Eosinophilic chronic rhinosinusitis

Tezepelumab treatment in severe asthma with recurrent chronic rhinosinusitis with nasal polyps: Case series

Background

Tezepelumab is a human IgG2 mAb that inhibits thymic stromal lymphopoietin (TSLP) and is approved for treatment of severe asthma. Bronchial asthma, usually a type 2 inflammatory disease, often co-occurs with chronic rhinosinusitis with nasal polyps (CRSwNP). However, tezepelumab has unknown effects on severe asthma with CRSwNP. Patients with CRSwNP are frequently candidates for endoscopic sinus surgery (ESS). CRSwNP is a crucial factor influencing asthma symptoms. However, some patients experience recurrent CRSwNP.

Objective

Tezepelumab was approved for use with CRSwNP, and TSLP is involved in the pathogenesis of CRSwNP. This study presents the cases of 2 patients with severe asthma complicated with recurrent CRSwNP after ESS in whom tezepelumab rapidly improved asthma and sinusitis symptoms.

Methods

We evaluated tezepelumab treatment in patients with severe asthma with recurrent CRSwNP based on symptoms, asthma exacerbation, level of type 2 cytokines, and lung function.

Results

After they had received a high-dose inhaled corticosteroid and long-acting β2-agonist, the patients' asthma remained uncontrolled, as defined by a low Asthma Control Test score. However, tezepelumab reduced severe asthma exacerbation, improved lung function, and controlled asthma symptoms. It improved CRSwNP, asthma-related symptoms, and exercise tolerance, and it inhibited type 2 cytokines extensively, indicating its effectiveness in treating CRSwNP. Tezepelumab was efficacious in these patients and improved their symptoms in terms of comorbidities of the upper and lower airways.

Conclusion

Tezepelumab was effective in treating asthma complicated with CRSwNP recurrence after ESS. However, further studies are required to identify the general and specific roles of tezepelumab in treating severe asthma and recurrent CRSwNP.

Luteolin alleviates olfactory dysfunction in eosinophilic chronic rhinosinusitis through modulation of the TLR4/NF-κB signaling pathway

OBJECTIVES

Eosinophilic chronic rhinosinusitis (ECRS) is characterized by early, severe olfactory dysfunction and a high recurrence rate, with inadequate treatments. This article aims to elucidate the potential mechanisms by which luteolin may treat olfactory dysfunction in the context of ECRS.

METHODS

Thirty C57 BL/6 mice were randomly assigned to five groups: a control group and four experimental groups (ECRS, ECRS + Luteolin (Low, Medium, High Dose)). We conducted RNA sequencing, behavioral testing, ELISA, PCR, HE staining, Western blot analysis, and immunofluorescence staining. Additionally, human olfactory epithelial Cells (HOEPCs) were treated with Luteolin, TAK-242, QNZ, and Luteolin + LPS to investigate the underlying mechanisms.

RESULTS

Luteolin significantly reduced IL-4, IL-5, and IL-13 levels in the nasal lavage fluid (NLF) of ECRS mice, improving olfactory function and restoring OMP+ mature and Gap43+ immature olfactory sensory neurons (OSNs). RNA sequencing revealed the involvement of the TLR4/NF-κB pathway in ECRS-related olfactory dysfunction and luteolin's therapeutic effects. Luteolin reduced TLR4+ cells, P65 nuclear translocation, and decreased protein levels of IL-1β, TLR4, MyD88, p-P65, P65, and p-P38. The treatment also lowered OSNs cell apoptosis by decreasing the levels of cleaved caspase-3 and caspase-9 levels, and increasing Bcl-2 protein. Antioxidant enzymes SOD, CAT, and GSH-Px were elevated, while MDA levels decreased. In ECRS HOEPCs, luteolin's anti-apoptotic effects on OSNs were reversed by LPS-induced TLR4/NF-κB activation.

CONCLUSIONS

Luteolin ameliorates olfactory dysfunction associated with ECRS by modulating the TLR4/NF-κB signaling pathway. This modulation results in a reduction of TH2-type inflammation, oxidative stress, and apoptosis in OSNs.

Supramolecular gel with enhanced immunomodulatory effects presents a minimally invasive treatment strategy for eosinophilic chronic rhinosinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) is an inflammatory disease characterized by persistent immune dysregulation, which presents considerable limitations in current medical therapy.

OBJECTS

This study investigates a supramolecular gel (PSPD), which aims to minimize systemic adverse effects through local injection, provide long-lasting anti-inflammatory effects, and modulate the mucosal immune microenvironment.

METHODS

The properties of PSPD were evaluated using rheological experiments. Biocompatibility assessments were conducted through CCK-8 and serum biochemical analyses. The balance between TH17 and Treg was determined using immunofluorescence (IF) and flow cytometry (FC). Additionally, sinus computed tomography (CT), and endoscopy were employed to evaluate mucosal swelling.

RESULTS

Rheological assessments revealed that PSPD possesses excellent self-healing and slow-release properties. CCK-8 and serum biochemical assays indicated that PSPD demonstrated superior biocompatibility. In nasal polyps, PSPD significantly inhibited IL17 expression. In an Eosinophilic Chronic Rhinosinusitis (ECRS) rat model, treatment with PSPD led to significant alleviation of nasal mucosal congestion. Furthermore, PSPD modulated the proliferation of TH17 and Treg as well as the expression of cytokines, ultimately reversing the TH17/Treg immune imbalance.

CONCLUSION

This multifunctional gel effectively sustains the modulation of TH17/Treg homeostasis, improving long-term disease management and representing a promising new therapeutic strategy for CRS, particularly in cases of ECRS.

The role of macrolides in chronic rhinosinusitis and nasal polyps

PURPOSE OF REVIEW

Chronic rhinosinusitis (CRS) is a heterogeneous condition, so personalized treatment based on each patient's pathophysiology is essential, rather than a one-size-fits-all approach. Drug therapy for CRS has evolved significantly in recent years with the introduction of biologics, necessitating a reconsideration of the role of low-dose and long-term administration of a 14-membered ring macrolide (macrolide therapy) in the treatment of CRS. Recent research on the mechanisms of macrolide therapy and its proper use may assist physicians in improving patients' quality of life and reducing disease burden.

