Aspergillus fumigatus-Specific T Cells in Patients with Chronic Rhinosinusitis.

INTRODUCTION: Aspergillus fumigatus belongs to the saprophytic fungi, and its spores form a significant part of the daily load of fungal spores inhaled as particles in aerosols. A. fumigatus is a possible T-cell activator. Its contribution to the pathogenesis of chronic rhinosinusitis (CRS) is controversially discussed. The aim of this study was to detect and characterize A. fumigatus-specific CD4+ and CD8+ T cells in patients with CRS with (CRSwNP) and without (CRSsNP) nasal polyps.

METHODS: Tissue and blood samples were collected from patients who underwent paranasal sinus surgery due to CRSwNP or CRSsNP. Afterward, purified CD4+ and CD8+ cells were cultured together with antigen-presenting cells. A peptide mix derived from A. fumigatus antigen was added to the cultures. After 6 days, multicolor flow cytometry was performed, and proliferation was measured using the marker Ki-67. Cytokine secretion was quantified from the supernatant of the cell culture.

RESULTS: Significant differences in the proliferation of nasal CD4+ T cells to A. fumigatus antigen were observed for cells from patients with CRSwNP in comparison to CRSsNP, while no differences were found between nasal and peripheral blood T cells. The activation of tissue-derived CD4+ T cells was associated with significantly higher concentrations of IL-4, IL-5, and IL-17a in the cell culture from patients with CRSwNP in comparison to CRSsNP and/or healthy controls.

CONCLUSION: Our findings indicate that patients with CRSwNP harbor a higher proportion of A. fumigatus-reactive CD4+ T cells in the nasal mucosa than patients with CRSsNP. A. fumigatus-reactive CD4+ T cells of CRSwNP patients secreted TH2 cytokines and IL-17. Our findings suggest a role for A. fumigatus in the pathogenesis of CRSwNP and provide a rationale for targeted therapies.