Bruce K. Tan

Thymic stromal lymphopoietin activity is increased in nasal polyps of patients with chronic rhinosinusitis

BACKGROUND Chronic rhinosinusitis with nasal polyps (CRSwNP) is associated with TH2-dominant inflammation. Thymic stromal lymphopoietin (TSLP) is a cytokine that triggers dendritic cell-mediated TH2 inflammatory responses and that enhances IL-1-dependent TH2 cytokine production in mast cells. Although increased TSLP mRNA levels have been found in nasal polyps (NPs), expression of TSLP protein and its function in patients with chronic rhinosinusitis (CRS) have not been fully explored. OBJECTIVES The objective of this study was to investigate the role of TSLP in patients with CRS. METHODS We investigated the presence and stability of TSLP protein in NPs using ELISA and Western blotting and investigated the function of TSLP in nasal tissue extracts with a bioassay based on activation of human mast cells. RESULTS Although TSLP mRNA levels were significantly increased in NP tissue from patients with CRSwNP compared with uncinate tissue from patients with CRS or control subjects, TSLP protein was significantly decreased in NP tissue, as detected by using the commercial ELISA kit. We found that recombinant TSLP was time-dependently degraded by NP extracts, and this degradation was completely inhibited by a protease inhibitor cocktail, suggesting that TSLP is sensitive to tissue proteases. Interestingly, NP extract-treated TSLP had higher activity in mast cells, although the amount of full-length TSLP was reduced up to 85%. NP extracts significantly enhanced IL-1β-dependent IL-5 production in mast cells compared with uncinate tissue homogenates, and responses were significantly inhibited by anti-TSLP, suggesting that NPs contain biologically relevant levels of TSLP activity. CONCLUSION TSLP and its metabolic products might play an important role in the inflammation seen in patients with CRSwNP.

Association between severity of asthma and degree of chronic rhinosinusitis.

Background There is a clinical association between asthma and chronic rhinosinusitis (CRS). This study was designed to determine whether severity of coexistent asthma affects the clinical presentation of CRS. Methods Cross-sectional analysis was performed of prospectively collected data in 187 patients with CRS who were evaluated in a large, tertiary academic nasal and sinus center. Patients were stratified into three groups based on asthma status using National Institutes of Health criteria: (1) nonasthmatic, (2) intermittent/mild asthma, (3) or moderate/severe asthma. Results Mean Lund-Mackay scores were 9.7, 11.6, and 15.6, respectively. ANOVA testing with post-hoc Tukey analysis revealed that Lund-MacKay scores were significantly greater in group 3 than either group 1 (p < 0.05) or group 2 (p < 0.01). The prevalence of allergic sensitization was 72.4, 82.8, and 100% in groups 1, 2, and 3, respectively (p = 0.03). The prevalence of nasal polyposis was 31.4% in group 1, 48.3% in group 2, and 94.4% in group 3 (p < 0.0001). No differences were observed regarding demographic factors or the incidence of the triad of aspirin sensitivity, asthma, and nasal polyposis among those with different severities of asthma. Conclusion Increasing severity of asthma is associated with advancing radiological severity of CRS and a greater prevalence of allergic sensitization and nasal polyposis. This large adult series shows that asthma severity may have a significant correlation with the presentation of CRS. This study adds to the growing support for the unified airway theory.

Incidence and associated premorbid diagnoses of patients with chronic rhinosinusitis

