Murine model of eosinophilic chronic rhinosinusitis with nasal polyposis inducing neuroinflammation and olfactory dysfunction.

BACKGROUND: Chronic rhinosinusitis (CRS) is a common inflammatory condition affecting the nasal and paranasal sinus mucosa, often accompanied by olfactory dysfunction. Eosinophilic CRS with nasal polyps (ECRSwNP) is a subtype of CRS characterized by eosinophilic infiltration. Animal models for ECRSwNP with olfactory dysfunction are necessary for exploring potential therapeutic strategies. OBJECTIVE: The aim of this study was to establish a mouse model of ECRSwNP combined with olfactory dysfunction in a shorter time frame using intranasal ovalbumin and Aspergillus protease (AP) administration. The efficacy of the model was validated by evaluating sinonasal inflammation, cytokine levels, olfactory function, and neuroinflammation in the olfactory bulb. METHODS: Male BALB/c mice were intranasally administered ovalbumin and AP for 6 and 12 weeks to induce ECRSwNP. The resultant ECRSwNP mouse model underwent histologic assessment, cytokine analysis of nasal lavage fluid, olfactory behavioral tests, and gene expression profiling to identify neuroinflammatory markers within the olfactory bulb. RESULTS: The developed mouse model exhibited substantial eosinophil infiltration, increased levels of inflammatory cytokines in nasal lavage fluid, and confirmed olfactory dysfunction through behavioral assays. Furthermore, olfactory bulb inflammation and reduced mature olfactory sensory neurons were observed in the model. CONCLUSION: This study successfully established a validated mouse model of ECRSwNP with olfactory dysfunction within a remarkably short span of 6 weeks, providing a valuable tool for investigating the pathogenesis and potential therapies for this condition. The model offers an efficient approach for future research in CRS with nasal polyps and olfactory dysfunction.

Residual nasal polyp tissue following dupilumab therapy is associated with periostin-associated fibrosis.

PURPOSE: Dupilumab, an anti-interleukin-4 receptor alpha monoclonal antibody, is a new treatment for severe uncontrolled chronic rhinosinusitis with nasal polyps. However, data on the effect of dupilumab on histological changes in nasal polyp tissue are lacking. We aimed to investigate the effect of dupilumab on real-life clinical conditions and nasal polyp tissues from patients with eosinophilic chronic rhinosinusitis (ECRS), which is a refractory subtype. METHODS: We conducted an open-label, prospective, observational, single-centre study on 63 patients with refractory ECRS on the basis of the criteria of the Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis Study. These patients had a history of surgery and received dupilumab for 24 weeks. Patient-reported sinonasal symptoms, T&T olfactometry and nasal polyp scores were prospectively evaluated. In 23 patients with residual nasal polyps following dupilumab treatment, changes in systemic and local periostin expression, and total collagen deposition in nasal polyp tissues were investigated before and after dupilumab administration. RESULTS: Dupilumab rapidly improved sinonasal symptoms and reduced the nasal polyp score 24 weeks after initiation. 40 (63.5%) patients had resolution of nasal polyps, but the reduction was limited in the remaining 23 (36.5%) patients. Periostin expression in serum and nasal lavage fluid was decreased, whereas periostin and the total collagen deposition area in subepithelial tissues in residual nasal polyps were enhanced after dupilumab administration. CONCLUSION: Dupilumab improves sinonasal symptoms and reduces the nasal polyp score in refractory ECRS. Periostin-associated tissue fibrosis may be involved in the differential effect of dupilumab on nasal polyp reduction.

Common Characteristics of Sinonasal Inflammation Associated with IgG4-Related Disease and Other Chronic Inflammatory Diseases: A Retrospective Observational Study.