RECENT FINDINGS

A classification of the pathogenesis of CRS based on endotype has been proposed, with type 2 inflammation playing a particularly important role as a refractory factor. Macrolide therapy improves CRS via immunomodulatory and anti-inflammatory effects rather than antimicrobial action, and it is expected to be effective in patients with neutrophil-dominant inflammation.

SUMMARY

Understanding the effectiveness and limitations of macrolide therapy is critical for making the best treatment decisions, especially when combined with surgery and other pharmacologic therapies. Therefore, selecting appropriate patients for macrolide therapy is critical for achieving adequate therapeutic efficacy.

Injectable Chitosan Hydrogel Particles as Nasal Packing Materials After Endoscopic Sinus Surgery for Treatment of Chronic Sinusitis

After endoscopic sinus surgery (ESS), nasal packing is often used to stop bleeding and promote wound healing. Because maintaining a moist environment is important to enhance wound healing, hydrogel-based wound dressings are effective to promote wound healing. Chitosan is used in the medical field because of its high hemostatic and wound healing properties. We developed a pH-neutral and non-toxic chitosan hydrogel, which was difficult to achieve using conventional methods. In this study, we show in animal experiments that the chitosan hydrogel (hydrogel particles) had higher wound healing properties than a commercially available solid wound dressing (dry state) composed of the same polymer. Additionally, we applied the injectable chitosan hydrogel particles as nasal packing materials to patients with bilateral chronic sinusitis undergoing ESS in a pilot clinical study. Concerning symptom scores, though the results narrowly missed statistical differences (p < 0.05), the average scores of our chitosan hydrogel were superior to those of a commercially available wound dressing (especially p = 0.09 for nasal bleeding). These findings suggest that the injectable chitosan hydrogel could be a viable option as a packing material following ESS.

Tissue Eosinophils Threshold and its Association with Adult-Onset Asthma in Chronic Rhinosinusitis

INTRODUCTION

Tissue eosinophil counts (TEC) might serve as a biomarker linking chronic rhinosinusitis (CRS) and the presence of adult-onset asthma. This study aimed to determine if TEC in sinus mucosa/polyps in CRS patients is an independent indicator of asthma and to identify its optimal cut-off point.

METHODS

This cross-sectional study was conducted on primary CRS patients scheduled for surgery. All patients were assessed by a pulmonologist for asthma diagnosis. Tissues were collected during surgery and evaluated for TEC. Logistic regression and receiver operating characteristic analysis were used to determine significant factors and the optimal cut-off points of TEC associated with asthma.

RESULTS

A total of 103 CRS patients were included. Ten patients (9.7%) had underlying asthma, while 13 (12.6%) were first diagnosed by the pulmonologist. TEC ≥40 cells per high-powered field (HPF) exhibited a significant correlation with asthma (area under the curve = 0.71, p < 0.001). The sensitivity of this cut-off point was 0.70 (95% confidence interval [CI] = 0.47-0.87), and specificity was 0.66 (95% CI = 0.55-0.76). Positive predictive value and negative predictive value were 0.37 and 0.88, respectively. The cut-off point significantly associated with the presence of asthma, with an adjusted odds ratio of 3.13 (95% CI = 1.05-9.35, p = 0.04), controlling for polyps, allergic rhinitis, and computerized tomography (CT) score.

CONCLUSION

TEC in CRS patients can help determine the presence of adult-onset asthma, with an optimal threshold of ≥40 cells/HPF. This threshold is significantly associated with asthma independent of polyps, allergy, and CT score.

Gαi1/3 signaling mediates IL-5-induced eosinophil activation and type 2 inflammation in eosinophilic chronic rhinosinusitis

Background

Uncontrolled severe eosinophilic chronic rhinosinusitis (eCRS) is associated with elevated levels of Th2 cells and raised immunoglobulin concentrations in nasal polyp tissue. eCRS is characterized by high eosinophilic infiltration and type 2 inflammation. Gαi1/3 proteins participate in allergic inflammation by regulating immune cells. Whether Gαi1/3 proteins have a role in the development of eCRS remains unknown.

Objectives

To investigate the association between Gαi1/3 expression levels and CRS and the underlying mechanisms.

Methods

Western blotting and immunohistology were used to detect Gαi1/3 expression. Correlations between Gαi1/3 and immune cells and clinical parameters were analyzed. Signaling pathway activation in IL-5-induced Gαi1/3-knockout or knockdown mouse embryonic fibroblasts (MEFs) and eosinophils (EoL-1 cells) was detected by western blotting. EdU/DAPI was used to evaluate the proliferation of EoL-1 cells. A CRS model was established using Gαi1/3-knockout mice, and histological analysis and inflammatory cytokine measurements were performed.

Results

Compared with the non-eCRS subset, the eCRS subset showed significantly increased Gαi1/3 expression levels. High nasal tissue Gαi1/3 levels were linked to high tissue eosinophil infiltration, and high disease severity and allergic conditions in CRS patients. Gαi1/3 were required for IL-5-induced Akt-mTOR and Erk activation in MEFs. In EoL-1 cells, Gαi1/3 was associated with IL-5-activated IL-5Rα, promoting IL-5Rα endocytosis and transducing downstream signaling. IL-5-induced EoL-1 cell proliferation and degranulation were suppressed after Gαi1/3 silencing. In a CRS murine model, immune cell infiltration and type 2 inflammation were largely impaired in Gαi1/3-double-knockout mice.

Conclusion

Increased Gαi1/3 expression levels in nasal tissue are linked to eosinophil infiltration and increased disease severity in CRS patients. Gαi1/3 contributes to eosinophil activation and participates in regulating allergic inflammation in CRS patients.

