Guan-Ting Zhai

Ectopic lymphoid tissues support local immunoglobulin production in patients with chronic rhinosinusitis with nasal polyps

Background: The contribution of ectopic lymphoid tissues (eLTs) to local immunoglobulin hyperproduction in patients with chronic rhinosinusitis with nasal polyps (CRSwNP) is unclear. Objective: We sought to explore the cellular basis, formation mechanisms, and function of eLTs in patients with CRSwNP. Methods: We graded lymphoid aggregations in sinonasal mucosa and histologically studied their structures. The expression of lymphorganogenic factors and molecules required for immunoglobulin production was measured by using real‐time PCR, and their localization was analyzed by means of immunohistochemistry and immunofluorescence. The phenotype of follicular helper T cells was analyzed by performing flow cytometry. Immunoglobulin levels were quantified by using the Bio‐Plex assay or ImmunoCAP system. Nasal tissue explants were challenged ex vivo with Dermatophagoides pteronyssinus group 1 (Der p 1), and the expression of I&egr;‐C&mgr; and I&egr;‐C&ggr; circle transcripts was detected by using seminested PCR. Results: Increased formation of eLTs with germinal center–like structures was discovered in patients with eosinophilic (20.69%) and noneosinophilic (17.31%) CRSwNP compared with that in patients with chronic rhinosinusitis without nasal polyps (5.66%) and control subjects (3.70%). The presence of eLTs was associated with increased expression of lymphorganogenic and inflammatory chemokines and cytokines, as well as their receptors. The expression of molecules required for immunoglobulin production, generation of follicular helper T cells, and production of IgE in eosinophilic polyps and IgG and IgA in both eosinophilic and noneosinophilic polyps were predominantly upregulated in patients with eLTs. After Der p 1 challenge ex vivo, I&egr;‐C&mgr; transcript was detected only in eosinophilic polyps with eLTs but not in polyps without eLTs and noneosinophilic polyps. Conclusion: eLTs might support local immunoglobulin production and therefore significantly contribute to the development of CRSwNP.

The activation and function of IL-36γ in neutrophilic inflammation in chronic rhinosinusitis

Background Although increased accumulation of neutrophils has been noted in chronic rhinosinusitis (CRS), the function and regulation of neutrophils in CRS are largely unknown. IL‐36 family cytokines may play an important role in neutrophilic inflammation. Objective This study sought to investigate the expression and function of IL‐36 cytokines in CRS. Methods Quantitative RT‐PCR, immunohistochemistry, immunofluorescence, and ELISA were used to investigate the expression of IL‐36 cytokines and IL‐36 receptor (IL‐36R) in sinonasal mucosa. The expression of IL‐36R on neutrophils in polyps and blood was measured by flow cytometry. Purified blood neutrophils were cultured to investigate the regulation of IL‐36R expression. The cleavage of IL‐36&ggr; was detected by Western blotting. Dispersed nasal polyp cells were treated with IL‐36&ggr; with or without elastase inhibitor and dexamethasone. Results Neutrophil infiltration and expression of IL‐36 cytokines and IL‐36R were upregulated in both CRS with and without nasal polyps. IL‐36&ggr; was the most abundant isoform and mainly expressed by epithelial cells in CRS. Neutrophils were the principal IL‐36R+ cell type in polyps. IL‐36R expression was almost absent in blood neutrophils and upregulated by IL‐6, IL‐1&bgr;, and Dermatophagoides pteronyssinus group 1. Elastase activity was increased in polyps and degraded full‐length IL‐36&ggr;. Consistently, the levels of cleaved IL‐36&ggr; were increased in polyps. Full‐length IL‐36&ggr; promoted the production of matrix metalloproteinase 9; IL‐17A; and chemokine (C‐X‐C motif) ligands 1, 2, and 8 from dispersed nasal polyp cells, which was abolished by elastase inhibitor. The proinflammatory effect of IL‐36&ggr; was not suppressed by dexamethasone. Conclusions Increased production and activation of IL‐36&ggr; may act on neutrophils and further exaggerate neutrophilic inflammation in CRS.

IgD-activated mast cells induce IgE synthesis in B cells in nasal polyps

Background: Although upregulated expression of local IgD has been reported in patients with chronic rhinosinusitis (CRS), its function is unclear. Objective: We sought to explore the expression and function of soluble IgD in patients with CRS, particularly CRS with nasal polyps. Methods: IgD levels in sinonasal mucosa were analyzed by using RT‐PCR and ELISA. Numbers and phenotypes of IgD+ cells were studied by means of immunohistochemistry, immunofluorescence, and flow cytometry. HMC‐1 cells, a human mast cell line, and mast cells purified from eosinophilic polyps were cultured alone or with naive B cells purified from peripheral blood. The antigen specificity of nasal IgD was investigated by using ELISA. Results: The mRNA expression of immunoglobulin heavy constant delta gene, numbers of IgD+ cells, and protein levels of secretory IgD in sinonasal mucosa were increased in patients with CRS with or without nasal polyps compared with control subjects. Numbers of IgD+ plasmablasts were increased in both eosinophilic and noneosinophilic polyps, whereas numbers of IgD+ mast cells were only increased in eosinophilic polyps. Cross‐linking IgD induced serum preincubated HMC‐1 cells and polyp mast cells to produce B‐cell activating factor, IL‐21, IL‐4, and IL‐13 and to promote IgM, IgG, IgA, and IgE production from B cells. In eosinophilic polyps expression of those B cell–stimulating factors in mast cells and close contact between mast cells and B cells were found. Moreover, positive correlations of total IgD levels with total IgE levels and eosinophilia and upregulation of specific IgD against house dust mites were discovered in eosinophilic polyps. Conclusion: IgD‐activated mast cells can facilitate IgE production and eosinophilic inflammation in patients with CRS with nasal polyps.