Abnormal secretion of interleukin-1 and tumor necrosis factor alpha by alveolar macrophages in coal worker's pneumoconiosis: comparison between simple pneumoconiosis and progressive massive fibrosis.

The aim of this study was to compare the secretion of tumor necrosis factor alpha (TNF alpha) and interleukin-1 (IL-1) by alveolar macrophages (AMs) harvested from patients with coal worker's pneumoconiosis (CWP) and control subjects. We observed higher levels of spontaneous TNF alpha and IL-1 secretion by AMs from patients with CWP than in those from healthy controls. We did not find any significant difference between the two groups in the incidence of simple pneumoconiosis and progressive massive fibrosis. In the group of coal miners without radiologic signs of pneumoconiosis, we found high levels of both cytokines in a subgroup of subjects still exposed to the mineral dust but not in the subgroup of subjects removed from exposure. These results indicate that AMs are involved in chronic lung inflammatory reactions to mineral dusts, partly by way of cytokine secretion. Moreover, cytokine secretion by AMs appears to be an early event that is detectable at the moment of mineral dust exposure. The results open new perspectives in the study of the mechanisms leading to CWP.