Cysteinyl leukotriene 1 receptor expression in nasal polyps

The pathogenesis of nasal polyps, thought to involve complex interactions between different factors, is currently not fully understood. Recent studies have suggested the involvement of cysteinyl leukotrienes (CysLTs) in nasal polyp development. To further understand the role of CysLTs in polyp pathogenesis, we studied the expression of CysLT1 receptors in nasal polyps.

The study group comprised polyps removed endoscopically from 20 consecutive patients. Samples of ethmoid mucosa from 4 patients who underwent orbital decompression for Graves' ophthalmopathy were used as controls. The presence of CysLT1 receptors was determined with a rabbit anti-human anti-CysLT1 receptor polyclonal antibody. Cells with and without CysLT1 receptor expression were counted within the epithelial layer and stroma by means of light microscopy (40x magnification).

There were significantly more cells expressing CysLT1 receptors in the stroma than in the epithelium in both nasal polyps and control specimens. The stroma of polyps also contained more CysLT1 receptor-expressing cells than did controls (29 x 10(3) +/- 7 x 10(3) versus 3 x 10(3) +/- 3 x 10(3) cells per square millimeter; p < .01). In the epithelium of polyps, there was significantly higher expression of CysLT1 receptors than in controls (7 x 10(3) + 3 x 10(3) versus 0 cells per square millimeter; p = .02). No significant differences in polyps were found between patients with and patients without Samter's triad and asthma.

The significant up-regulation of CysLT1 receptors we found in both the stroma and the epithelium of nasal polyps suggests the presence of an inflammatory component in the pathogenesis of polyps, and possibly explains the efficacy of leukotriene modifiers in their treatment.