EXPRESSION OF 3 MEMBERS OF THE TNF-R FAMILY OF RECEPTORS (4-1BB, LYMPHOTOXIN-BETA RECEPTOR, AND FAS) IN HUMAN LUNG

Receptors belonging to the tumour necrosis factor receptor (TNF-R) sup erfamily are implicated in a variety of important biological processes . Although messenger ribonucleic acid coding for many of these recepto rs has been detected in lung, little is known about their expression i n this organ. In this study, immunohistochemical techniques were used to evaluate the expression of three receptors of this family (4-1BB, l ymphotoxin-beta receptor (LT beta-R), and Fas) in normal human lung, l ung carcinomas and by tuberculous and sarcoid granulomas. The 4-1BB re ceptor was uniformly expressed by endothelial cells of small vessels a nd by basal epithelial cells within pseudostratified bronchial epithel ium. LTP-R expression by parenchymal cells was limited to those of epi thelial origin (bronchial and bronchiolar epithelium, hyperplastic alv eolar epithelium and lung carcinomas). Fas was present on both fibrobl asts and epithelial cells (bronchial and alveolar epithelium and most, but not all, carcinomas), but not on endothelial cells. A subpopulati on of T-lymphocytes expressed these receptors, but only Fas was detect ed on normal alveolar macrophages and epithelioid cells. Thus, 4-1BB, LT beta-R, and Fas have characteristic and only partially overlapping patterns of expression in the lung. The findings should facilitate fur ther evaluation of their role in lung homeostasis and pathology.