Group 2 innate lymphoid cells are elevated and activated in chronic rhinosinusitis with nasal polyps

Background

Chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP) is characterized by type 2 inflammation with high levels of Th2 cytokines. Although T helper cytokines are released from T cells, innate lymphoid cells (ILC) are also known to produce high levels of the same cytokines. However, the presence of various types of ILC in CRS is poorly understood.

Objective

The objective of this study was to fully characterize the presence of all ILC subsets in CRS and to identify phenotypical differences of group 2 ILC (ILC2) in CRSwNP compared to ILC2 from non‐type 2 inflamed areas.

Methods

We investigated the presence of ILC subsets in peripheral blood mononuclear cells (PBMC) from healthy subjects, tonsil tissue, ethmoid tissue from control subjects and patients with non‐polypoid CRS (CRSsNP) and CRSwNP, as well as nasal polyp (NP) tissue from CRSwNP by flow cytometry. Sorted ILC2 were cultured in the presence and absence of IL‐33 and production of IL‐5 and IL‐13 was assessed by Luminex.

Results

We found that all ILC subsets were present in NP but ILC2 were dominant and significantly elevated compared to PBMC, tonsil, CRSsNP, and normal sinus tissue. We also found that inducible T‐cell co‐stimulator (ICOS) and side scatter were increased and CD127 was down‐regulated in ILC2 from NP compared to blood or tonsil ILC2. Thymic stromal lymphopoietin, IL‐7, and IL‐33 were able to down‐regulate expression of CD127 and increase side scatter in blood ILC2. Furthermore, sorted NP ILC2 but not blood ILC2 spontaneously released type 2 cytokines including IL‐5 and IL‐13.

Conclusions and Clinical Relevance

These results suggest that ILC2 are not only elevated but also activated in CRSwNP in vivo and that ILC2 may play important roles in the type 2 inflammation in CRSwNP.

Chronic airway inflammation provides a unique environment for B cell activation and antibody production

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 (NPs), which are characterized by type 2 inflammation, eosinophils and group 2 innate lymphoid cells (ILC2s). 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 analysed B cells from NP or tonsil, or after ILC2 coculture, 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 extrafollicular marker Epstein-Barr virus-induced protein 2 (EBI2), but significantly fewer germinal centre (GC) B cells compared with 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.

Superior turbinate eosinophilia correlates with olfactory deficit in chronic rhinosinusitis patients

OBJECTIVE

To evaluate if molecular markers of eosinophilia in olfactory-enriched mucosa are associated with olfactory dysfunction.

STUDY DESIGN

Cross-sectional study of tissue biopsies from 99 patients, and an additional 30 patients who underwent prospective olfactory testing prior to sinonasal procedures.

METHODS

Tissue biopsies were processed for analysis of inflammatory markers using quantitative real time polymerase chain reaction (qRT-PCR). Ipsilateral olfactory performance was assessed using the Sniffin' Sticks (Burghart, Wedel, Germany) threshold component and the University of Pennsylvania Smell Identification Test (Sensonics, Haddon Heights, NJ). Age-adjusted data was correlated with inflammatory marker expression and clinical measures of obstruction from computed tomography and endoscopy.

RESULTS

Gene expression of the eosinophil marker CLC (Charcot Leyden crystal protein) was elevated in superior turbinate (ST) tissue in chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP) compared to ST and inferior turbinate tissue in CRS without nasal polyps (CRSsNP) and control patients (all P < 0.001, respectively). CLC in ST tissue was correlated with IL-5 and eotaxin-1 expression (all P < 0.001; P = 0.65, and 0.49, respectively). CLC expression was strongly correlated with eosinophilic cationic protein levels (P < 0.001; r = -0.76), and ST CLC expression was inversely related to olfactory threshold (P = 0.002, r = -0.57) and discrimination scores (P = 0.05, r = -0.42). In multiple linear regression of CLC gene expression, polyp status, and radiographic and endoscopic findings with olfactory threshold, CLC was the only significantly correlated variable (P < 0.05).