Biologics treatment for eosinophilic chronic rhinosinusitis complicated by bronchial asthma: Narrative review

There are 4 subtypes of chronic rhinosinusitis (CRS): eosinophilic CRS with nasal polyps (ECRSwNP), ECRS without NPs (ECRSsNP), non-ECRSwNP, and non-ECRSsNP. Most ECRS cases are categorized as ECRSwNP, and the number of patients with ECRSwNP has recently increased. ECRS is associated mainly with helper T-cell type 2 inflammation and eosinophils. Recently, Interleukin-25, -33, or TSLP, helper T-cell type 17, and Group 2 innate lymphoid cells have also been shown to be involved in the molecular mechanism of ECRS. ECRS can lead to several complications including bronchial asthma and/or aspirin intolerance. Conventionally, surgery and corticosteroids have been used to treat ECRS, but biologics have since been applied. Mepolizumab, benralizumab, and tezepelumab have been reported to improve asthma complicated by NPs more than asthma uncomplicated by NPs. Omalizumab, mepolizumab, benralizumab, and dupilumab have been reported to significantly improve Sinonasal Outcome Test-22 scores, nasal polyp scores, and nasal congestion severity in phase III trials. Benralizumab, dupilumab, and tezepelumab have been reported to improve both ECRS and complicated bronchial asthma.

Personalized Medicine in Chronic Rhinosinusitis: Treatable Traits Using Biologics for Unmet Needs

Chronic rhinosinusitis (CRS) is a prevalent airway disease, leading to health, social, and economic burdens, and substantially impairs quality of life. As CRS is heterogeneous and contains diverse pathogenesis, treatment outcomes and prognosis vary from curative to intractable. Inflammatory endotypes of CRS are divided into 3 types-type 1, type 2 and type 3-based on cytokines promoted. Tissue/blood eosinophilia seems to be the most reliable and feasible biomarker for type 2 CRS in clinical settings, although the cutoff level of eosinophilia remains to be elucidated. In East Asia, the predominant pathogenesis has changed from neutrophilic type 3 inflammation to eosinophilic type 2 inflammation over the past decades. The treatment strategy for CRS has also evolved from classical phenotype-based "reliever-controller" treatment to endotype-based "treatable traits" treatment. "Treatable traits" treatment is a personalized approach for the management of airway disease with complex and heterogeneous conditions. In CRS, traits can be grouped into sinonasal, extra-nasal and risk factor/behavioral domains. Type 2 CRS is one of the sinonasal traits, and biologics targeting immunoglobulin E, interleukin (IL)-5 and its receptor, IL-4/IL-13 receptor (IL-4/IL-13R) and thymic stromal lymphopoietin are the corresponding treatments for this trait. Proper use of these biologics can achieve high efficacy with patient satisfaction, leading to clinical remission. However, some cases show marked hypereosinophilia after the reduction or discontinuation of systemic corticosteroid or the switching of biologics from anti-IL-5/IL-5R to anti-IL-4Rα monoclonal antibody. More precise research on CRS targeting endotype, genotype, regiotype and theratype is needed to address the unmet needs and refine the "treatable traits" treatment of CRS.

CCL4 Affects Eosinophil Survival via the Shedding of the MUC1 N-Terminal Domain in Airway Inflammation

Eosinophilic chronic rhinosinusitis (ECRS), a CRS with nasal polyps (CRSwNP), is characterized by eosinophilic infiltration with type 2 inflammation and is highly associated with bronchial asthma. Intractable ECRS with poorly controlled asthma is recognized as a difficult-to-treat eosinophilic airway inflammation. Although eosinophils are activated and coincubation with airway epithelial cells prolongs their survival, the interaction mechanism between eosinophils and epithelial cells is unclear. This study examined the effect of eosinophils on mucin glycoprotein 1 (MUC1), a member of membrane-bound mucin, in the airway epithelial cells, to elucidate the mechanisms of the eosinophil-airway epithelial cell interaction. Nasal polyp samples from patients with CRSwNP and BEAS-2B airway epithelial cells, coincubated with purified eosinophils, were stained with two MUC1 antibodies. To confirm the involvement of CCL4, an anti-CCL4 neutralizing antibody or recombinant CCL4 was used as needed. The immunofluorescence results revealed a negative correlation between the expression of full-length MUC1 and eosinophil count in nasal polyps. In BEAS-2B coincubated with eosinophils, full-length MUC1, but not the C-terminal domain, was reduced, and eosinophil survival was prolonged, which was concomitant with CCL4 increase, whereas the anti-CCL4 neutralizing antibody decreased these reactions. The survival of eosinophils that contacted recombinant MUC1 without the N-terminal domain was prolonged, and recombinant CCL4 increased the expression of metalloproteases. Increased CCL4 induces the contact between eosinophils and airway epithelial cells by shedding the MUC1 N-terminal domain and enhances eosinophil survival in eosinophilic airway inflammation. This novel mechanism may be a therapeutic target for difficult-to-treat eosinophilic airway inflammation.

M2 macrophage derived HMOX1 defines chronic rhinosinusitis with nasal polyps

BACKGROUND

Molecular signatures of chronic rhinosinusitis with nasal polyps (CRSwNP) related to macrophages remain unclear. This study aimed to develop a macrophage-associated diagnostic signature for CRSwNP.

METHODS

Transcriptome data from 54 patients with CRSwNP and 37 healthy controls across GSE136825, GSE36830, and GSE72713 were used to identify differentially expressed genes (DEGs) between two groups. Gene Set Enrichment Analysis and Weighted Gene Co-Expression Network Analysis pinpointed crucial pathways and gene clusters. A diagnostic model was created from these analyses and receiver operating characteristic curve (ROC), and further validated in our transcriptome data from 29 samples. Immune cell infiltration analysis was performed and linked those diagnostic genes to macrophages and verified by single-cell RNA sequencing data. Immunofluorescence co-staining of CD163 and HMOX1 was performed in nasal tissues. Mouse bone marrow-derived macrophage (BMDMs) cultures were used in functional experiments. Correlations between the expression of HMOX1 and eotaxin genes were investigated.