BACKGROUND Chronic rhinosinusitis (CRS) is a prevalent condition with underexplored risk factors. OBJECTIVES We sought to determine CRS incidence and evaluate associations with a range of premorbid medical conditions for chronic rhinosinusitis without nasal polyps (CRSsNP) and chronic rhinosinusitis with nasal polyps (CRSwNP) using real-world clinical practice data. METHODS Electronic health records data from 446,480 Geisinger Clinic primary care patients were used for a retrospective longitudinal cohort study for data from 2001-2010. By using logistic regression, newly diagnosed CRS cases between 2007 and 2009 were compared with frequency-matched control subjects on premorbid factors in the immediate (0-6 months), intermediate (7-24 months), and entire observed timeframes before diagnosis. RESULTS The average incidence of CRS was 83 ± 13 CRSwNP cases per 100,000 person-years and 1048 ± 78 CRSsNP cases per 100,000 person-years. Between 2007 and 2009, 595 patients with incident CRSwNP and 7523 patients with incident CRSsNP were identified and compared with 8118 control subjects. Compared with control subjects and patients with CRSsNP, patients with CRSwNP were older and more likely to be male. Before diagnosis, patients with CRS had a higher prevalence of acute rhinosinusitis, allergic rhinitis, chronic rhinitis, asthma, gastroesophageal reflux disease, adenotonsillitis, sleep apnea, anxiety, and headaches (all P < .001). Patients with CRSsNP had a higher premorbid prevalence of infections of the upper and lower airway, skin/soft tissue, and urinary tract (all P < .001). In the immediate and intermediate timeframes analyzed, patients with CRS had more outpatient encounters and antibiotic prescriptions (P < .001), but guideline-recommended diagnostic testing was performed in a minority of cases. CONCLUSIONS Patients who are given a diagnosis of CRS have a higher premorbid prevalence of anxiety, headaches, gastroesophageal reflux disease, sleep apnea, and infections of the respiratory system and some nonrespiratory sites, which results in higher antibiotic, corticosteroid, and health care use. The use of guideline-recommended diagnostic testing for confirmation of CRS remains poor.

Cytokines in Chronic Rhinosinusitis. Role in Eosinophilia and Aspirin-exacerbated Respiratory Disease

RATIONALE The mechanisms that underlie the pathogenesis of chronic rhinosinusitis without nasal polyps (CRSsNP), chronic rhinosinusitis with nasal polyps (CRSwNP), and aspirin-exacerbated respiratory disease (AERD) are not clear. OBJECTIVES To first evaluate the inflammatory profiles of CRSsNP and CRSwNP tissues and then to investigate whether clinical differences observed between CRSwNP and AERD are in part secondary to differences in inflammatory mediator expression within nasal polyp (NP) tissues. METHODS Expression levels of numerous inflammatory mediators were determined by quantitative real-time polymerase chain reaction, ELISA, and multiplex immunoassay. MEASUREMENTS AND MAIN RESULTS CRSwNP NP had increased levels of type 2 mediators, including IL-5 (P < 0.001), IL-13 (P < 0.001), eotaxin-2 (P < 0.001), and monocyte chemoattractant protein (MCP)-4 (P < 0.01), compared with sinonasal tissue from subjects with CRSsNP and control subjects. Expression of IFN-γ messenger RNA or protein was low and not different among the chronic rhinosinusitis subtypes examined. Compared with CRSwNP, AERD NP had elevated protein levels of eosinophil cationic protein (ECP) (P < 0.001), granulocyte-macrophage colony-stimulating factor (GM-CSF) (P < 0.01), and MCP-1 (P = 0.01), as well as decreased gene expression of tissue plasminogen activator (tPA) (P = 0.02). Despite the higher eosinophilia in AERD, there was no associated increase in type 2 mediator protein levels observed. CONCLUSIONS CRSwNP was characterized by a predominant type 2 inflammatory environment, whereas CRSsNP did not reflect a classic type 1 milieu, as has been suggested previously. AERD can be distinguished from CRSwNP by elevated ECP levels, but this enhanced eosinophilia is not associated with elevations in traditional type 2 inflammatory mediators associated with eosinophil proliferation and recruitment. However, other factors, including GM-CSF, MCP-1, and tPA, may be important contributors to AERD pathogenesis.

Perspectives on the etiology of chronic rhinosinusitis.