INTRODUCTION: Immunoglobulin G4-related disease (IgG4-RD) is a systemic inflammatory disease characterized by elevated serum IgG4, tissue infiltration of IgG4-positive cells, and fibrosis. Although a number of IgG4-RD patients show sinonasal involvement, there is little known about sinonasal inflammation associated with IgG4-RD. This study aimed to describe the clinicopathological features of sinonasal inflammation associated with IgG4-RD and to compare with other inflammatory diseases, such as eosinophilic chronic rhinosinusitis (ECRS) and granulomatosis with polyangiitis (GPA). METHODS: A retrospective analysis of clinicopathological features of patients with sinonasal lesions and high serum IgG4 was performed. Patient data were reviewed to determine whether they fulfilled the diagnostic criteria for other inflammatory diseases. RESULTS: Six of 7 patients were diagnosed with IgG4-RD, while 1 patient was diagnosed with GPA. In the 6 patients with IgG4-RD, intranasal findings showed nasal polyps in 3 patients (50%) and nasal crusting in the 3 patients (50%). Computed tomography showed ethmoid sinus involvement in 5 patients (83%). Five of the 6 patients (83%) were diagnosed with IgG4-RD based on nasal biopsy, whereas 1 patient (17%) was diagnosed based on lacrimal gland biopsy. Four patients fulfilled the Japanese epidemiological survey of refractory ECRS (JESREC) criteria. However, none of the patients showed eosinophil infiltration. Although the patient with GPA showed high levels of serum IgG4 and tissue infiltration of IgG4-positive cells in the nasal biopsy, the patient showed common clinical features of GPA. CONCLUSION: Patients with sinonasal inflammation associated with IgG4-RD had similar clinical characteristics with ECRS and GPA. Histopathological findings of the nasal biopsy from clinically diagnosed GPA was consistent with that of IgG4-RD. Sinonasal inflammation associated with IgG4-RD should be diagnosed based not only on tissue infiltration of IgG4-positive cells but in conjunction with clinical findings such as local nasal characteristics, involvement of other organs, and serum antineutrophil cytoplasmic antibody levels. IgG4-RD should be ruled out in patients with eosinophilia without histopathological eosinophil infiltration.

Alterations of nasal microbiome in eosinophilic chronic rhinosinusitis.

BACKGROUND: Exposure to microbes may be important in the development of chronic rhinosinusitis (CRS). Dysbiosis of the nasal microbiome is considered to be related to CRS with nasal polyps (CRSwNP). The link between the nasal microbiota and eosinophilic CRSwNP (eCRSwNP) has rarely been studied. OBJECTIVE: The aim of this study was to rigorously characterize nasal dysbiosis in a cohort of patients with eCRSwNP and compare the nasal microbiomes of these patients with those of healthy controls (HCs). METHODS: We performed a cross-sectional study of 34 patients with eCRSwNP, 10 patients without CRSwNP, and 44 HCs by using 16S rRNA gene sequencing. An independent cohort of 14 patients with eCRSwNP, 9 patients without CRSwNP, and 11 HCs was used to validate the results. RESULTS: Compared with the nasal microbiome of healthy controls, the nasal microbiome of patients with eCRSwNP was characterized by higher α-diversity (Shannon and Chao1 index) and a distinct composition of microbes. Notably, the distinct differences in microbial composition between patients with eCRSwNP and HCs were significantly correlated with eCRSwNP disease status. Furthermore, in a diagnostic model generated by using these differences, a combination of 15 genera could be used to distinguish patients with eCRSwNP from HCs, with an area under the curve of approximately 0.8 in both the exploration and validation cohorts. CONCLUSION: Our study establishes the compositional alterations in the nasal microbiome in eCRSwNP and suggests the potential for using the nasal microbiota as a noninvasive predictive classifier for the diagnosis of eCRSwNP.

IL-21 induces pyroptosis of Treg cells via Akt-mTOR-NLRP3-caspase 1 axis in eosinophilic chronic rhinosinusitis.

BACKGROUND: Regulatory T (Treg) cells, which prevent inflammation-induced eosinophil infiltration, are deficient in nasal polyps (NPs) in patients with eosinophilic chronic rhinosinusitis (ECRS). It is concomitant with loss of Foxp3 after certain inflammatory stimuli. OBJECTIVE: We sought to determine the inflammatory cytokines involved in inducing the loss of Treg cells in NPs. METHODS: The abundance of cytokines in ECRS patients or mice were tested using ELISA, immunochemistry, immunofluorescence, quantitative reverse transcription PCR (qPCR), and/or flow cytometry. Expression of eosinophil cationic protein (ECP), CD4+ T cells, IL-4, and IL-17A and eosinophils in nasal mucosa of mouse model was investigated by immunochemistry, immunofluorescence, and hematoxylin and eosin staining. The percentage and death of induced Treg (iTreg) cells, source of IL-21 in NPs from ECRS and non-ECRS patients, and abundance of different systemic phenotypes of CD4+ T cells in a mouse model were studied by flow cytometry. Western blot analysis, scanning, and transmission electronic microscopy were used to detect pyroptosis of iTreg cells. RESULTS: IL-21 was highly expressed in nasal mucosa of ECRS patients and mice, causing pyroptosis and preventing development of iTreg cells in vitro. The elevated IL-21 in NPs from ECRS patients was mainly produced by CD3+ T cells, including T follicular helper, T peripheral helper, TH2, and TH17 cells and CD3+CD4- T cells. T peripheral helper cells and CD3+CD4- T cells were the predominant source of IL-21 in NPs from non-ECRS patients. Blocking IL-21/IL-21R signaling significantly reduced the number of eosinophils and CD4+ T cells along with ECP, IL-4, and IL-17A expression in the nasal mucosa of ECRS mice. It also increased Treg cell percentage and systemically decreased TH2 and TH17 ratios. Akt-mTOR inhibition prevented IL-21-induced pyroptosis in human and mouse iTreg cells. CONCLUSION: Elevated IL-21 drives pyroptosis and prevents Treg cell development in ECRS patients. IL-21 induced pyroptosis via activating Akt-mTOR-NLRP3-caspase 1 signaling.

