EXPRESSION AND LOCALIZATION OF TUMOR-NECROSIS-FACTOR-ALPHA AND ITS MESSENGER-RNA IN IDIOPATHIC PULMONARY FIBROSIS

The expression of tumor necrosis factor a and its mRNA was investigate d in surgical biopsies from idiopathic pulmonary fibrosis by immunohis tochemistry, in situ hybridization, and Northern blotting. Normal area s of lungs resected for cancer were used as controls. Tumor necrosis f actor a mRNA levels were higher in idiopathic pulmonary fibrosis than in normal lungs as determined by Northern blots. In normal lungs, tumo r necrosis factor a and its mRNA were identified in alveolar and inter stitial macrophages. In fibrotic lungs, tumor necrosis factor alpha wa s detected in macrophages and, to a greater extent, in epithelial cell s (presumably type II cells) Using the thickened septae. Tumor necrosi s factor a mRNA was found only in some interstitial cells and some of the cells lining the alveolar septae. An elevated concentration of tum or necrosis factor = alpha, particularly within the alveolar epitheliu m, might contribute to the alveolar damage and proliferation of inters titial cells in idiopathic pulmonary fibrosis.