Steroids Inhibit Eosinophil Accumulation and Downregulate Hematopoietic Chemotaxic Prostaglandin D2 Receptor in Aspirin-Exacerbated Respiratory Disease.

Abstract

Aspirin-exacerbated respiratory disease (AERD) is characterized by eosinophilic rhinosinusitis, nasal polyposis, aspirin sensitivity, and asthma. Aims/Objectives: This study aims to identify a mechanism to target for the future treatment of AERD via the elucidation of the effect of systemic steroids on the expression of hematopoietic prostaglandin D2 synthase (HPGDS) and chemotaxic prostaglandin D2 (DP2) receptor relative to eosinophil activation in the nasal polyps of patients with AERD. Among 37 patients undergoing endoscopic sinus surgery, 28 received systemic steroids preoperatively. Nasal polyps were harvested from all 37 patients. After routine processing of paraffin sections, immunohistochemistry was performed using specific antibodies for HPGDS, eosinophil peroxidase (EPX), and DP2. Expression of HPGDS, DP2, and EPX by eosinophils was higher and more frequent in patients with non-preoperative steroid therapy. Likewise, HPGDS and DP2 were highly expressed in activated eosinophils in the nasal polyps, but not in normal eosinophils. This study provides clear evidence that systemic steroid therapy inhibits eosinophil activation and decreases HPGDS and DP2 expression in patients with AERD, indicating a reduction in prostaglandin D2 production and hence control hyperplasia of nasal polyps.