CONCLUSION

Markers of eosinophils are elevated in the ST of patients with CRSwNP and correlate with olfactory loss. These findings support the hypothesis that olfactory dysfunction in CRS correlates local eosinophil influx into the olfactory cleft.

LEVEL OF EVIDENCE

NA. Laryngoscope, 127:2210-2218, 2017.

Clinical Characteristics of Patients with Chronic Rhinosinusitis with Nasal Polyps, Asthma, and Aspirin-Exacerbated Respiratory Disease

BACKGROUND

Aspirin-exacerbated respiratory disease (AERD) comprises the triad of chronic rhinosinusitis with nasal polyps (CRSwNP), asthma, and intolerance to inhibitors of the cyclooxygenase-1 (COX-1) enzyme. The prevalence of AERD remains unclear, and few studies have compared the clinical characteristics of patients with AERD to those with CRSwNP alone, asthma alone, or both CRSwNP and asthma.

OBJECTIVE

To determine the prevalence of AERD within a tertiary care setting, and to identify unique clinical features that could distinguish these patients from those with both CRSwNP and asthma or with CRSwNP alone.

METHODS

Electronic medical records of patients at Northwestern in Chicago, Illinois, were searched by computer algorithm and then manual chart review to identify 459 patients with CRSwNP alone, 412 with both CRSwNP and asthma, 171 with AERD, and 300 with asthma only. Demographic and clinical features including sex, atopy, and sinus disease severity were characterized.

RESULTS

The prevalence of AERD among patients with CRSwNP was 16%. Patients with AERD had undergone 2-fold more sinus surgeries (P < .001) and were significantly younger at the time of their first surgery (40 ± 13 years) than were patients with CRSwNP (43 ± 14 years; P < .05). Atopy was significantly more prevalent in patients with AERD (84%) or asthma (85%) than in patients with CRSwNP (66%, P < .05). More patients with AERD (13%) had corticosteroid-dependent disease than patients with both CRSwNP and asthma (4%, P < .01) or asthma (1%, P < .001).

CONCLUSIONS

AERD is common among patients with CRSwNP; even though patients with AERD have CRSwNP and asthma, the clinical course of their disease is not the same as of patients who have CRSwNP and asthma but are tolerant to COX-1 inhibitors.

Discordant frequencies of tissue-resident and circulating CD180-negative B cells in chronic rhinosinusitis

BACKGROUND

The unconventional toll-like receptor (TLR) CD180 is implicated in chronic inflammatory diseases; however, its role in chronic rhinosinusitis (CRS) has yet to be investigated. Here we study the expression of CD180, its homologue TLR4 and myeloid differentiation factor 1 (MD1) on mucosal and systemic immune cell populations in relation to serum immunoglobulin G (IgG) levels.

METHODS

A total of 70 patients were recruited to the study. Mucosal and peripheral blood samples were prospectively collected from CRS patients and non-CRS controls without evidence of sinus disease. The expression of TLR4, MD1, and CD180 was investigated using qualitative real-time polymerase chain reaction (qRT-PCR), immunohistochemistry, and flow cytometry. Serum IgG levels were determined using enzyme-linked immunosorbent assay (ELISA).

RESULTS

CRS with nasal polyps (CRSwNP) patients had significantly increased messenger RNA (mRNA) expression of CD180 and MD1 compared to controls (5.54-fold and 2.1-fold, respectively, p < 0.01). B cells lacking CD180 were lower in CRSwNP tissue compared to CRS without nasal polyps (CRSsNP) and controls (21.07 ± 6.41 vs 41.61 ± 7.82 vs 40.06 ± 8.06; p < 0.01) but higher in blood (39.18 ± 8.3 vs 17.95 ± 7.82 and 12.49 ± 4.92; p ≤ 0.05).

CONCLUSION

Changes in mucosal and peripheral CD180-expressing B cells were identified in CRSwNP patients compared to CRSsNP and controls. This suggests a role for these cells in the dysregulated immune response in these patients.