An eosinophil peroxidase activity assay accurately predicts eosinophilic chronic rhinosinusitis.

BACKGROUND: A definitive diagnosis of eosinophilic chronic rhinosinusitis (eCRS) requires invasive surgical tissue sampling and histologic enumeration of intact eosinophils. Eosinophil peroxidase (EPX) is an accurate biomarker of sinonasal tissue eosinophilia in CRS regardless of polyp status. A less invasive and rapid method that accurately identifies tissue eosinophilia would be of great benefit to patients. OBJECTIVE: We sought to evaluate a new clinical tool that uses a nasal swab and colorimetric EPX activity assay to predict a diagnosis of eCRS. METHODS: A prospective, observational cohort study was conducted using nasal swabs and sinonasal tissue biopsies obtained from patients with CRS electing endoscopic sinus surgery. Patients were classified as non-eCRS (n = 19) and eCRS (n = 35) on the basis of pathologically determined eosinophil counts of less than 10 or greater than or equal to 10 eosinophils/HPF, respectively. Swab-deposited EPX activity was measured and compared with tissue eosinophil counts, EPX levels, and CRS-specific disease metrics. RESULTS: EPX activity was significantly increased in patients with eCRS than in patients without eCRS (P < .0001). With a relative absorbance unit cutoff value of greater than or equal to 0.80, the assay demonstrated high sensitivity (85.7%) and moderate specificity (79.0%) for confirming eCRS. Spearman correlations between EPX activity and tissue eosinophil counts (rs = 0.424), EPX levels (rs = 0.503), and Lund-Kennedy endoscopy scores (rs = 0.440) in eCRS were significant (P < .05). CONCLUSIONS: This investigation evaluates a nasal swab sampling method and EPX activity assay that accurately confirms eCRS. This method could potentially address the unmet need to identify sinonasal tissue eosinophilia at the point-of-care, as well as to longitudinally monitor eosinophil activity and treatment response.

Histone deacetylase activity is a novel target for epithelial barrier defects in patients with eosinophilic chronic rhinosinusitis with nasal polyps.

BACKGROUND: Studies have independently indicated that eosinophils and histone deacetylases (HDACs) may compromise the integrity of the epithelial barrier in nasal polyps; however, the underlying mechanisms are not clear. In this study, we aimed to investigate the role of eosinophilia and HDACs in regulation of tight junctions (TJs) and nasal epithelial barrier integrity in chronic rhinosinusitis with nasal polyps (CRSwNP) patients. METHODS: Expression of mRNAs and proteins of TJs and HDACs of biopsy specimens and air-liquid interface (ALI) human nasal epithelial cell cultures (HNECs) from eosinophilic and noneosinophilic CRSwNP patients and healthy controls was assessed. The ALI HNECs were also assessed for changes in transepithelial electrical resistance (TER) and paracellular flux of fluorescein isothiocyanate (FITC)-labelled dextran. Meanwhile, the assessments for the effect of HDAC inhibitor in eosinophilic nasal polyps were also conducted. RESULTS: Decreased TER and increased paracellular flux of FITC-labelled dextran in the ALI cultures were found in both eosinophilic and noneosinophilic CRSwNP, along with irregular, patchy and reduced expression of claudin-1, 4, 7, occludin, zonula occludens (ZO)-1 and ZO-2 and increased expression of HDAC1, 9 and SIRT7 for both ALI culture cells and biopsy specimens, especially for the eosinophilic CRSwNP group. Treatment of eosinophilic CRSwNP ALI-HNECs with an HDAC inhibitor improved the TJs expression and epithelial barrier integrity. CONCLUSIONS: Our data suggest that eosinophilia and HDACs influence epithelial barrier function in CRSwNP patients by regulating TJ protein expression. Targeting HDACs with specific inhibitors may be a potential treatment option for patients with eosinophilic CRSwNP.

