Accumulation of CD69+ tissue-resident memory T cells in the nasal polyps of patients with chronic rhinosinusitis

Abstract

In patients with chronic rhinosinusitis with nasal polyps (CRSwNP), a relative accumulation of cluster of differentiation (CD)8+ T cells over CD4+ T cells occurs in nasal polyps compared with the peripheral blood. Nasal CD 8+ T cells and CD 4+ T cells predominantly present an effector memory phenotype. Immunological studies have reported that memory T cells recirculate from the tissues to the peripheral blood and a high percentage of these T cells persist within the tissue. The aim of the present study was to characterize CD 69+ sphingosine-1-phosphate receptor 1 (S1PR1)- tissue resident memory T cells (Trm) in the polyps of patients with CRSwNP. Tissue and blood samples were collected from 10 patients undergoing nasal sinus surgery. Expression of specific extraand intracellular molecules were analyzed using multicolor flow cytometry. A significantly higher level of CD8+ T cells than CD 4+ T cells was present in nasal polyps, while significantly more CD 4+ T cells than CD 8+ T cells were detected in the peripheral blood of patients with CRSwNP. The frequency of CD69+ T cells was significantly higher in CD8+ and CD 4+ T cells in nasal polyps compared with the peripheral blood. The frequency of CD 69+ S1PR1- Trm was also significantly higher in CD 4+ and CD 8+ T cells from nasal polyps compared with the peripheral blood. Within polyps, the frequency of CD 69+ S1PR1- Trm was again significantly higher in CD8+ compared with CD 4+ T cells. In summary, a significantly higher frequency of CD69+ S1PR1- T cells was observed in the nasal polyps compared with the peripheral blood in patients with CRSwNP. The results of the present study suggest that local regulation of the immune response occurs within nasal polyps. As such, Trm should be considered a potential stimulus in the pathogenesis of nasal polyps. However, the role of Trm in nasal polyps as a pathogenic trigger of the local inflammatory reaction requires further investigation.