Heterogeneous inflammatory patterns in chronic rhinosinusitis without nasal polyps in Chicago, Illinois

CRSsNP is a heterogenous disease but type 2 inflammation in CRSsNP was more common than type 1 inflammation among patients in Chicago, Illinois. Distinct therapeutic strategies may be needed depending on the type of inflammation found in CRSsNP.

Proton pump inhibitors decrease eotaxin-3/CCL26 expression in patients with chronic rhinosinusitis with nasal polyps: Possible role of the nongastric H,K-ATPase

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) is often characterized by tissue eosinophilia that is associated with poor prognosis. Recent findings that proton pump inhibitors (PPIs) directly modulate the expression of eotaxin-3, an eosinophil chemoattractant, in patients with eosinophilic diseases suggest therapeutic potential for PPIs in those with CRSwNP.

OBJECTIVE

We assessed the effect of type 2 mediators, particularly IL-13 and eotaxin-3, on tissue eosinophilia and disease severity in patients with chronic rhinosinusitis (CRS). Further investigation focused on PPI suppression of eotaxin-3 expression in vivo and in vitro, with exploration of underlying mechanisms.

METHODS

Type 2 mediator levels in nasal tissues and secretions were measured by using a multiplex immunoassay. Eotaxin-3 and other chemokines expressed in IL-13-stimulated human sinonasal epithelial cells (HNECs) and BEAS-2B cells with or without PPIs were assessed by using ELISA, Western blotting, real-time PCR, and intracellular pH imaging.

RESULTS

Nasal tissues and secretions from patients with CRSwNP had increased IL-13, eotaxin-2, and eotaxin-3 levels, and these were positively correlated with tissue eosinophil cationic protein levels and radiographic scores in patients with CRS (P < .05). IL-13 stimulation of HNECs and BEAS-2B cells dominantly induced eotaxin-3 expression, which was significantly inhibited by PPIs (P < .05). Patients with CRS taking PPIs also showed lower in vivo eotaxin-3 levels compared with those without PPIs (P < .05). Using intracellular pH imaging and altering extracellular K⁺, we found that IL-13 enhanced H⁺,K⁺-exchange, which was blocked by PPIs and the mechanistically unrelated H,K-ATPase inhibitor, SCH-28080. Furthermore, knockdown of ATP12A (gene for the nongastric H,K-ATPase) significantly attenuated IL-13-induced eotaxin-3 expression in HNECs. PPIs also had effects on accelerating IL-13-induced eotaxin-3 mRNA decay.

CONCLUSION

Our results demonstrated that PPIs reduce IL-13-induced eotaxin-3 expression by airway epithelial cells. Furthermore, mechanistic studies suggest that the nongastric H,K-ATPase is necessary for IL-13-mediated epithelial responses, and its inhibitors, including PPIs, might be of therapeutic value in patients with CRSwNP by reducing epithelial production of eotaxin-3.

B-Cells and Antibody-Mediated Pathogenesis in Chronic Rhinosinusitis with Nasal Polyps

The sinonasal mucosa forms a dynamic immune barrier where epithelial cells and the immune system interact with the inhaled environment and nasal microbiome. Recent studies suggest that B-cells, plasma cells and antibody production are highly activated locally within the nasal mucosa of patients with chronic rhinosinusitis with nasal polyps (CRSwNP). Findings additionally suggest that polyp tissue contains elevated levels of cytokines, chemokines and complement that may drive this profound B-cell response. Currently, the data are conflicting on whether the B-cell response found in the CRSwNP nasal mucosa is antigen-specific, a superantigen response or an expansion of natural antibody responses. Indeed, investigations into the specificity of the mucosal antibody responses find increased production of class-switched antibodies that bind to aeroallergens, staphylococcus aureus as well as autoantigens. A continuation of these studies is needed to elucidate whether extrinsic factors, like the inhaled environment, or intrinsic factors, like the mucosal microbiome and host inflammatory response, are key to the pathogenesis of CRSwNP. This chapter will cover the current evidence regarding local B-cell responses in CRSwNP.