Eosinophilic granulomatosis with polyangiitis developed after dupilumab administration in patients with eosinophilic chronic rhinosinusitis and asthma: a case report.

BACKGROUND: Eosinophilic granulomatosis with polyangiitis (EGPA) is a form of anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis characterized by eosinophil-rich granulomatous inflammation and small-to-medium vessel vasculitis associated with asthma, rhinosinusitis, and eosinophilia. EGPA is often difficult to distinguish from severe asthma and eosinophilic chronic rhinosinusitis (ECRS) in cases when there are no findings that suggest vasculitis. Dupilumab, an anti-IL-4Rα monoclonal antibody, is expected to be effective in eosinophilic airway inflammatory diseases, such as refractory asthma and chronic rhinosinusitis (CRS). Although transient eosinophilia and eosinophilic pneumoniae have been reported in patients with refractory asthma and CRS associated with dupilumab, few studies have examined the development of EGPA. CASE PRESENTATION: We report a case of a 61-year-old woman treated with dupilumab for refractory ECRS and eosinophilic otitis media (EOM) complicated by severe asthma. Although she had a previous history of eosinophilic pneumoniae and myeloperoxidase (MPO) ANCA positivity, there were no apparent findings of vasculitis before the initiation of dupilumab. After the second administration of dupilumab, several adverse events developed, including worsening of ECRS, EOM and asthma, and neuropathy. A blood test showed an eosoinophilia and re-elevation of MPO-ANCA levels after the administration of dupilumab. Therefore, dupilumab was discontinued owing to the development of EGPA, and prednisolone and azathioprine administration was initiated for a remission induction therapy. CONCLUSION: To the best of our knowledge, this is the first case report that suggests that dupilumab may directly trigger the manifestation of vasculitis in patients who were previously MPO-ANCA-positive. Although the precise mechanism of how dupilumab could trigger the development of EGPA requires further elucidation, measuring MPO-ANCA in patients with multiple eosinophilic disorders before the initiation of dupilumab might be helpful when considering the possibility of a latent EGPA. When administering dupilumab to patients with a previous history of MPO-ANCA positivity, clinicians must carefully monitor and collaborate with other specialists in the pertinent fields of study for appropriate usage.

Eosinophilic Chronic Rhinosinusitis and Pathogenic Role of Protease.

Chronic rhinosinusitis (CRS) is an inflammation of the nasal and paranasal sinus mucosa, and eosinophilic CRS (eCRS) is a subtype characterized by significant eosinophil infiltration and immune response by T-helper-2 cells. The pathogenesis of eCRS is heterogeneous and involves various environmental and host factors. Proteases from external sources, such as mites, fungi, and bacteria, have been implicated in inducing type 2 inflammatory reactions. The balance between these proteases and endogenous protease inhibitors (EPIs) is considered important, and their imbalance can potentially lead to type 2 inflammatory reactions, such as eCRS. In this review, we discuss various mechanisms by which exogenous proteases influence eCRS and highlight the emerging role of endogenous protease inhibitors in eCRS pathogenesis.

Therapeutic potential of recombinant human basic fibroblast growth factor on postoperative patients with chronic rhinosinusitis with nasal polyps.