RESULTS

DEGs of CRSwNP versus control group were enriched in the INTERLEUKIN_4_AND_13_SIGNALING pathways. A four-gene diagnostic model (HMOX1, ALOX5, F13A1 and ITGB2) was developed and demonstrated high diagnostic precision with an area under ROC curve of 0.980 for training dataset and 0.895 for test dataset. M2 macrophage presence and HMOX1 expression significantly correlated with CRSwNP (p < 0.001). Single-cell RNA sequencing data underscored the altered cellular composition in CRSwNP, with HMOX1 notably expressed in M2 macrophages. Immunofluorescence staining highlighted the increased infiltration of CD163+ M2 macrophages in nasal mucosa samples of eosinophilic CRSwNP, which correlated with HMOX1 protein levels (p < 0.05). The HMOX1 inhibitor zinc protoporphyrin reduced the ratio of CD163 + HMOX1 + M2 macrophages in mouse BMDM cultures (p < 0.05). HMOX1 expression showed a strong positive correlation with the expression of eotaxin genes (CCL11, CCL24, and CCL26; p < 0.05 respectively).

CONCLUSION

M2 macrophage-derived HMOX1 can be used as an innovative diagnostic signature for CRSwNP, which might be a potential regulator of eosinophilic inflammation.

High M2/M1 Macrophage Ratio Observed in Nasal Polyps Formed in Allergic Fungal Rhinosinusitis

Allergic fungal rhinosinusitis (AFRS) shares similarities with eosinophilic chronic rhinosinusitis (ECRS), both characterized by intractable nasal polyps. The key distinction lies in the presence of fungal infection within the nasal cavity. While ECRS nasal polyps are known for significant infiltration of M2 macrophages and eosinophils, as well as an increase in high endothelial venule (HEV)-like vessels, these features are less commonly reported in AFRS. This study compared clinicopathological findings between AFRS (n=10), ECRS (n=12), and non-ECRS (n=10) patients' nasal polyps using immunohistochemical analysis for CD163 and CD68 to assess the M2/M1 macrophage ratio, and peripheral lymph node addressin (PNAd) and CD34 to evaluate the proportion of HEV-like vessels. AFRS showed a significantly higher number of CD163-positive M2 macrophages and an increased M2/M1 ratio compared with ECRS. However, the percentage of HEV-like vessels and the number of eosinophils infiltrating the nasal polyps were similar in both AFRS and ECRS. The observed increase in M2 macrophages in AFRS nasal polyps is presumed to be induced by fungal infection in the nasal cavity, in comparison with ECRS. These results highlight the distinctive immunological profiles of AFRS and ECRS, emphasizing the role of macrophage polarization in their pathogenesis.

Diagnostic criteria for eosinophilic chronic rhinosinusitis: Comparative analysis and novel scoring system

BACKGROUND

Accurate identification of eosinophilic chronic rhinosinusitis is essentialg because its treatment and prognosis substantially differ from other subtypes.

METHODS

This retrospective observational study included 640 patients who underwent endoscopic sinus surgery for chronic rhinosinusitis in a single tertiary center from January 2021 to December 2022. Receiver operating characteristic curves were generated to compare accuracy, sensitivity, specificity of the novel scoring system, and previous diagnostic criteria (Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis, European Forum for Research and Education in Allergy and Airway Diseases, European Position Paper on Rhinosinusitis and Nasal Polyps, and Sakuma et al.) for predicting eosinophilic chronic rhinosinusitis (ECRS) by tissue eosinophil count ≥70 per high power field.

RESULTS

Patients were randomly divided into estimation (n = 430) and validation (n = 210) groups. The area under the receiver operating characteristic curve for the novel score was 0.753 (95% confidence interval [CI], 0.670-0.835) in the estimation group, 0.729 (0.629-0.830) in the validation group, and 0.661 (0.584-0.738) in the 20-fold cross-validation with the entire dataset.

CONCLUSIONS

We propose a novel scoring system that incorporates three key parameters: "novel score = blood eosinophil (%) + total Lund-Mackay score of anterior ethmoid sinuses + 2 if nasal polyp present" greater than 7 can be reliably used for diagnosing ECRS. This system can facilitate decision-making processes regarding the administration of oral steroids and biologics targeting type 2 inflammation prior to surgical intervention.

Significance as a Prognostic Factor of Eosinophil Count in Nasal Polyp Tissue in Patients with Chronic Rhinosinusitis Accompanied by Asthma

Background/Objectives: Patients with chronic rhinosinusitis (CRS) accompanied by asthma often show poor prognoses and require continuous management. This study aimed to assess the prognostic value of eosinophil counts in nasal polyp tissue for selecting individuals who would benefit from ongoing management in CRS patients with asthma. Methods: Patients with asthma who underwent endoscopic sinus surgery for CRS with nasal polyps were included in the study. Eosinophil counts in nasal polyp tissues were quantified, and retrospective data were collected from laboratory and clinical findings, including endoscopic examinations, CT scans, and Japan Endoscopic Sinus Surgery Rating and Evaluation Committee (JESREC) scores. Disease control status was evaluated through endoscopic examination 6 months post-surgery. Results: A total of 42 patients were divided into two groups based on their disease management status 6 months post-operation: the well-control group (24 patients, 57.14%) and the poor-control group (18 patients, 42.86%). Demographics and laboratory findings did not show significant differences between the groups. However, the JESREC score (p = 0.04) and tissue eosinophil count (p = 0.02) were significantly different. Multivariate analysis identified tissue eosinophil count as the only risk factor associated with prognosis, with a cut-off value of 90/HPF. Conclusions: In CRS patients with asthma, high tissue eosinophil counts in nasal polyps were associated with poor disease control, which is the most potent predictor of prognosis. The assessment of eosinophil counts in nasal polyp tissue could aid in identifying patients who would benefit from continuous management and tailored interventions for improved outcomes.