Regulation of B cell responses in allergy by histamine receptors

Histamine is a bioactive amine stored in mast cells and basophils and released upon antigen-specific IgE-dependent activation, mediating responses during allergic reactivity, including vasodilation, smooth muscle constriction and inflammatory cell recruitment. These are regulated through four receptors (H1R-H4R) that are differentially expressed on various cell types. Despite this, increasing evidence suggests that histamine can be produced during the priming phase of allergen responses, with H4R on dendritic cells being important for initiating Type 2 immunity. Here, we sought to determine the roles of these receptors in supporting antigen-specific B cell responses. Interestingly, our data demonstrates that both murine and human B cells only expressed H1R and H2R; these also showed differential expression levels on specific B cell subsets and upon activation. Using an Ovalbumin-alum (OVA-alum) model of allergic immunization, mice lacking H2R produced significantly lower levels of OVA-IgE, whereas mice lacking H1R were unaffected. Surprisingly, absence of both H1R and H2R (H1R/H2R DKO) exhibited undetectable levels of OVA-IgE. This was not due to T cell-intrinsic influences since restimulation of splenocytes from immunized H1R/H2R DKO mice showed that Th2 cytokine production was unaltered compared to WT. Instead, in vitro stimulation of B220+ B cells by αCD40 and IL-4 yielded significantly lower IgE production from H1R/H2R DKO mice than WT and defines a key requirement for these receptors in permitting B cells from generating IgE antibodies. Our data establishes a novel requirement for histamine, a molecule typically considered in regulating allergic responses, in supporting the generation of allergic sensitivity.

Proprotein convertases generate a highly functional heterodimeric form of thymic stromal lymphopoietin in chronic rhinosinusitis

Thymic stromal lymphopoietin (TSLP) is known to be elevated and truncated in nasal polyps (NPs) of chronic rhinosinusitis and might play a significant role in type 2 inflammation in this disease. However, neither the structure nor the role of the truncated products of TSLP has been studied. We investigated the mechanisms of truncation of TSLP in NPs and the function of the truncated products. We incubated recombinant full-length 15.1 KDa human TSLP (methionine + residues 29–159, referred to as M29–159) with NP extracts. SDS-PAGE revealed two major truncated products of TSLP in NP extracts. Edman sequencing and MALDI-TOF MS results indicated that the longer truncation product was TSLP (M29–124) and the smaller product was TSLP (131–159). We found that PCSK (proprotein convertase subtilisin/kexin) family proteases were rate-limiting enzymes in the truncation and generation of TSLP (M29–130) and TSLP (131–159). Carboxypeptidases further digested 6 amino acids from the C-terminus of TSLP (M29–130) to generate TSLP (M29–124) in NPs. Interestingly, recombinant TSLP (M29–124) and TSLP (131–159) did not manifest TSLP activity, but PCSK-digested TSLP had significantly higher activity than full-length TSLP on myeloid dendritic cells and group 2 innate lymphoid cells. Finally, we identified a 14.2 KDa TSLP from incubation of TSLP with NP extracts under non-reducing conditions that was significantly reduced in the presence of DTT. This indicates that the two cleaved products are dimerized with disulfide bonds and the dimerized form, TSLP (29–124 + 131–159), is an active metabolite and may contribute to the amplification of type 2 inflammation in NPs.

Analysis of cytokine production by peanut-reactive T cells identifies residual Th2 effectors in highly allergic children who received peanut oral immunotherapy

BACKGROUND

Only limited evidence is available regarding the cytokine repertoire of effector T cells associated with peanut allergy, and how these responses relate to IgE antibodies to peanut components.

OBJECTIVE

To interrogate T cell effector cytokine populations induced by Ara h 1 and Ara h 2 among peanut allergic (PA) children in the context of IgE and to evaluate their modulation during oral immunotherapy (OIT).

METHODS

Peanut-reactive effector T cells were analysed in conjunction with specific IgE profiles in PA children using intracellular staining and multiplex assay. Cytokine-expressing T cell subpopulations were visualized using SPICE.

