Untargeted metabolomic profiling identifies disease-specific and outcome-related signatures in chronic rhinosinusitis.

BACKGROUND: Although metabolomics provides novel insights into disease mechanisms and biomarkers, the metabolic alterations in local tissues affected by chronic rhinosinusitis (CRS) are unknown. OBJECTIVE: This study aimed to determine the metabolomic profiles of sinonasal tissues associated with different types of CRS and their treatment outcomes. METHODS: Untargeted metabolomic profiling was performed on sinonasal tissues obtained from patients with eosinophilic CRS with nasal polyps (CRSwNP), noneosinophilic CRSwNP or CRS without nasal polyps (CRSsNP), and controls. The messenger RNA (mRNA) levels of inflammatory cytokines in nasal tissues were detected by quantitative real-time reverse transcriptase PCR. Nasal polyp tissues were cultured ex vivo and treated with glutathione. RESULTS: Distinct metabolomic profiles were observed for the CRS subtypes. Eosinophilic CRSwNP had profoundly enhanced unsaturated fatty acid oxidization, which correlated with mucosal eosinophil numbers and IL-5 mRNA levels. Noneosinophilic CRSwNP was characterized by uric acid accumulation. Increased uric acid levels were positively correlated with mucosal neutrophil numbers and IFN-γ, IL-17A, IL-1ß, and IL-8 mRNA levels. Disrupted purine metabolism was specifically detected in CRSsNP. Reduced levels of amino acid metabolites were found in eosinophilic CRSwNP and CRSsNP, and were inversely associated with mucosal total inflammatory cell numbers and inflammatory cytokines. Compared to non-difficult-to-treat CRS, difficult-to-treat CRS had higher glutathione disulfide levels, which were positively correlated with IL-8 mRNA levels. Glutathione treatment reduced IL-8 mRNA expression in cultured nasal polyp tissues. CONCLUSIONS: Specific metabolic signatures are associated with different types of CRS, inflammatory patterns, and disease outcomes, which may provide novel insights into pathophysiologic mechanisms, subtype-specific biomarkers, and treatment targets of CRS.

Evidence for the Presence of Long-Lived Plasma Cells in Nasal Polyps.

PURPOSE: Plasma cells and immunoglobulins (Igs) play a pivotal role in the induction and maintenance of chronic inflammation in nasal polyps. During secondary immune responses, plasma cell survival and Ig production are regulated by the local environment. The purpose of the present study was to investigate the presence of long-lived plasma cells (LLPCs) and specific survival niches for LLPCs in human nasal polyps. METHODS: Nasal mucosal samples were cultured with an air-liquid interface system and the Ig levels in culture supernatants were analyzed by enzyme-linked immunosorbent assay. The characteristics of LLPCs in nasal polyps were determined by immunohistochemistry and immunofluorescence. The expression of neurotrophins as well as their receptors was detected by quantitative real-time polymerase chain reaction, immunohistochemistry, immunofluorescence, and Western blotting. RESULTS: The numbers of CD138⁺ total plasma cells and BCL2⁺ plasma cells were increased in both eosinophilic and non-eosinophilic nasal polyps compared with those in normal tissues. The production of IgG, IgA, and IgE was detected in culture supernatants even after a 32-day culture of nasal polyps. Although the total numbers of plasma cells were decreased in nasal polyps after culture, the numbers of BCL2⁺ plasma cells remained stable. The expression of nerve growth factor (NGF) as well as tropomyosin receptor kinase (Trk) A, a high-affinity receptor for NGF, was upregulated in both eosinophilic and non-eosinophilic nasal polyps. In addition, BCL2⁺ plasma cell numbers were positively correlated with NGF and TrkA mRNA expression in nasal mucosal tissues. Polyp plasma cells had the expression of TrkA. CONCLUSIONS: Human nasal polyps harbor a population of LLPCs and NGF may be involved in their prolonged survival. LLPCs may be a novel therapeutic target for suppressing the local Ig production in nasal polyps.

Increased accumulation of CD30 ligand-positive mast cells associates with eosinophilic inflammation in nasal polyps.

