Accumulation of interferon gamma-producing TH1 helper T cells in nasal polyps.

We investigated the mechanisms involved in the formation of nasal polyps by examining T-cell clones and their production of soluble mediators in nasal polyps. Recently, the allergic origin of nasal polyps has been challenged. To study this question we characterized T cells from polyp tissue of allergic individuals in terms of their cytokine pattern. Nasal polyp T cells were cloned from allergic individuals undergoing polypectomy. Polyp tissue was dispersed enzymatically, and T cells were stimulated with mitogen and interleukin-2. Control T cells were obtained from peripheral blood of nonallergic donors. Cytokine production of interleukin-4 and interferon was then determined by indirect enzyme-linked immunosorbent assay tests. Polyp T-cell clones were found to produce high interferon but low interleukin-4 levels that were not significantly different from control peripheral blood T-cell clones. In addition, immunoglobulin production by dispersed polyp tissue was investigated. Immunoglobulin levels were higher in polyp tissues than in serum with immunoglobulin A predominating. These results suggest that the inflammatory reaction in nasal polyps is different than that seen in a typical type I hypersensitivity response.