Released intranasal eosinophilic major basic protein as a diagnostic marker for polypoid chronic rhinosinusitis

OBJECTIVE: To investigate the hypothesis that eosinophil major basic protein is released in high concentrations in the nasal mucus of patients with polypoid chronic rhinosinusitis. STUDY DESIGN: Single center, open, prospective trial. SETTING: Medical University of Graz, Austria. SUBJECTS AND METHODS: Patients with polypoid chronic rhinosinusitis (n = 23) were compared to three different control groups: patients with chronic rhinosinusitis-like symptoms but without general mucosal thickening, patients who underwent functional endoscopic sinus surgery for reasons other than chronic rhinosinusitis, and patients without sinus disease (total n = 21). Mucus was harvested from each patient using a standardized technique and analyzed for eosinophil major basic protein with an enzyme-linked immunosorbent assay. RESULTS: In the patient group with polypoid chronic rhinosinusitis, 20 of 23 (87%) were positive for eosinophil major basic protein. In contrast, only one control patient was positive, whereas the remainder had no detectable amount of eosinophil major basic protein in the mucus (P < 0.001 vs chronic rhinosinusitis). CONCLUSION: Toxic eosinophil major basic protein levels are elevated in polypoid chronic rhinosinusitis patients compared to control groups that have similar clinical presentations but upon closer examination turn out not to have chronic rhinosinusitis. In the future, the detection of eosinophil major basic protein in nasal mucus may become a sensitive and specific marker for chronic rhinosinusitis and a helpful diagnostic tool. (C) 2010 American Academy of Otolaryngology Head and Neck Surgery Foundation. All rights reserved.