Transforming growth factor-alpha and rhinitis

Objectives: Transforming growth factor-alpha (TGF-alpha) has been implicate d in diverse physiologic and pathophysiologic functions including immunolog ical, inflammatory, and neoplastic processes. TGF-alpha has been localized in the hyperproliferative, inflammatory environment of chronic otitis media , cholesteatoma, and asthmatic airways. TGF-beta 1, which must be present w ith TGF-alpha to transform fibroblasts, has been found in rhinitic mucosa a nd in asthma in prior studies. The authors sought to identify whether TGF-a lpha also played a role in the inflammatory cascade and fibrosis of rhiniti s. Study Design: A nonrandomized, prospective study was carried out in whic h samples of inferior turbinate and nasal polyps from rhinitic and nonrhini tic patients were subjected to immunohistochemistry and Western blotting to determine the presence of TGF-alpha. Methods: Twenty-seven subjects underg oing surgery for rhinitis, obstructive sleep apnea, nasal fracture, and rhi noplasty were recruited for this study, the latter three groups acting as c ontrols. Immunohistochemical and Western blotting techniques were employed to identify the presence of TGF-alpha in inferior-turbinate and nasal-polyp samples of rhinitic subjects. Results: Immunohistochemistry demonstrated t he selective staining of TGF-alpha in the basement membrane and extracellul ar matrix, including lymphatic, vascular, and glandular structures, in most turbinate samples and the absence of staining in corresponding controls. F urther, TGF-alpha was isolated to a discrete 30-kD band in both inferior tu rbinate and polyp tissues by Western blotting without staining in the corre sponding controls. Conclusions: These results suggest that TGF-alpha may pl ay a role in the inflammatory derangement of rhinitis.