OBJECTIVES: To explore the effect of intranasal administration of recombinant human basic fibroblast growth factor (rh-bFGF) on postoperative chronic rhinosinusitis with nasal polyps (CRSwNP) patients. DESIGN: A prospective, randomised, controlled, single-blinded trial. SETTING AND PARTICIPANTS: Seventy-five hospitalised patients who met the criteria of primary bilateral CRSwNP were enrolled from March 2020 to January 2021. MAIN OUTCOME MEASURES: Visual analogue scale, 22-item Sino-Nasal Outcome Test, Lund-Kennedy (L-K) system and scanning electron microscopy and quantitative real-time polymerase chain reaction. RESULTS: Seventy-five patients with CRSwNP were randomly assigned to three groups, and 72 patients completed the 1-month medication regimen and 1-year follow-up. Rh-bFGF nasal-spray and drop application reduced general nasal VAS scores within 2 weeks after endoscopic sinus surgery (ESS) compared to the control group. In contrast, only rh-bFGF nasal-drops reduced SNOT-22 scores at 2 weeks and 1 year compared with the control group. A significant reduction in the endoscopic L-K score was observed in the rh-bFGF nasal-spray and drop group compared with the control group. This is primarily because rh-bFGF promotes cilia growth in the nasal mucosal epithelium after the operation, as illustrated by scanning electron microscopy and expression of CP110, Tap73 and Foxj1 mRNA. For eosinophilic CRSwNP, the general VAS score of rh-bFGF nasal-drops was more obviously reduced compared to the control group after ESS. A similar trend was observed for L-K score. CONCLUSIONS: Rh-bFGF nasal-drops and sprays can quickly and effectively relieve postoperative symptoms and improve long-term prognosis of patients with CRSwNP. Moreover, rh-bFGF nasal-drops is also an effective method for postoperative patients with eosinophilic CRSwNP.

Dupilumab improves eosinophilic otitis media associated with eosinophilic chronic rhinosinusitis.

BACKGROUND: Eosinophilic otitis media (EOM) is a refractory condition associated with eosinophilic chronic rhinosinusitis and bronchial asthma. EOM is characterized by type-2 inflammation and is refractory to various treatments. We investigated the efficacy of dupilumab, interleukin-4 receptor alpha antagonist, for patients with EOM complicated by eosinophilic chronic rhinosinusitis (ECRS). METHODS: Between April 2017 and April 2022, we treated 124 patients with dupilumab for refractory CRS or bronchial asthma. Of these, 14 had EOM concurrently, and 10 of them who had been treated for >6 months were included in our study. We retrospectively evaluated the efficacy of dupilumab by the amount of systemic corticosteroid used, the frequency of exacerbations, severity score of EOM, computed tomography (CT) score of temporal bones, and pure tone audiometry. We also enrolled 8 EOM patients without dupilumab treatment as a control group. RESULTS: Dupilumab significantly improved the amount of systemic corticosteroid used and the frequency of exacerbation and compared with before dupilumab was used (p = 0.01 and <0.01, respectively). All patients could be weaned from systemic-corticosteroid therapy by 54 weeks of dupilumab use. The severity score of EOM and CT score for temporal bones were significantly lower than before the treatment (p = 0.01 and 0.01, respectively). Compared to the control group, the systemic corticosteroid used and severity scores were improved in the dupilumab group (p = 0.02 and < 0.01, respectively). CONCLUSIONS: Dupilumab could be used to wean patients from systemic corticosteroids with the improvement of severity score in EOM associated with ECRS and bronchial asthma.

[LOWER RESPIRATORY TRACT SCREENING USING FRACTIONAL EXHALED NITRIC OXIDE IN PATIENTS WITH EOSINOPHILIC CHRONIC RHINOSINUSITIS].

BACKGROUND: It is known that eosinophilic chronic rhinosinusitis is often associated with adult-onset bronchial asthma, and undiagnosed bronchial asthma is also known to be included. The purpose of this study is to screen patients with eosinophilic chronic rhinosinusitis using fractional exhaled nitric oxide, and to examine its usefulness in detecting undiagnosed bronchial asthma. METHODS: We retrospectively examined the data of patients with eosinophilic chrnoic rhinosinusitis who underwent surgical treatment at Kagawa University from April 2015 to July 2022. Patients were included if they received examinations of fractional exhaled nitric oxide and spirometry before surgical treatment. RESULTS: Of the 127 subjects, 52 had no history of treatment or diagnosis of bronchial asthma at the initial consultation. Among them, 15 patients who had high fractional exhaled nitric oxide value were diagnosed with bronchial asthma by the respiratory medicine department. Comorbid of bronchial asthma was eventually increased to 70.9% even though it was 59.1% at initial consultation. CONCLUSION: A certain number of patients with eosinophilic chronic rhinosinusitis have undiagnosed bronchial asthma, which can be difficult to detect with basic examination alone therefore fractional exhaled nitric oxide is useful as an additional screening examination.

Effect of Dupilumab on Depression in Asthma with Eosinophilic Chronic Rhinosinusitis in the Japanese Population.

