Background: Local tissue production of antigen-specific immunoglobulin E (IgE) has been shown in patients with allergic rhinitis and in patients with chronic rhinosinusitis (CRS) with nasal polyps. In allergic fungal rhinosinusitis (AFRS), specific IgE has been established in nasal lavage fluid and eosinophilic mucin. In this study, local production of antigen-specific IgE within sinus mucosa of AFRS patients was evaluated.
Methods: Sinus mucosa homogenates from 11 AFRS patients, 8 patients with CRS without nasal polyps (CRSsNP), and 9 nonrhinosinusitis control patients were assessed for IgE localization by immunohistochemistry. AFRS and control tissue homogenates were also evaluated for antigen-specific IgE to 14 common antigens by ImmunoCAP testing (Phadia AB, Portage, MI).
Results: There was a significant increase in IgE staining in AFRS sinus epithelium and subepithelium compared with controls and with patients with CRSsNP (p <or= 0.012 for all group differences). AFRS patients showed increased IgE staining in the subepithelium when compared with epithelium (p < 0.001). AFRS sinus tissue had significantly more IgE measured by ImmunoCAP when compared with control sinus tissue for 7 of 14 specific antigens (p < 0.05) and for total IgE (p = 0.004). Antigens with a significant difference on ImmunoCAP included Cladosporium, Aspergillus, Timothy grass, red maple, cockroach, ragweed, and cocklebur.
Conclusion: AFRS patients showed significantly more IgE in sinus mucosa tissue specimens, with increased IgE in subepithelial sites when compared with epithelium. The increased expression of antigen-specific IgE is not limited to fungal antigens. These findings support the role of type I hypersensitivity and local manifestations of allergy in AFRS patients.