Expression of the transforming growth factor beta isoforms in inflammatorycells of nasal polyps

Objective: To determine the expression and the potential role of transformi ng growth factor beta (TGF-beta) in nasal polyposis. Design: Comparison of TGF-beta expression between normal and inflammatory n asal mucosa and polyps; in inflammatory nasal polyps, characterization of t he TGF-beta isoforms expression and their potential location in macrophages and eosinophils. Setting: Patients and samples were selected at the Hopital Intercommunal, C reteil, France, and immunohistochemistry and immunoblots were performed at the Institut National de la Sante et de la Recherche Medicale U296 (Univers ite Paris XII, France). Subjects: Nasal polyps and nasal mucosa were sampled in 21 patients during ethmoidectomy, and muscosa was sampled in 6 healthy patients during rhinopl asty. Methods: Immunohistochemistry and Western blot analysis were performed usin g specific antibodies to TGF-beta(1-3), TGF-beta(1), TGF-beta(2), and TGF-b eta(3) isoforms. Double labeling was also performed using anti-TGF-beta(1) antibody together with macrophages or eosinophil-specific antibodies. Results: The expression of TGF-beta(1-3) was significantly higher in inflam matory nasal polyps than in inflammatory nasal mucosa and higher in inflamm atory nasal mucosa than in nasal mucosa from healthy patients. Transforming growth factor beta(1) was the main isoform detected in inflammatory nasal polyps, and it was present in numerous macrophages and in some eosinophils. Conclusions: Transforming growth factor beta, mainly TGF-beta(1), is strong ly expressed in inflammatory nasal mucosa, where it could be produced by ma crophages and eosinophils. Transforming growth factor beta could induce epi thelium and connective tissue modifications and therefore be involved in th e pathogenesis of nasal polyposis.