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Background Chronic rhinosinusitis with nasal polyps (CRSwNP) is often characterized by local production of polyclonal IgE-idiotypes. Whilst tissue IgE concentrations can be in the range of several thousand kU/L, the regulatory mechanisms by which IgE-mediated inflammation is controlled in the nasal polyps is not well understood. Objective We sought to determine whether locally induced IgG antibodies in the nasal polyps can inhibit IgE-mediated pro-allergic response. Methods Nasal polyp homogenates were collected from grass pollen allergics with CRSwNP and non-allergic controls. IgE levels were measured by ISAC. IgE-containing nasal polyp homogenates, with/without IgG depletion, were evaluated for their capacity to promote IgE-facilitated allergen presentation, basophil activation and histamine release. Local IgE and IgG repertoires were evaluated by Immunoglobulin 454 sequencing. Results We show that IgG plays a key role in controlling IgE-mediated inflammatory responses in nasal polyps. Depletion of IgG from nasal homogenates resulted in an increase in CD23-mediated IgE-facilitated allergen binding to B cells (IgE-FAB), but also enhanced FcεRI-mediated allergen driven basophil activation and histamine release. A similar response was observed in relation to specific IgE antibodies to Staphylococcus aureus (SE-IgE). The capacity of IgG in nasal polyps to limit IgE-mediated inflammation is based on the fact that IgG repertoires widely share the antigen targets with the IgE repertoires, in both allergic and non-allergic subjects. Conclusion Polyclonal IgE idiotypes in CRSwNP are functional, promote IgE-mediated pro-allergic inflammation and are partially antagonized by corresponding IgG-idiotypes. This is most likely due to the fact that IgE and IgG clonotypes are widely shared in nasal polyps.

Background: Chronic rhinosinusitis with nasal polyposis (CRSwNP) is an inflammatory disease associated with lymphoid aggregates and local IgE production related to Staphylococcus aureus enterotoxins. T-follicular helper cells and their effector cytokine interleukin (IL)-21 play an important role in germinal center proliferation. Methods: IL-21 was determined on the mRNA level by qPCR in nasal tissue of 3 groups of patients: control (n = 17), chronic rhinosinusitis without nasal polyposis (CRSsNP; n = 23), and CRSwNP (n = 35). The expression of IL-21 by CD4+ T cells was analyzed in tissue at baseline and after 24-h stimulation of tissue fragments with S. aureus enterotoxin B (SEB) using flow cytometry. Finally, human nasal IL-21+CXCR5+CD4+ T cells were isolated and coincubated with human blood naive B cells to investigate their functionality. Results: IL-21 mRNA expression was increased in the CRSwNP group (p < 0.05) compared to the control group, and B-cell lymphoma-6 and B-lymphocyte-induced maturation protein-1 were upregulated in CRSwNP versus CRSsNP. Furthermore, SEB was able to increase IL-21 mRNA expression significantly (p < 0.01) in nasal polyps. Flow cytometry revealed that the source of IL-21 was predominantly CD4+ T cells and that IL-21+CD4+ T cells were significantly increased in polyp tissue and further increased after SEB stimulation. Finally, tissue CXCR5+CD4+ T cells derived from nasal polyp tissue were able to induce maturation of human naive B cells. Conclusions: IL-21- and IL-21-producing CD4+ T cells were increased in CRSwNP. In addition, SEB induced an increase in IL-21 and IL-21+CD4+ T cells, suggesting that S. aureus can modulate the function of Tfh cells in nasal polyps. We speculate that T-follicular helper cells and IL-21 are important in the pathophysiology of CRSwNP.

Background: We aimed to elucidate possible differences in antiviral defense in chronic rhinosinusitis with nasal polyps (CRSwNP) mucosal tissue compared to healthy mucosal tissue (HMT) upon herpes simplex virus 1 (HSV1) exposure. Methodology: HMT and CRSwNP samples were infected with HSV1. We visualized the virus location by immunofluorescence and monitored invasion by a score. The mediators Interferon (IFN)-α, IFN-β, IFN-λ, IFN-γ, Interleukin (IL)-6, IL-1β, Tumor necrosis factor (TNF)-α, IL-17, IL-5, IL-10 were measured in culture supernatants at baseline and at 24h, 48h and 72h after virus incubation. Results: CRSwNP mucosal tissue showed a significant deficit in IFN-γ and IL-17 release within 24 to 72 hours after infection in comparison to HMT, at the same time releasing significantly more pro-inflammatory cytokines including IL-1β and TNF-α. These findings were associated with significantly higher viral invasion scores at 48 and 72 h in CRSwNP mucosa compared to those for the HMT. Conclusions: We demonstrate for the first time in a human ex-vivo mucosal model that the inadequate response of CRSwNP may be associated with a deeper intrusion of viruses into the mucosal tissue, and may contribute to more and longer symptoms upon acute infection, but also to the persistence of inflammation in CRSwNP tissue. © 2016, AMC. All rights reserved.

Chronic rhinosinusitis with nasal polyps (CRSwNP) is characterized by biased Th2 inflammation and CRS without nasal polyps (CRSsNP) by a Th1 immune response. Colonization by Staphylococcus aureus is increased in CRSwNP. We aimed to determine macrophage phenotypes in nasal mucosa of CRSwNP and CRSsNP and to examine phagocytosis of S. aureus in these pathologies.Macrophage phenotyping was performed by immunohistochemical staining on nasal mucosa sections from 28 patients; in addition flow cytometry analysis was performed. Tissue homogenate protein levels of IFN-γ, IL-5, IL-6, IL-1β, TGF-β, eosinophil cationic protein (ECP) and total IgE were analyzed and correlated with macrophage subtypes. Phagocytosis of S. aureus was analyzed by flow cytometry. Survival of S. aureus in Thp1 cells in the presence of polarizing cytokines was studied in vitro. By immunohistochemical analysis more M2 macrophages were present in CRSwNP than in CRSsNP. This also was positively correlated with increased levels of IL-5, ECP and locally produced IgE and decreased levels of IL-6, IL-1β and IFN-γ. FACS analysis of dissociated nasal tissue confirmed the presence of increased numbers of M2 macrophages (CD206(+) HLADR(+) CD14(+) CD11c(+) CD20(-) ) in CRSwNP as compared to controls, while the number of M1 macrophages (CD206(-) HLADR(+) CD14(+) CD11c(int) CD16(-) CD20(-) ) was not different. Phagocytosis of S. aureus by human tissue derived macrophages was reduced in CRSwNP as compared to macrophages from the control inferior turbinates. Decreased phagocytosis of S. aureus and an M2 activation phenotype in CRSwNP could potentially contribute to persistence of chronic inflammation in CRSwNP.