Etiology of nasal polyps associated with aspirin-sensitive asthma

It is well known that nasal polyps occur at high frequency in aspirin-sensitive asthma (ASA). Their etiology, however, remains obscure. Therefore, histopathologic observations and measurements of arachidonic acid metabolites were carried out to investigate the etiopathogenesis of nasal polyps in ASA. Abundant eosinophils and degranulated mast cells were found in the tissue of nasal polyp-associated ASA cases. Electron-microscopic analyses of these eosinophils revealed that high-electron-dense material had disappeared from the cytoplasmic granules' central crystalloids. Arachidonic acid metabolites (PGE2, PGF2, 6-keto-PGF1 and TXB2) from the cyclooxygenase pathway were measured via gas mass-chromatography. Leukotrienes (LTC4 and LTD4) from the lipoxygenase pathway were measured via HPLC-radioimmunoassay. Especially noteworthy are the high level of leukotrienes and low level of prostaglandins in nasal polyp-associated ASA. The etiopathogenesis of nasal polyps in aspirin-sensitive asthma is postulated.