The NLRP3 inflammasome in allergic diseases: mechanisms and therapeutic implications

In recent years, there has been a global increase in the prevalence of allergic diseases, including allergic rhinitis, chronic rhinosinusitis, allergic asthma, atopic dermatitis, allergic conjunctivitis, and food allergies. Since the pathogenic mechanisms of these allergic diseases are not yet fully understood, targeted and effective therapies are lacking. The NLRP3 inflammasome, a multiprotein complex implicated in various inflammatory diseases, can be activated by diverse stimuli. It assembles into NLRP3 inflammasome complexes through conformational changes, initiating the proteolytic cleavage of dormant procaspase-1 into active caspase-1 and promoting the maturation of inflammatory cytokines, including IL-1β and IL-18. Dysfunction of the NLRP3 inflammasome may serve as a key driver of inflammatory diseases, leading to pyroptosis and amplifying the local inflammatory response. As preliminarily demonstrated, specific NLRP3 inflammatory vesicle inhibitors play refectory roles in animal models of allergic diseases, and it is believed that specific NLRP3 inflammasome inhibitors may be potential therapeutic agents for allergic diseases. This review highlights the progress of research on the NLRP3 inflammasome in allergic diseases, explores its contribution to different types of allergic diseases, and identifies promising clinical targets for intervention.

Safety and effectiveness of a drug-loaded haemostatic sponge in chronic rhinosinusitis: a randomized, controlled, double-blind study

Some cases of chronic rhinosinusitis (CRS) require surgical treatment and postoperative nasal packing, but bleeding and adhesion are common complications after nasal surgery. Biodegradable drug-loaded implants hold great therapeutic options for the treatment of CRS, but little data are available regarding the safety and efficacy of a novel drug-loaded haemostatic sponge (DLHS) in the sinus. The aim of this study was to investigate the safety and efficacy of DLHS in the sinus. We conducted a prospective, randomized, controlled, double-blind clinical trial. In this clinical trial, 49 patients were enrolled and randomly divided into 2 groups: group A (n = 25) had the DLHS containing 1 mg budesonide and 0.67 mg sodium hyaluronate placed into the sinus, and group B (n = 24) had the Nasopore placed after ESS. Endoscopic follow-up was performed for 12 weeks, and the findings were classified using the discharge, inflammation, polyps/oedema (DIP) endoscopic appearance scores. All patients completed questionnaires to evaluate their sinonasal symptoms by using the sinonasal outcome test-22 (SNOT-22) Chinese version and visual analogue scale (VAS). Serum cortisol concentration in group A was measured prior to surgery and at days 1, 3, 7, and 14 after nasal surgery. Comparing group A and group B, at 2 weeks, no significant differences were observed in either objective or subjective parameters. The mean value of VAS for rhinorrhoea and DIP for oedema and the mean value of nasal adhesion were significantly lower in Group A than in Group B at 6 and 12 weeks, but a significant difference did not occur in SNOT-22 and VAS for dysosmia between the two groups at 6 and 12 weeks. The mean serum cortisol concentrations in group A at the follow-up were within normal limits without remarkable fluctuations. This study demonstrates the safety and efficacy of a novel biodegradable DLHS with the possibility of being used in CRS patients, and this sponge may reduce inflammation and minimize adhesions via controlled local drug delivery without measurable systemic exposure.

Eosinophils as drivers of bacterial immunomodulation and persistence

Traditionally, eosinophils have been linked to parasitic infections and pathological disease states. However, emerging literature has unveiled a more nuanced and intricate role for these cells, demonstrating their key functions in maintaining mucosal homeostasis. Eosinophils exhibit diverse phenotypes and exert multifaceted effects during infections, ranging from promoting pathogen persistence to triggering allergic reactions. Our investigations primarily focus on Bordetella spp., with particular emphasis on Bordetella bronchiseptica, a natural murine pathogen that induces diseases in mice akin to pertussis in humans. Recent findings from our published work have unveiled a striking interaction between B. bronchiseptica and eosinophils, facilitated by the btrS-mediated mechanism. This interaction serves to enhance pathogen persistence while concurrently delaying adaptive immune responses. Notably, this role of eosinophils is only noted in the absence of a functional btrS signaling pathway, indicating that wild-type B. bronchiseptica, and possibly other Bordetella spp., possess such adeptness in manipulating eosinophils that the true function of these cells remains obscured during infection. In this review, we present the mounting evidence pointing toward eosinophils as targets of bacterial exploitation, facilitating pathogen persistence and fostering chronic infections in diverse mucosal sites, including the lungs, gut, and skin. We underscore the pivotal role of the master regulator of Bordetella pathogenesis, the sigma factor BtrS, in orchestrating eosinophil-dependent immunomodulation within the context of pulmonary infection. These putative convergent strategies of targeting eosinophils offer promising avenues for the development of novel therapeutics targeting respiratory and other mucosal pathogens.

Is the measurement of ethmoid sinus dominance in eosinophilic chronic rhinosinusitis accurate?

OBJECTIVE

An ethmoid-dominant shadow on computed tomography is an indicator of type 2 inflammation, and is one of the main items used to diagnose and classify the severity of eosinophilic chronic rhinosinusitis in the Japanese diagnostic criteria. Ethmoid sinus dominance is examined using the Lund-Mackay scoring system and may be overestimated due to scoring characteristics. We aim to investigate the accuracy of evaluations of ethmoid dominance using the conventional scoring system and the possibility of conducting an objective evaluation using a more detailed other scoring system.

METHODS

Patients diagnosed with eosinophilic chronic rhinosinusitis and who underwent bilateral endoscopic sinus surgery were enrolled in the present study. Computed tomography was performed preoperatively on all subjects. The bilateral anterior and posterior ethmoid sinuses and bilateral maxillary sinus were scored, and the ethmoid-to-maxillary ratio was calculated using 3 different scoring systems: Lund-Mackay (each sinus score ranges between 0 and 2), simplified Zinreich (score ranging between 0 and 3), and Zinreich (score ranging between 0 and 5).

