Transforming growth factor-alpha and rhinitis.

Abstract

Transforming growth factor-alpha (TGF-alpha) has been implicated in diverse physiologic and pathophysiologic functions including immunological, inflammatory, and neoplastic processes. TGF-alpha has been localized in the hyperproliferative, inflammatory environment of chronic otitis media, cholesteatoma, and asthmatic airways. TGF-beta1, which must be present with TGF-alpha to transform fibroblasts, has been found in rhinitic mucosa and in asthma in prior studies. The authors sought to identify whether TGF-alpha also played a role in the inflammatory cascade and fibrosis of rhinitis. A nonrandomized, prospective study was carried out in which samples of inferior turbinate and nasal polyps from rhinitic and nonrhinitic patients were subjected to immunohistochemistry and Western blotting to determine the presence of TGF-alpha. Twenty-seven subjects undergoing surgery for rhinitis, obstructive sleep apnea, nasal fracture, and rhinoplasty were recruited for this study, the latter three groups acting as controls. Immunohistochemical and Western blotting techniques were employed to identify the presence of TGF-alpha in inferior-turbinate and nasal-polyp samples of rhinitic subjects. Immunohistochemistry demonstrated the selective staining of TGF-alpha in the basement membrane and extracellular matrix, including lymphatic, vascular, and glandular structures, in most turbinate samples and the absence of staining in corresponding controls. Further, TGF-alpha was isolated to a discrete 30-kD band in both inferior turbinate and polyp tissues by Western blotting without staining in the corresponding controls. These results suggest that TGF-alpha may play a role in the inflammatory derangement of rhinitis.