Role of IgE Low-Affinity Receptor (CD23) in Pathogenesis of Nasal Polyp

Background: Nasal polyps, a common clinical problem, are characterized by eosinophilic and mast cell inflammation.  The role of allergy and IgE in pathogenesis of nasal polyps is still unclear.  IgE receptors are important components of the immunological pathway in allergic and inflammatory diseases. Objective: To determine if the low affinity IgE receptor (CD23) is presented on nasal polyp tissues as a marker of local allergy or inflammation. Methods: Twenty patients who had undergone polypectomy enrolled into the study.  Polyp tissues were stained by hematoxylin-eosin and acid-fast methods for histopathologic study.  Immunohistochemical staining was performed with monoclonal antibody to leukocyte surface CD23.  Polyp tissue fluid was extracted by slicing and centrifuging.  Total serum IgE and tissue fluid was measured by ELISA. Results: Thirteen of 20 polyp tissues were positive for CD23.  Moderate to large number of eosinophils were observed in 5 patients. Serum IgE level was elevated (>70 IU /ml) in 13 patients and polyp IgE level was elevated in 8 patients.  No significant correlation was found between CD23, serum and polyp tissue IgE, and eosinophil infiltration. Conclusion: CD23 may act as non-IgE dependent inflammatory marker in the pathogenesis of nasal polyps.