Is Allergic Fungal Sinusitis A Distinct Form Of Chronic Rhinosinusitis?

RATIONALE: Controversy exists as to whether allergic fungal sinusitis (AFS) constitutes a distinct form of chronic rhinosinusitis (CRS). We attempted to determine if the immune response to fungi would differentiate AFS from other forms of CRS. METHODS: Eighty four CRS patients with nasal polyps were enrolled in this IRB approved study after nasosinus surgery. Recovered exudates were cultured and examined by histology for eosinophils, Charcot-Leyden crystals, and fungal elements. Serum total IgE and IgG anti-alternaria (IgG-A) antibodies were determined by UniCAP 100. Immunoblotting for IgE anti-alternaria, aspergillus, bipolaris, curvularia, epicoccum, fusarium and phoma was performed with sera from 15 patients. RESULTS: Exudates from 66 patients contained large numbers of eosinophils. Many also had Charcot-Leyden crystals and fungal hyphae. If fungal hyphae were absent, fungal cultures were positive. These patients were designated as AFS, with the remaining 18 patients as CRS. Both serum total IgE and IgG-A were statistically significantly elevated in the AFS group compared to CRS. Total IgE (IU/ml) means (ranges) were AFS=1080 IU/ml (28-12,230) and CRS=324 (8.8-1081); IgG-A (mg/l) means were AFS=40.6 mg/l (0-182) and CRS=8.2 (2-37.7). Immunoblotting for IgE anti-fungi showed multiple bands to all fungi in 9/10 AFS patients, whereas 0/5 CRS patients showed IgE to all fungi. The number of positive bands for each fungus were statistically significantly increased in AFS vs CRS. CONCLUSION: AFS patients demonstrate a markedly enhanced IgE and IgG immune response to fungi. This clearly differentiates them from other forms of CRS.