellular immune process) is also a potent growth factor for human lung fibroblasts. To evaluate the hypothesis that there is an association between the release of immune interferon and the release of growth factor activity for fibroblasts, bronchoalveolar cells from patients with sarcoidosis were studied for the spontaneous release of both immune interferon and growth factor activity for fibroblasts. Bronchoalveolar cells from 11 of the 24 patients spontaneously released gamma-interferon in vitro. Supernatants from sarcoidosis patients whose bronchoalveolar cells released interferon contained a significantly higher percentage of lymphocytes than those whose bronchoalveolar cell supernatants did not contain interferon (p less than 0.01). Fibroblast growth was also significantly augmented by supernatants from sarcoidosis patients whose bronchoalveolar cells released gamma-interferon compared to supernatants which did not contain interferon (p less than 0.05). In patients with focal abnormalities on chest x-ray films, there was significantly more interferon released by bronchoalveolar cells from the areas that were most abnormal compared to more normal areas of the lung. These studies suggest that there is an association between the release of immune interferon and release of growth factor activity for fibroblasts by bronchoalveolar cells from patients with active pulmonary sarcoidosis.