Phenotypic and functional characteristics of IL-21-expressing CD8+ T cells in human nasal polyps

Abstract

Although CD4+ T cells are recognized to play an important role in the inflammatory response of nasal polyps (NPs), the biological functions of CD8+ T cells in polypogenesis remain unclear. In this study, we analyzed cell markers, cytokine expression and transcription factors in IL-21-expressing CD8+ T cells in polyp tissues of NP patients. The results showed that the majority of IL-21-producing CD8+ T cells were effector memory cells and they co-expressed IFN-γ. IL-21-expressing CD8+ T cells in polyp tissues expressed higher CXCR5, PD-1, and ICOS levels than cells in control tissues and showed significantly higher T-bet and Bcl-6 expression levels compared with IL-21−CD8+ T cells. Purified polyp CD8+ T cells promoted IgG production from isolated polyp B cells in vitro, and recombinant IL-12 modulated the expression of IL-21, IFN-γ and CD40L in purified polyp CD8+ T cells. Moreover, the percentage of IL-21+CD8+ T cells in polyp tissues was positively correlated with endoscopic and CT scan scores in NP patients. These findings indicated that polyp CD8+ T cells, by co-expressing IL-21 and IFN-γ and other markers, display a Tfh cell functionality, which is associated with the clinical severity of NP patients.

Frequency of CD4+ and CD8+ T cells in Iranian chronic rhinosinusitis patients

“…Chronic rhinosinusitis (CRS) is an inflammatory condition affecting the sinonasal mucosa and T lymphocytes are important cells in the pathogenesis of CRS [ 25 ]. It is the first study conducted on the pattern of CD4 + and CD8 + T cells in Iranian CRS patients.…”

Distinct expression of NK2 homeobox 1 (NKX2‐1) and goblet cell hyperplasia in nasal polyps with different endotypes

“…All the stained sections were examined by light microscopy using an Aperio imagscope microscope (Leica). Specifically, the immunofluorescence assay was performed as described …”

CXCR5+ CD8 T Cells: Protective or Pathogenic?

“…Murine autoimmune CXCR5+PD-1 hi CD8 T cells expressing CD40L and GL-7 promote antibody responses (29). CXCR5+ CD8 T cells in human nasal polyps that localize to B cells promote inflammatory damage (35). Together, these data reveal a pattern of CXCR5+ CD8 T cell homing related to antigen accumulation and the site of local immunological responses (Figure 3C).…”

“…Human tonsil CD8 T cells co-cultured with B cells promoted B cell survival like that of CXCR5+ CD4 T cells and induced IgG class-switching (20). IL-21-producing CD8 T cells from human nasal polyps co-express IFNγ and IL-21 to induce B cell class-switch to IgG when co-cultured with B cells (35). IFNγ is a known mediator of B class-switch to IgG2a/c, yet CXCR5+ CD8 T cells that arise in spontaneous autoimmune disease induced B cell class-switch to predominately IgG1.…”