Purpose of reviewThis article reviews recent insights surrounding the etiology and pathogenesis of chronic rhinosinusitis. In particular, we highlight the increasing recognition of host-mediated mechanisms in driving mucosal inflammation. Recent findingsPublished differences between epithelium from patients with chronic rhinosinusitis and normal controls can be classified into several broad categories. Alterations are reported in the various components of the epithelial innate immune system including epithelial-expressed pattern-recognition receptors (PRRs) and the levels of antimicrobial innate immune effector molecules. Other studies demonstrate differences in the proteins involved in maintaining epithelial barrier integrity. Finally, recent studies show in chronic rhinosinusitis that epithelial-derived cytokines, chemokines and inducible surface proteins are involved in recruiting and activating cells of the adaptive immune system. ConclusionThe sinonasal epithelium provides a mechanical and innate immune barrier to a diverse array of environmental agents. This barrier also plays a key role in regulating the acquired mucosal immune response in the nose. Recent studies suggest that defects in this barrier may foster development of chronic sinonasal inflammation in response to environmental agents, and pathogenic or commensal organisms. The ability to dissect and analyze defects in the inflammatory response in rhinosinusitis may help identify novel targets for drug development.

International Consensus Statement on Allergy and Rhinology: Rhinosinusitis

Isam Alobid, MD, PhD1, Nithin D. Adappa, MD2, Henry P. Barham, MD3, Thiago Bezerra, MD4, Nadieska Caballero, MD5, Eugene G. Chang, MD6, Gaurav Chawdhary, MD7, Philip Chen, MD8, John P. Dahl, MD, PhD9, Anthony Del Signore, MD10, Carrie Flanagan, MD11, Daniel N. Frank, PhD12, Kai Fruth, MD, PhD13, Anne Getz, MD14, Samuel Greig, MD15, Elisa A. Illing, MD16, David W. Jang, MD17, Yong Gi Jung, MD18, Sammy Khalili, MD, MSc19, Cristobal Langdon, MD20, Kent Lam, MD21, Stella Lee, MD22, Seth Lieberman, MD23, Patricia Loftus, MD24, Luis Macias‐Valle, MD25, R. Peter Manes, MD26, Jill Mazza, MD27, Leandra Mfuna, MD28, David Morrissey, MD29, Sue Jean Mun, MD30, Jonathan B. Overdevest, MD, PhD31, Jayant M. Pinto, MD32, Jain Ravi, MD33, Douglas Reh, MD34, Peta L. Sacks, MD35, Michael H. Saste, MD36, John Schneider, MD, MA37, Ahmad R. Sedaghat, MD, PhD38, Zachary M. Soler, MD39, Neville Teo, MD40, Kota Wada, MD41, Kevin Welch, MD42, Troy D. Woodard, MD43, Alan Workman44, Yi Chen Zhao, MD45, David Zopf, MD46

Chronic rhinosinusitis with nasal polyps is characterized by B-cell inflammation and EBV-induced protein 2 expression

BACKGROUND Despite the high prevalence and morbidity of chronic rhinosinusitis (CRS), little is known about the mechanisms that underlie its pathogenesis. Recent studies have suggested that B cells might play an important role in CRS. OBJECTIVE We sought to thoroughly characterize B lineage cells within sinus tissues of patients with CRS and healthy control subjects and to determine whether levels of EBV-induced protein 2, which is known to play an important role in the development of B-cell responses, were increased in patients with CRS. METHODS Cells isolated from sinus tissues of patients with CRS and healthy control subjects were characterized by means of flow cytometry and immunohistochemistry. Local production of antibodies was measured in tissue extracts, nasal lavage fluid, and sera by using multiplex bead arrays and ELISA. Quantitative RT-PCR, ELISA, and Western blotting were used to assess gene and protein expression from tissue extracts. RESULTS Nasal polyps (NPs) from patients with CRS had increased levels of both B cells and plasma cells compared with uncinate tissue from healthy control subjects (P<.05). NPs also contained significantly increased levels of several antibody isotypes compared with normal uncinate tissue (P<.05), but no differences in circulating antibody levels were found. Interestingly, levels of EBV-induced protein 2 were also increased in NPs (P<.05) and were positively correlated with expression of plasma cell markers (CD138 and B lymphocyte-induced maturation protein) in sinus tissue. CONCLUSION B cells and plasma cells are enriched in NPs, actively produce antibodies locally, and might contribute to chronic inflammation in patients with CRS. Elucidating the mechanisms that underlie this excessive local B-cell response might provide novel insights for the development of improved therapeutic strategies.