INTRODUCTION: Psychological disorders, such as depression, are markedly prevalent in patients with airway diseases. In this study, we assessed the effect of treatment with dupilumab, an IL-4 receptor α chain antibody, on depressive symptoms in a cohort of patients with asthma with eosinophilic chronic rhinosinusitis (ECRS). METHODS: The study participants, diagnosed with asthma and ECRS, were assessed for symptoms and quality of life (QOL) scores for asthma and ECRS and medications. The Patient Health Questionnaire-9 (PHQ-9) scores were used to evaluate the depressive state. The depressive symptoms were compared with asthma and ECRS symptoms both at the time of initiation and after 4 months of dupilumab treatment. RESULTS: Ultimately, 31 patients were included in the study. Most patients demonstrated a depressive state that was correlated with the nasal symptom score. In the evaluation 4 months after dupilumab treatment, the PHQ-9 score was significantly reduced, and the decrease was remarkable in patients whose nasal symptom score was reduced by 50% or more. Additionally, the PHQ-9 scores in patients with improved nasal and asthma symptoms were significantly reduced. DISCUSSION/CONCLUSION: Dupilumab may improve QOL in patients with bronchial asthma with ECRS by reducing depressive symptoms through the improvement of clinical symptoms.

Efficacy of Endoscopic Posterior Nasal Neurectomy in Treating Eosinophilic Chronic Rhinosinusitis.

OBJECTIVES: Recent guidelines have revealed that eosinophilic chronic rhinosinusitis (ECRS) exhibits a strong tendency for recurrence after surgery and impairs quality of life. Neuropeptides play an important neuroimmunological role. The aim of this study was to determine the efficacy of posterior nasal neurectomy (PNN) for the treatment of ECRS by inhibiting type 2 cytokine expression. METHODS: Forty-six patients were divided into group A and group B according to a random number table. Group A underwent conventional functional endoscopic sinusitis surgery (FESS) combined with PNN, and group B underwent conventional FESS alone. The subjective and objective symptoms included a 10-cm visual analog scale (VAS), 22-item SinoNasal Outcome Test (SNOT-22) score, nasal speculum Lund-Kennedy score, and paranasal sinus computed tomography (CT) Lund-Mackay score at the 1-year postoperative follow-up. RESULTS: Postoperative VAS (10.33 ± 2.18 vs. 8.38 ± 2.11, p < 0.01) and Lund-Kennedy score (1.95 ± 1.32 vs. 3.14 ± 1.35, p < 0.01) were significantly improved. The rhinorrhea score (1.76 ± 0.83 vs. 2.90 ± 1.14, p < 0.001) in the VAS and the discharge (0.43 ± 0.51, vs. 0.95 ± 0.67, p < 0.01) and edema (0.57 ± 0.60 vs. 0.95 ± 0.59, p < 0.05) scores in the Lund-Kennedy score were observed to have improved significantly in group A compared with those in group B. CONCLUSIONS: FESS combined with PNN suppresses edema symptoms, which might significantly decrease the surgical recurrence rate of ECRS in the long term.

Eosinophils Correlate with Epithelial-Mesenchymal Transition in Chronic Rhinosinusitis with Nasal Polyps.

INTRODUCTION: Chronic inflammation and tissue remodeling always occur together in chronic rhinosinusitis (CRS). Epithelial-mesenchymal transition (EMT) plays a critical role in airway remodeling. OBJECTIVE: Changes of epithelial cells in sinus mucosa in different subtypes of CRS, especially in eosinophilic chronic rhinosinusitis with nasal polyps, and the role of EMT and eosinophils (EOS) in airway remodeling are still unknown. METHODS: We included 85 patients in this study. They were divided into 4 groups: a normal control (NC) group, a chronic rhinosinusitis without nasal polyps (CRSsNP) group, an eosinophilic chronic rhinosinusitis with nasal polyps (ECRSwNP) group, and a noneosinophilic chronic rhinosinusitis with nasal polyps (non-ECRSwNP) group. Clinical data were all collected and analyzed. Standard hematoxylin and eosin staining, immunohistochemical staining, and 2-color immunofluorescence staining were performed. Biomarkers of EMT, epithelial cadherin, and vimentin were labeled. The immunohistochemistry results of each group were counted and statistically analyzed. RESULTS AND CONCLUSION: E-cadherin was downregulated, and vimentin was upregulated in epithelial tissue from the ECRSwNP group, compared with that from the control group and the other groups. The number of vimentin-expressing epithelial cells correlated with sinus CT imaging Lund-Mackay scores (r = 0.560, p < 0.001). Moreover, expression levels of vimentin in the epithelium were associated with numbers of infiltrating EOS in tissues (r = 0.710, p < 0.001) and the peripheral blood EOS ratio (r = 0.594, p < 0.001). EMT occurred in patients with CRSwNP, especially in those with ECRSwNP. Epithelial reprogramming correlates with eosinophil infiltration and disease severity. Eosinophils contributed to impairment of epithelial function and promoted EMT in CRSwNP.