RESULTS

A total of 149 patients were eligible for the present study. Significant differences were observed in ethmoid-to-maxillary ratio evaluated by the 3 different scoring systems (2.4 ± 0.7, 3.0 ± 1.1, and 3.7 ± 2.2). Only 2 patients were negative for ethmoid dominance by the Lund-Mackay scoring system, while 14 were negative by the simplified-Zinreich and Zinreich scoring systems. Severity changed from the initial grade in 12 patients.

CONCLUSIONS

The present results confirmed a potential overestimation when only the Lund-Mackay scoring system was used to assess ethmoid dominance. Ethmoid dominance has been identified as one of the main predictive factors for the long-term postoperative outcomes of eosinophilic chronic rhinosinusitis and is included in the Japanese diagnostic criteria. A detailed evaluation of ethmoid dominance is desirable for more accurate evaluations of the severity and prognosis of eosinophilic chronic rhinosinusitis.

LEVEL OF EVIDENCE: 4

A Case of Sinonasal Inverted Papilloma Suspected as Postoperative Recurrence of Eosinophilic Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) is a persistent inflammatory disease affecting the nasal and paranasal sinus tissues, classified into two main categories: one associated with nasal polyps (CRSwNP) and one without them (CRSsNP). A particular form of CRSwNP, known as eosinophilic CRS (ECRS), is distinguished by the excessive presence of eosinophils in the affected tissues. While surgical intervention and corticosteroids are the standard treatments, high relapse rates have led to increasing interest in biological treatments. Inverted papilloma (IP), a benign yet recurrent tumor with potential for malignancy, often complicates diagnosis when concurrent inflammation is present. We present a case of a 56-year-old man with a long-standing history of ECRS, initially suspected to have experienced a recurrence. Imaging suggested the possibility of IP, but biopsy results showed a marked increase in eosinophil levels. Following surgery, the diagnosis of IP was confirmed, and no malignancy was found. A year after surgery, the patient remained free of recurrence. This case emphasizes the difficulty of differentiating ECRS from IP due to their overlapping histological features. To ensure accurate diagnosis, a thorough evaluation combining radiological, endoscopic, and pathological methods is crucial.

The Role of the Gut and Airway Microbiota in Chronic Rhinosinusitis with Nasal Polyps: A Systematic Review

In recent years, there has been growing interest in understanding the potential role of microbiota dysbiosis or alterations in the composition and function of human microbiota in the development of chronic rhinosinusitis with nasal polyposis (CRSwNP). This systematic review evaluated the literature on CRSwNP and host microbiota for the last ten years, including mainly nasal bacteria, viruses, and fungi, following the PRISMA guidelines and using the major scientific publication databases. Seventy original papers, mainly from Asia and Europe, met the inclusion criteria, providing a comprehensive overview of the microbiota composition in CRSwNP patients and its implications for inflammatory processes in nasal polyps. This review also explores the potential impact of microbiota-modulating therapies for the CRSwNP treatment. Despite variability in study populations and methodologies, findings suggest that fluctuations in specific taxa abundance and reduced bacterial diversity can be accepted as critical factors influencing the onset or severity of CRSwNP. These microbiota alterations appear to be implicated in triggering cell-mediated immune responses, cytokine cascade changes, and defects in the epithelial barrier. Although further human studies are required, microbiota-modulating strategies could become integral to future combined CRSwNP treatments, complementing current therapies that mainly target inflammatory mediators and potentially improving patient outcomes.

Eosinophilic mucus diseases

Eosinophilic inflammation is primarily characterized by type 2 immune responses against parasitic organisms. In the contemporary human being especially in developed countries, eosinophilic inflammation is strongly associated with allergic/sterile inflammation, and constitutes an undesired immune reaction. This situation is in stark contrast to neutrophilic inflammation, which is indispensable for the host defense against bacterial infections. Among eosinophilic inflammatory disorders, massive accumulation of eosinophils within mucus is observed in certain cases, and is often linked to the distinctive clinical finding of mucus with high viscosity. Eosinophilic mucus is found in a variety of diseases, including chronic allergic keratoconjunctivitis, chronic rhinosinusitis encompassing allergic fungal sinusitis, eosinophilic otitis media, eosinophilic sialodochitis, allergic bronchopulmonary aspergillosis/mycosis, eosinophilic plastic bronchitis, and eosinophilic asthma. In these pathological conditions, chronic inflammation and tissue remodeling coupled with irreversible organ damage due to persistent adhesion of toxic substances and luminal obstruction may impose a significant burden on the body. Eosinophils aggregate in the hyperconcentrated mucus together with cell-derived crystals, macromolecules, and polymers, thereby affecting the biophysical properties of the mucus. This review focuses on the clinically significant challenges of mucus and discusses the consequences of activated eosinophils on the mucosal surface that impact mucus and persistent inflammation.

Necroptosis in bacterial infections

Necroptosis, a recently discovered form of cell-programmed death that is distinct from apoptosis, has been confirmed to play a significant role in the pathogenesis of bacterial infections in various animal models. Necroptosis is advantageous to the host, but in some cases, it can be detrimental. To understand the impact of necroptosis on the pathogenesis of bacterial infections, we described the roles and molecular mechanisms of necroptosis caused by different bacterial infections in this review.

Association Between Serum Amyloid A Expression and Disease Control after Endoscopic Sinus Surgery in Patients With Chronic Rhinosinusitis With Nasal Polyps

OBJECTIVE

Our previous study revealed that serum amyloid A (SAA) levels in polyp tissues could serve as a biomarker for the prediction of corticosteroid insensitivity in patients with chronic rhinosinusitis with nasal polyps (CRSwNP). However, their association with disease control status in the patients after endoscopic sinus surgery remains to be assessed.

METHODS

Polyp tissues and control uncinate process mucosa were collected from 48 patients with CRSwNP and 10 healthy control subjects. SAA expression was examined using immunohistochemistry and enzyme-linked immunosorbent assay. Receiver operating characteristic (ROC) curves were performed to determine the predictive value of SAA in nasal polyps. The clinical characteristics of 2 CRSwNP subtypes (SAAhigh and SAAlow) were evaluated.