RESULTS

Ara h 2 dominated the antibody response to peanut as judged by prevalence and quantity among a cohort of children with IgE to peanut. High IgE (> 15 kU(A)/L) was almost exclusively associated with dual sensitization to Ara h 1 and Ara h 2 and was age independent. Among PA children, IL-4-biased responses to both major allergens were induced, regardless of whether IgE antibodies to Ara h 1 were present. Among subjects receiving OIT in whom high IgE was maintained, Th2 reactivity to peanut components persisted despite clinical desensitization and modulation of allergen-specific immune parameters including augmented specific IgG4 antibodies, Th1 skewing and enhanced IL-10. The complexity of cytokine-positive subpopulations within peanut-reactive IL-4(+) and IFN-γ(+) T cells was similar to that observed in those who received no OIT, but was modified with extended therapy. Nonetheless, high Foxp3 expression was a distinguishing feature of peanut-reactive IL-4(+) T cells irrespective of OIT, and a correlate of their ability to secrete type 2 cytokines.

CONCLUSION

Although total numbers of peanut-reactive IL-4(+) and IFN-γ(+) T cells are modulated by OIT in highly allergic children, complex T cell populations with pathogenic potential persist in the presence of recognized immune markers of successful immunotherapy.

Age-related increased prevalence of asthma and nasal polyps in chronic rhinosinusitis and its association with altered IL-6 trans-signaling

We report that S100 proteins were reduced in patients with chronic rhinosinusitis (CRS). S100A8/9, which is important in epithelial barrier function, was particularly decreased in elderly patients with CRS. Epithelial expression of S100A8/9 is partly regulated by the IL-6 trans-signaling pathway. The goal of this study was to investigate whether or not age-related reduction of S100A8/9 in CRS is associated with blunting of IL-6 trans-signaling. The levels of IL-6, soluble IL-6 receptor (sIL-6R), soluble gp130 (sgp130), and S100A8/9 from control subjects (n = 10), and patients with CRS without nasal polyps (n = 13) and those with CRS with nasal polyps (CRSwNP) (n = 14), were measured by ELISA. Age-related differences in the level of each protein were investigated. Normal human bronchial epithelial cells were cultured in air-liquid interface and stimulated with IL-6/sIL-6R and tumor necrosis factor (TNF)-α with or without the addition of sgp130, a natural inhibitor of IL-6 trans-signaling. There was a significant age-related decline in S100A8/9 and an increase in sgp130 in nasal tissue samples from patients with CRSwNP, although there was no age-related difference in IL-6/sIL-6R production. Additionally, expression of the S100A8/9 gene and protein was increased significantly by IL-6/sIL-6R plus TNF-α in normal human bronchial epithelial cells. This increase was blocked by sgp130. These results suggest that increased sgp130 in older patients may inhibit IL-6 trans-signaling, impair barrier function, and decrease S1008/9 production in elderly patients with CRSwNP. Restoration of barrier function by targeting sgp130 may be a novel treatment strategy.

Immune Mechanisms of Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) is a common inflammatory disease that results in a significant decrease in patient quality of life and a large economic burden. However, the lack of population-based epidemiologic studies and robust model systems has made it difficult to fully elucidate the key inflammatory pathways that drive the chronic inflammatory responses observed in CRS. This review will highlight the wide variety of factors that likely contribute to CRS disease pathogenesis. Defects in the innate immune function of the airway epithelium, including decreases in barrier function, mucociliary clearance, and production of antimicrobial peptides, all likely play a role in the initial inflammatory response. Subsequent recruitment and activation of eosinophils, mast cells, and innate lymphoid cells (ILCs) further contributes to the chronic inflammatory response and directly activates adaptive immune cells, including T and B cells. However, development of new tools and model systems is still needed to further understand the chronicity of this inflammatory response and which specific factors are necessary or sufficient to drive CRS pathogenesis. Such studies will be critical for the development of improved therapeutic strategies aimed at treating this highly prevalent and costly disease.

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.