CCL4 Regulates Eosinophil Activation in Eosinophilic Airway Inflammation.

Eosinophilic chronic rhinosinusitis (ECRS) is a refractory airway disease accompanied by eosinophilic inflammation, the mechanisms of which are unknown. We recently found that CCL4/MIP-1ß-a specific ligand for CCR5 receptors-was implicated in eosinophil recruitment into the inflammatory site and was substantially released from activated eosinophils. Moreover, it was found in nasal polyps from patients with ECRS, primarily in epithelial cells. In the present study, the role of epithelial cell-derived CCL4 in eosinophil activation was investigated. First, CCL4 expression in nasal polyps from patients with ECRS as well as its role of CCL4 in eosinophilic airway inflammation were investigated in an in vivo model. Furthermore, the role of CCL4 in CD69 expression-a marker of activated eosinophils-as well as the signaling pathways involved in CCL4-mediated eosinophil activation were investigated. Notably, CCL4 expression, but not CCL5, CCL11, or CCL26, was found to be significantly increased in nasal polyps from patients with ECRS associated with eosinophil infiltration as well as in BEAS-2B cells co-incubated with eosinophils. In an OVA-induced allergic mouse model, CCL4 increased eosinophil accumulation in the nasal mucosa and the bronchoalveolar lavage (BALF). Moreover, we found that CD69 expression was upregulated in CCL4-stimulated eosinophils; similarly, phosphorylation of several kinases, including platelet-derived growth factor receptor (PDGFR)ß, SRC kinase family (Lck, Src, and Yes), and extracellular signal-regulated kinase (ERK), was upregulated. Further, CCR5, PDGFRß, and/or Src kinase inhibition partially restored CCL4-induced CD69 upregulation. Thus, CCL4, which is derived from airway epithelial cells, plays a role in the accumulation and activation of eosinophils at inflammatory sites. These findings may provide a novel therapeutic target for eosinophilic airway inflammation, such as ECRS.

[A CASE OF SEVERE ASTHMA RESULTING IN DISEASE EXACERBATION AFTER PROLONGATION OF THE DOSING INTERVAL AFTER LONG-TERM OMALIZUMAB ADMINISTRATION].

At the time of writing of this manuscript, four biologics were clinically available for the treatment of severe asthma, and there were no established recommendations for the period of administration or timing of discontinuation of each biologic. We present a case of severe asthma that was well controlled with long-term omalizumab treatment; however, prolongation of the dosing intervals resulted in disease exacerbation that was refractory to omalizumab treatment despite the restoration of the recommended interval of administration. We suspect that the prolonged dosing intervals might have reduced the efficacy of omalizumab. We report this case because dosing intervals should be considered in clinical practice in cases of long-term omalizumab treatment.

A murine model of eosinophilic chronic rhinosinusitis using the topical application of a vitamin D3 analog.

BACKGROUND: Eosinophilic chronic rhinosinusitis (ECRS) is a chronic inflammatory disease, characterized by eosinophilic infiltration, T-helper type 2 (Th2-type) response, and olfactory dysfunction. A master regulator of Th2-type inflammation, thymic stromal lymphopoietin (TSLP), is important for basophil activation. TSLP-elicited basophils are a key factor in the pathogenesis of ECRS. METHODS: In order to elucidate the mechanisms of ECRS in humans, we aimed to establish a murine model of ECRS based on TSLP production in response to the topical application of MC903 (a vitamin D3 analog) and the subsequent TSLP-induced basophil activation. Histological analyses were performed to assess immune cell infiltration into the nasal mucosa and to explore the impact of eosinophilic inflammation on the olfactory epithelium. The status of Th2-type inflammation was evaluated by quantitative real-time PCR and enzyme-linked immunosorbent assay (ELISA). RESULTS: Eosinophils, basophils, and M2 macrophages increased significantly in the nasal mucosa of the mice treated with MC903 and ovalbumin (OVA), compared to those treated with OVA alone or the controls. Quantitative real-time PCR and ELISA revealed elevated expression of interleukin (IL)-4, IL-5, IL-13, TSLP, the chemokine CCL11, and CCL24 in the nasal mucosa of the ECRS mice. In parallel, thinned olfactory epithelium and decreased mature olfactory sensory neurons were observed in the ECRS mice. CONCLUSIONS: Our model of ECRS displayed Th2-type inflammation in the sinonasal region, including both eosinophil infiltration and basophil infiltration. Additionally, olfactory epithelium turned out to be affected by eosinophilic inflammation. These features are consistent with the characteristics of the human ECRS.