RESULTS

The SAA expression levels in polyp tissues were significantly elevated both in non-eosinophilic and eosinophilic CRSwNP as compared to the healthy controls. In patients with CRSwNP, the tissue SAA level was significantly higher in the disease-controlled patients than those of the partly controlled and uncontrolled. ROC curve analysis revealed that a cut-off value of 114.9 ng/mL for the tissue SAA level predicted the patients with disease-controlled status with 93.33% sensitivity and 63.64% specificity (AUC = .8727, P < .001). Furthermore, The SAAhigh subgroup showed higher tissue eosinophil numbers and percentage of the disease-controlled patients compared to the SAAlow subgroup.

CONCLUSIONS

Our findings suggest that measurements of SAA in polyp tissues may provide useful information for evaluating CRSwNP conditions, especially identifying the CRSwNP patients with disease-controlled status after endoscopic sinus surgery.

Comparison of cytokine expression and disease severity between plasma cell-dominant and eosinophil-dominant patients in chronic rhinosinusitis with nasal polyps

PURPOSE

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a heterogeneous disease characterized by inflammation of the nasal and sinus mucosa. The inflammatory patterns may differ among patients, leading to different subtypes based on the dominant inflammatory cell type. This study aimed to compare the differences in cytokine expression and disease severity between plasma cell-dominant and eosinophil-dominant subtypes in patients with CRSwNP.

METHODS

This study included 53 CRSwNP patients and 19 control subjects who did not have asthma or a history of cigarette smoking. The expression of cytokines and inflammatory cells was assessed via enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry, respectively.

RESULTS

Among the cytokines analyzed, only IL-6 was significantly different between the two subtypes. A greater proportion of mast cells and IgE cells was present in plasma cell-dominant CRSwNP patients than in eosinophil-dominant group. For the three disease severity scores (LMK-CT, TPS and SNOT-22), objective scores (LMK-CT and TPS) were greater in the eosinophil-dominant CRSwNP group, while the opposite result was shown for the subjective score (SNOT-22). Additionally, the percentage of plasma cell-dominant cells was significantly positively correlated with disease severity according to the TPS and SNOT-22 scores.

CONCLUSIONS

Our data revealed that plasma cell-dominant inflammation, a subtype of type 2 CRS, was significantly correlated with subjective disease severity. The study also highlights the role of IL-6, IgE and mast cells as distinguishing factors between eosinophil-dominant and plasma cell-dominant CRSwNP. This information could be useful for clinical diagnosis and personalized treatment.

Multi-Disciplinary Expert Perspective on the Management of Type 2 Inflammation-Driven Severe CRSwNP: A Brief Overview of Pathophysiology and Recent Clinical Insights

Severe chronic rhinosinusitis with nasal polyposis (CRSwNP) is a disabling airway disease that significantly impacts patients' lives through the severity of symptoms, the need for long-term medical treatment and the high risk of recurrence post-surgery. Biological agents targeting type 2 immune responses underlying the pathogenesis of CRSwNP have shown effectiveness in reducing polyp size and eosinophilic infiltrate, and in decreasing the need for additional sinus surgeries. However, despite recent progress in understanding and treating the disease, type 2 inflammation-driven severe CRSwNP continues to pose challenges to clinical management due to several factors such as persistent inflammation, polyp recurrence, heterogeneity of disease, and comorbidities. This article presents the findings of a scientific discussion involving a panel of ear, nose and throat (ENT) specialists and pulmonologists across Sweden and Finland. The discussion aimed to explore current management practices for type 2 inflammation-driven severe CRSwNP in the Nordic region. The main topics examined encompassed screening and referral, measurements of disease control, treatment goals, and future perspectives. The experts emphasized the importance of a collaborative approach in the management of this challenging patient population. The discussion also revealed a need to broaden treatment options for patients with type 2 inflammation-driven CRSwNP and comorbid conditions with shared type 2 pathophysiology. In light of the supporting evidence, a shift in the disease model from the presence of polyps to that of type 2 inflammation may be warranted. Overall, this discussion provides valuable insights for the scientific community and can potentially guide the future management of CRSwNP.

MicroRNA-145-5p Regulates the Epithelial-Mesenchymal Transition in Nasal Polyps by Targeting Smad3

OBJECTIVES

The annual prevalence of chronic rhinosinusitis (CRS) is increasing, and the lack of effective treatments imposes a substantial burden on both patients and society. The formation of nasal polyps in patients with CRS is closely related to tissue remodeling, which is largely driven by the epithelial-mesenchymal transition (EMT). MicroRNA (miRNA) plays a pivotal role in the pathogenesis of numerous diseases through the miRNA-mRNA regulatory network; however, the specific mechanism of the miRNAs involved in the formation of nasal polyps remains unclear.

METHODS

The expression of EMT markers and Smad3 were detected using western blots, quantitative real-time polymerase chain reaction, and immunohistochemical and immunofluorescence staining. Differentially expressed genes in nasal polyps and normal tissues were screened through the Gene Expression Omnibus database. To predict the target genes of miR-145-5p, three different miRNA target prediction databases were used. The migratory ability of cells was evaluated using cell migration assay and wound healing assays.

RESULTS

miR-145-5p was associated with the EMT process and was significantly downregulated in nasal polyp tissues. In vitro experiments revealed that the downregulation of miR-145-5p promoted EMT. Conversely, increasing miR-145-5p levels reversed the EMT induced by transforming growth factor-β1. Bioinformatics analysis suggested that miR-145-5p targets Smad3. Subsequent experiments confirmed that miR-145-5p inhibits Smad3 expression.

CONCLUSION

Overall, miR-145-5p is a promising target to inhibit nasal polyp formation, and the findings of this study provide a theoretical basis for nanoparticle-mediated miR-145-5p delivery for the treatment of nasal polyps.

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.

