Role of local immunoglobulin E specific for Alternaria alternata in the pathogenesis of nasal polyposis

OBJECTIVE/HYPOTHESIS: The role of fungal pathogens in the etiology of nasal polyposis remains unclear. The aim of this study was to determine whether there was a correlation between the presence of Alternaria-specific immunoglobulin (Ig)E antibodies, eosinophilic inflammation, and the development of nasal polyps. STUDY DESIGN: Prospective study. METHODS: Serum and nasal tissue homogenates from 21 patients with manifestations of chronic sinusitis with nasal polyps were compared with specimens from 13 chronic sinusitis patients without polyps and 8 healthy controls. The Phadia ImmunoCAP and enzyme-linked immunosorbent assay were used to quantify levels of total IgE and Alternaria-specific (IgE, IgG, and IgA) antibodies. Eosinophil cationic protein (ECP) and tryptase levels were measured in tissue homogenates, whereas the inflammatory response was evaluated using tissue eosinophil counts in tissue samples. RESULTS: Serum analysis revealed no difference in the levels of total IgE and Alternaria-specific IgE, IgG, and IgA antibodies between the study groups. In contrast, the levels of Alternaria-specific IgE in tissue with polyps were significantly higher than in nonpolyp tissue. Increases in total tissue IgE paralleled increased levels of Alternaria-specific IgG and IgA antibodies in chronic sinusitis with nasal polyps as compared with control groups. A positive correlation was found between Alternaria-specific IgE and ECP in tissue. Increased mean levels of ECP corresponded to increased eosinophil counts in the group of patients with polyps. CONCLUSIONS: Alternaria-specific IgE and eosinophilic inflammation in nasal tissue correlates with the incidence of nasal polyps irrespective of specific IgE antibodies in serum. Together, the correlation between the local immune responses and the eosinophilic inflammation in nasal polyps suggests a possible role of Alternaria in the pathogenesis of nasal polyposis.