Altered Immune Regulation of Dendritic Cells and Enhanced Cytokine Production of T Cells in the Pathogenesis of Eosinophilic Chronic Rhinosinusitis.

INTRODUCTION: Eosinophilic chronic rhinosinusitis (ECRS) is a refractory chronic disease defined by recurrent nasal polyps with severe eosinophilic infiltration. This is mainly due to enhanced type 2-dominant immune responses, but the underlying mechanism is still not fully understood. OBJECTIVE AND METHODS: In the present study, we aimed to determine the characteristics of dendritic cells (DCs) and cytokine profiles of T cells in the peripheral blood of individuals with ECRS and age- and sex-matched healthy controls (HC). RESULTS AND CONCLUSION: The ratios of myeloid (m)DC1s to DCs and PD-L1+ mDC1s to mDC1s were higher in ECRS patients than in HC. The proportions of plasmacytoid (p)DCs in DCs, and human leukocyte antigen-DR+ pDCs and ILT3+ pDCs in pDCs were lower in ECRS patients than in HC. In a characterization of T cells, IL-4+CD4+, IFN-γ+CD4+, IL-4+IFN-γ+CD4+, IL-4+Foxp3+CD4+, IFN-γ+Foxp3+CD4+, IFN-γ+IL-4-Foxp3-CD4+, IL-4+CD8+, IL-4+IFN-γ+CD8+, and IL-4+Foxp3+CD8+ T-cell populations were significantly higher in ECRS patients than in HC. These results suggest that the enhanced immune regulation of mDC1, diminished capacity of pDCs, and increased proportion of the T-cell phenotypes in peripheral blood might be factors in ECRS pathogenesis.

Distinct Patterns of Tissue Remodeling and Their Prognostic Role in Chronic Rhinosinusitis.

INTRODUCTION: Tissue remodeling refers to structural changes that occur in damaged tissue and is associated with disease severity in asthma. However, the characteristics of tissue remodeling and its prognostic role in chronic rhinosinusitis (CRS) remain unclear. In this report, we evaluated the clinical implications of tissue remodeling in CRS. METHODS: We performed a retrospective cohort study of adult patients who underwent endoscopic sinus surgery for bilateral CRS. The histopathology of sinus mucosa was determined by evaluating the inflammatory cell count and tissue remodeling markers (squamous metaplasia, subepithelial gland proliferation, basement membrane [BM] thickening, stromal edema, and fibrosis). Eosinophilic CRS (ECRS) was defined as an eosinophil count >15/high-power field in the biopsied tissue. Patient characteristics, allergy test grade, preoperative Lund-Mackay score (LMS), and pre- and postoperative Lund-Kennedy scores (LKSs) were analyzed. RESULTS: Of the identified patients, 59.1% were classified as ECRS and the remaining 40.9% as non-ECRS. Regarding tissue remodeling markers, stromal edema was seen in 90.9%, BM thickening in 63.6%, and stromal fibrosis in 34.1% of patients. In cases with stromal edema and BM thickening, greater tissue eosinophilia was observed, while stromal fibrosis decreased tissue eosinophilia (p < 0.05). Prognostically, subepithelial gland proliferation alone was an independent risk factor for poor postoperative endoscopic findings (odds ratio: 8.250, 95% confidence interval: 1.128-60.319, p = 0.038). CONCLUSIONS: Tissue eosinophilia was commonly associated with BM thickening and stromal edema. Subepithelial gland proliferation predicted a poor surgical prognosis in CRS. These findings imply that tissue remodeling provides additional information not only on the CRS endotype but also on the postsurgical prognosis.