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Polyps from patients with chronic rhinosinusitis with nasal polyps (CRSwNP) contain increased levels of autoreactive antibodies, B cells and fibrin deposition. Anti-phospholipid antibodies (APA) are autoantibodies known to cause thrombosis but have not been implicated in chronic rhinosinusitis (CRS).To compare APA levels (anti-cardiolipin, anti-phosphatidylethanolamine (anti-PE), and anti-βPatient specimens were assayed for APA IgG, anti-dsDNA IgG and thrombin-anti-thrombin (TaT) complex by ELISA. Antibodies from a subset of specimens were tested for modified activated partial thromboplastin time (aPTT) measured on an optical-mechanical coagulometer.Anti-cardiolipin IgG in NP was 5-fold higher than control tissue (p .0001). NP antibodies prolonged aPTT compared to control tissue antibodies at 400 µg/mL (36.7 s vs. 33.8 s, p = .024) and 600 µg/mL (40.9 s vs. 34.7 s, p = .0037). Anti-PE IgG antibodies were increased in NP (p = .027), but anti-B2GP IgG was not significantly higher (p = .084). All APAs correlated with anti-dsDNA IgG levels, which were also elevated (R = .77, .71 and .54, respectively, for anti-cardiolipin, anti-PE, and anti-B2GP; all p .001), but only anti-cardiolipin (R = .50, p = .0185) and anti-PE (R = 0.45, p = .037) correlated with TaT complex levels.APA IgG antibodies are increased in NP and correlate with autoreactive tissue antibodies. NP antibodies have in vitro anti-coagulant activity similar to those observed in anti-phospholipid syndrome, suggesting that they may have pro-coagulant effects in polyp tissue.

Background Chronic rhinosinusitis (CRS) is a heterogeneous chronic inflammatory disease generally divided based on the presence or absence of nasal polyps (NPs). One of the features of NPs is excessive fibrin deposition, which is associated with down-regulation of tissue plasminogen activator (t-PA) in NPs. As t-PA is expressed in epithelial cells, and epithelium is readily accessible to topical therapies, identifying compounds that can mediate the induction of t-PA would be a potential new strategy for the treatment of NPs. Objective The objective of this study was to determine whether short-chain fatty acids (SCFAs) can induce t-PA in airway epithelial cells via their known receptors GPR41 and GPR43. Methods We performed immunohistochemistry (IHC) to determine whether receptors for SCFAs, known as G protein-coupled receptor 41/free fatty acid receptor 3 (GPR41/FFAR3) and GPR43/FFAR2, are expressed in nasal tissue. Primary normal human bronchial epithelial (NHBE) cells were stimulated with different concentrations of SCFAs to test induction of t-PA, which was analysed by expression of mRNA and protein. Mediation of responses by SCFA receptors was evaluated by specific receptor gene silencing with siRNA. Results Immunohistochemistry study revealed that airway epithelial cells expressed GPR41 and GPR43. Acetic acid, propionic acid, butyric acid and valeric acid significantly induced t-PA expression from two- to tenfolds. The strongest inducer of t-PA from NHBE cells was propionic acid; cells stimulated with propionic acid released t-PA into the supernatant in its active form. Gene silencing of GPR41 and GPR43 revealed that induction of t-PA by SCFAs was dependent upon both GPR41 and GPR43. Conclusions and clinical relevance Short-chain fatty acids were shown to induce airway epithelial cell expression of t-PA via GPR41 and GPR43. Topical delivery of potent compounds that activate these receptors may have value by reducing fibrin deposition and shrinking nasal polyp growth.

Background B cells play many roles in health and disease. However, little is known about the mechanisms that drive B cell responses in the airways, especially in humans. Chronic rhinosinusitis (CRS) is an inflammatory disease of the upper airways that affects 10% of Europeans and Americans. A subset of CRS patients develop nasal polyps (NP), which are characterized by type 2 inflammation, eosinophils and group 2 innate lymphoid cells (ILC2). We have reported that NP contain elevated levels of B cells and antibodies, making NP an ideal system for studying B cells in the airways. Objective We sought to determine the mechanisms that drive B cell activation and antibody production during chronic airway inflammation. Methods We analyzed B cells from NP or tonsil, or after ILC2 co-culture, by flow cytometry. Antibody production from tissue was measured using Luminex assays, and the frequency of antibody-secreting cells by ELISpot. Formation of B cell clusters was assessed using immunohistochemistry. Expression of genes associated with B cell activation and class switch recombination was measured by qRT-PCR. Results NP contained significantly elevated frequencies of plasmablasts, especially those that expressed the extra follicular marker Epstein-Barr virus-induced protein 2 (EBI2), but significantly fewer germinal center (GC) B cells compared to tonsil. Antibody production and the frequency of antibody-secreting cells were significantly elevated in NP, and there was evidence for local class switch recombination in NP. Finally, ILC2s directly induced EBI2 expression on B cells in vitro. Conclusions and Clinical Relevance Our data suggest there is a unique B cell activation environment within NP that is distinct from classic GC-mediated mechanisms. We show for the first time that ILC2s directly induce EBI2 expression on B cells, indicating that ILC2s may play an important role in B cell responses. B cell-targeted therapies may provide new treatment options for CRSwNP. This article is protected by copyright. All rights reserved.