Comparison of Arachidonic Acid Metabolism in Nasal Polyps and Eosinophils

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Abstract
Nasal polyp tissue is characterized by its frequent infiltration by large numbers of eosinophils. We have studied the metabolism of 14C-labeled arachidonic acid by both nasal polyp tissue and by eosinophils. The major metabolite produced by both is 15-hydroxyeicosatetraenoic acid (HETE) with lesser amounts of 12-HETE. No cyclooxygenase pathway products were found. The 15-lipoxygenase activity of nasal polyps averages 30 times that of normal nasal mucosa or chronically inflamed sinus mucosa. Nasal polyps which contained significant numbers of eosinophils averaged 7 times the 15-lipoxygenase activity of nasal polyps without eosinophilia. Thus, eosinophils appear to be a major source of 15-lipoxygenase activity in nasal polyps.