OBJECTIVE: Activation of mast cells associates with eosinophilic inflammation in chronic rhinosinusitis with nasal polyps (CRSwNP). The disease-specific mast cell-triggering mechanisms apart from immunoglobulin E are poorly understood in CRSwNP. CD30L/CD30 are members of the tumor necrosis factor/receptor superfamily and display immune modulatory function on mast cells. The aim of this study was to explore the expression and function of CD30 and CD30L in CRSwNP. METHODS: The mRNA expression of CD30 and CD30L was analyzed by real-time polymerase chain reaction. The cellular expression of CD30L was determined by immunofluorescence staining. The soluble CD30 levels in nasal tissues were detected by enzyme-linked immunosorbent assay. HMC-1 cells, a human mast cell line, were cultured and stimulated with CD30. RESULTS: Compared with control tissues, CD30 mRNA expression levels were increased in eosinophilic polyps, and soluble CD30 protein levels were upregulated in both eosinophilic and noneosinophilic polyps with a greater increase in eosinophilic type. CD30 was expressed by T cells and B cells in nasal polyps. The CD30L mRNA expression levels and the number of CD30L+ cells and CD30L+ tryptase+ mast cells were increased in eosinophilic polyps but not in noneosinophilic polyps as compared with control tissues. Mast cells accounted for 60% of CD30L+ cells in eosinophilic polyps. CD30 induced HMC-1 cells to produce interleukin (IL)-4 and IL-13 without degranulation. Mast cells expressed IL-4 and IL-13 in eosinophilic polyps. The number of CD30L+ tryptase+ mast cells was positively correlated with the number of eosinophils and total inflammatory cells in eosinophilic polyps. CONCLUSION: CD30/CD30L-mediated mast cell activation may promote the eosinophilic inflammation in CRSwNP. LEVEL OF EVIDENCE: NA Laryngoscope, 129:E110-E117, 2019.

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.

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-36γ was detected by Western blotting. Dispersed nasal polyp cells were treated with IL-36γ 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-36γ 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-1ß, and Dermatophagoides pteronyssinus group 1. Elastase activity was increased in polyps and degraded full-length IL-36γ. Consistently, the levels of cleaved IL-36γ were increased in polyps. Full-length IL-36γ 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-36γ was not suppressed by dexamethasone. CONCLUSIONS: Increased production and activation of IL-36γ may act on neutrophils and further exaggerate neutrophilic inflammation in CRS.

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 Iε-Cµ and Iε-Cγ 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, Iε-Cµ 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.

Nasal IL-4(+)CXCR5(+)CD4(+) T follicular helper cell counts correlate with local IgE production in eosinophilic nasal polyps.

BACKGROUND: Locally produced IgE contributes to the initiation and development of eosinophilic inflammation in eosinophilic nasal polyps independent of systemic atopy. However, whether CXCR5(+)CD4(+) T follicular helper (TFH) cells are involved in local IgE production at mucosal sites remains unexplored. OBJECTIVE: We sought to explore the presence, phenotype, and function of CXCR5(+)CD4(+) TFH cells in eosinophilic nasal polyp tissues compared with noneosinophilic nasal polyp and control normal nasal tissues. METHODS: TFH cell-surface phenotypes and subsets and B-cell subsets in nasal tissues and peripheral blood were studied by means of flow cytometry. Immunohistochemistry was used to detect the tissue location of TFH cells. Sorted nasal TFH cells and CXCR5(-) T cells were cultured with autologous naive B cells purified from blood. RESULTS: Nasal TFH cells expressed inducible costimulator, programmed cell death protein 1, and the transcription factor B-cell lymphoma 6 (Bcl-6) at an intermediate level when compared with bona fide TFH cells in tonsils and circulating TFH cells. Although counts of total TFH cells and IL-21(+), IFN-γ(+), and IL-17(+) TFH cells were increased in both eosinophilic and noneosinophilic nasal polyp tissues compared with those in normal nasal tissues, IL-4(+) TFH cell counts were only increased in eosinophilic polyp tissues. IL-4 and IL-21 were involved in polyp TFH cell-induced IgE production from naive B cells, and nasal IL-4(+) TFH cell counts correlated highly with local IgE levels in vivo. IL-4(+)Bcl-6(+)CD4(+) TFH cells were identified in ectopic lymphoid structures in eosinophilic nasal polyps. TFH cells also positively correlated with germinal center B cells and plasma cells in nasal tissues. CONCLUSION: Nasal IL-4(+) TFH cells might be involved in local IgE production in eosinophilic nasal polyps.