Reduced expression of antimicrobial PLUNC proteins in nasal polyp tissues of patients with chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a disease characterized by inflammation of the nasal mucosa and paranasal sinuses. This inflammation may result in part from decreased epithelial barrier and innate immune responses, leading to frequent bacterial and fungal colonization. The objectives of this study were to investigate the expression of innate immune proteins of the palate lung and nasal epithelium clone (PLUNC) family in patients with CRS.

Glandular mast cells with distinct phenotype are highly elevated in chronic rhinosinusitis with nasal polyps

BACKGROUND Although chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP) is characterized by T(H)2 inflammation, the role of mast cells is poorly understood. OBJECTIVE The objective of this study was to investigate the presence, localization, and phenotype of mast cells in patients with CRS. METHODS We collected nasal tissue and nasal lavage fluid from patients with CRS and control subjects. We analyzed mRNA for the mast cell proteases tryptase, chymase, and carboxypeptidase A3 by using real-time PCR and measured mast cell protease proteins by using ELISA, immunohistochemistry, and immunofluorescence. RESULTS Tryptase mRNA was significantly increased in nasal polyps (NPs) from patients with CRSwNP (P< .001) compared with uncinate tissue from patients with CRS or control subjects. Tryptase protein was also elevated in NPs and in nasal lavage fluids from patients with CRSwNP. Immnohistochemistry showed increased numbers of mast cells in epithelium and glands but not within the lamina propria in NPs. The mast cells detected in the epithelium in NPs were characterized by the expression of tryptase and carboxypeptidase A3 but not chymase. Mast cells expressing all the 3 proteases were abundant within the glandular epithelium of NPs but were not found in normal glandular structures. CONCLUSIONS Herein we demonstrated a unique localization of mast cells within the glandular epithelium of NPs and showed that mast cells in NPs have distinct phenotypes that vary by tissue location. Glandular mast cells and the diverse subsets of mast cells detected may contribute to the pathogenesis of CRSwNP.

Pathogenesis of nasal polyposis

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a complex inflammatory condition that affects a large proportion of the population world‐wide and is associated with high cost of management and significant morbidity. Yet, there is a lack of population‐based epidemiologic studies using current definitions of CRSwNP, and the mechanisms that drive pathogenesis in this disease remain unclear. In this review, we summarize the current evidence for the plethora of factors that likely contribute to CRSwNP pathogenesis. Defects in the innate function of the airway epithelial barrier, including diminished expression of antimicrobial products and loss of barrier integrity, combined with colonization by fungi and bacteria likely play a critical role in the development of chronic inflammation in CRSwNP. This chronic inflammation is characterized by elevated expression of many key inflammatory cytokines and chemokines, including IL‐5, thymic stromal lymphopoietin and CCL11, that help to initiate and perpetuate this chronic inflammatory response. Together, these factors likely combine to drive the influx of a variety of immune cells, including eosinophils, mast cells, group 2 innate lymphoid cells and lymphocytes, which participate in the chronic inflammatory response within the nasal polyps. Importantly, however, future studies are needed to demonstrate the necessity and sufficiency of these potential drivers of disease in CRSwNP. In addition to the development of new tools and models to aid mechanistic studies, the field of CRSwNP research also needs the type of robust epidemiologic data that has served the asthma community so well. Given the high prevalence, costs and morbidity, there is a great need for continued research into CRS that could facilitate the development of novel therapeutic strategies to improve treatment for patients who suffer from this disease.