Characterization of T-cell subpopulations in patients with chronic rhinosinusitis with nasal polyposis

BACKGROUND: There is an ongoing discussion concerning the potential origins of chronic rhinosinusitis with nasal polyposis (CRSwNP). OBJECTIVE: The aim of this study was to quantify subpopulations of T cells in peripheral blood and nasal polyps in CRSwNP to examine their influence on the etiology of this disease. METHODS: Tissue and blood samples were collected from 11 patients who underwent nasal sinus surgery, and these samples were analyzed by multicolor flow cytometry. RESULTS: There was a significantly lower frequency of CD4(+) T-helper (Th) cells and a significantly higher frequency of CD8(+) T cells among lymphocytes isolated from nasal polyps compared with peripheral blood mononuclear cells (PBMC). In both T-cell subpopulations, a shift mainly from naive T cells among peripheral blood lymphocytes toward an effector memory and terminally differentiated subtype predominance in nasal polyps was observed. Among CD4(+) T cells, the frequencies of cluster of differentiation (CD) 45RA- Forkhead-Box-Protein P3high (FoxP3(high)) cytotoxic T-lymphocyte-associated Protein 4high (CTLA-4(high)) activated regulatory T (T(reg)) cells, and CD45RA- Forkhead-Box-Protein P3low (FoxP3(low)) memory T cells were significantly increased in nasal polyps compared with PBMC. CONCLUSION: In this study, we presented a detailed characterization of CD4(+) and CD8(+) T-cell subpopulations in patients with CRSwNP. CD8(+) T cells were more prominent in nasal polyps than in CD4(+) T cells. Both nasal CD8(+) T cells and CD4(+) T cells predominantly had an effector memory phenotype. Among CD4(+) T cells, activated T(reg) cells were increased in nasal polyps compared with PBMC. The data point toward a local regulation of T-cell composition within the microenvironment of nasal polyps, which might be further exploited in the future to develop novel immunotherapeutic strategies.