Immune interferon is a growth factor for human lung fibroblasts.

A number of immunologically mediated lung disorders are characterized by the presence of fibrosis. In these studies, we demonstrate that immune (gamma) interferon, as well as interleukin-1 (IL-1), can function as a growth factor for human lung fibroblasts. Interleukin-2 has no effect on the proliferation of these cells. Interferon increases the proliferation of lung fibroblasts in a dose-dependent manner and functions as a progression factor by complementing the growth-promoting effects of a characterized competence factor such as fibroblast growth factor. These observations suggest that interferon, as well as IL-1, may play an important role in the fibrotic response as well as the immune response in the lung.