Role of basal cells in nasal polyp epithelium in the pathophysiology of eosinophilic chronic rhinosinusitis (eCRS)

BACKGROUND

Basal cell hyperplasia is commonly observed in nasal polyp epithelium of eosinophilic chronic rhinosinusitis (eCRS). We examined the function and mechanisms of basal cell hyperplasia in the pathophysiology of eCRS.

METHODS

We found that normal human bronchial epithelial (NHBE) cells obtained basal cell characteristics when cultured with PneumaCult™-Ex Plus Medium. Most of the cells passaged three times expressed basal cell surface markers CD49f and CD271 by flow cytometry, and basal cell nuclear marker p63 by immunohistochemical staining. We named these NHBE cells with basal cell characteristics cultured Basal-like cells (cBC), and NHBE cells cultured with BEGM™ cultured Epithelial cells (cEC). The characteristics of cBC and cEC were examined and compared by RNA sequencing, RT-PCR, ELISA, and cell proliferation studies.

RESULTS

RNA sequencing revealed that cBC showed higher gene expression of thymic stromal lymphopoietin (TSLP), IL-8, TLR3, and TLR4, and lower expression of PAR-2 compared with cEC. The mRNA expression of TSLP, IL-8, TLR3, and TLR4 was significantly increased in cBC, and that of PAR-2 was significantly increased in cEC by RT-PCR. Poly(I:C)-induced TSLP production and LPS-induced IL-8 production were significantly increased in cBC. IL-4 and IL-13 stimulated the proliferation of cBC. Finally, the frequency of p63-positive basal cells was increased in nasal polyp epithelium of eCRS, and Ki67-positive proliferating cells were increased in p63-positive basal cells.

CONCLUSIONS

Type 2 cytokines IL-4 and IL-13 induce basal cell hyperplasia, and basal cells exacerbate type 2 inflammation by producing TSLP in nasal polyp of eCRS.

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.

Pathogenesis-based application of biologics for chronic rhinosinusitis: Current and future perspectives

Chronic rhinosinusitis (CRS) is heterogeneous and contains diverse pathogenesis including type 1, type 2, and/or type 3 inflammation. For severe type 2 CRS especially CRS with nasal polyps (CRSwNP), biologics that target inflammatory molecules have recently been applied along with further changes in the treatment algorithm for CRS. Currently, a completed phase 3 clinical trial for biologics for severe CRSwNP with inadequate response to surgery and/or intranasal corticosteroids, including omalizumab (anti-IgE), mepolizumab (anti-IL-5), benralizumab (anti-IL-5Rα), and dupilumab (anti-IL-4Rα), have all shown efficacy. Similar phase 3 clinical trials for tezepelumab (anti-TSLP) and etokimab (anti-IL-33) are now underway and completed, respectively. Further studies need to evaluate how to optimally and cost-effectively use biologics for CRS and determine if any biomarkers are indicative of which biologics should be administered. A definition of complete and/or clinical remission of CRS is also needed to determine when to reduce or discontinue biologics. In addition, more precise basic research on CRS, such as endotyping and genotyping, will need to be undertaken in order to determine novel targets for biologics.

Diagnostic significance of peripheral blood indices for eosinophilic chronic rhinosinusitis in Chinese adults

OBJECTIVE

Eosinophilic chronic rhinosinusitis (eCRS) is a refractory subtype of CRS. This study aimed to compare the differences in clinical features and peripheral blood indices between eCRS and non-eCRS Chinese patients and identify the predictive factors for eCRS.

METHODS

In this study, a total of 1352 patients with CRS were enrolled and divided into eCRS and non-eCRS groups based on the degree of eosinophilic infiltration in histopathology, and their demographic and clinical characteristics, as well as peripheral blood indices, were compared. Logistic regression analysis was used to identify the factors associated with eCRS, and the optimal cut-off values of predictors were determined using subject working curves.

RESULTS

As compared to those in the non-eCRS group patients, the proportion of males, age, proportion of smokers, peripheral blood eosinophil count, and erythrocyte count were significantly higher, while the peripheral blood neutrophil count, platelet count, neutrophil/lymphocyte count ratio (NLR), platelet/lymphocyte count ratio (PLR), and neutrophil × platelet/lymphocyte count ratio (SII index) were significantly lower in the eCRS group patients. Logistic regression analysis showed that age, peripheral blood neutrophil count, eosinophil count, and platelet count were independent predictors of eCRS, and eosinophil count > 2.05 × 108/L could be used as a diagnostic marker for eCRS with a sensitivity and specificity of 87.1% and 78.3%, respectively.

CONCLUSIONS

There were significant differences in the clinical features of eCRS and non-eCRS patients. Peripheral blood eosinophil count could early and more accurately predict eCRS.

Endotypic heterogeneity and pathogenesis in chronic rhinosinusitis

PURPOSE OF REVIEW

This review aims to provide updates in realms of endotypic heterogeneity, pathogenesis at the molecular level, potential of biomarkers, and cutting-edge scope of biologics in CRS.

RECENT FINDINGS

High-dimensional analyses, such as transcriptomes, and machine learning, have significantly enhanced CRS endotyping, uncovering diverse pathogenetic mechanisms contributing to its heterogeneity. The dynamic process of epithelial remodeling in CRS pathogenesis has gained more clarity and support as exemplified by IL-13 and oncostatin M (OSM) that are shown intricately linked to epithelial barrier dysfunction. Moreover, anti-dsDNA autoantibody, BAFF, periostin, and cystatin SN show promise as potentials biomarkers, offering diagnostic and prognostic value for CRS.

SUMMARY

The identification of inflammatory molecules involved in endotype specific signaling pathways provides insights into the underlying mechanisms and verifiable biomarkers for diagnosis and prediction of disease severity. More comprehensive clinical studies should be conducted to facilitate biologics from bench to bedside in treating CRS.

Usefulness of post-operative endoscopic score for optimal treatment selection in recurrent eosinophilic chronic rhinosinusitis

OBJECTIVE

This study retrospectively analysed post-operative endoscopic scores to determine the optimal post-operative treatment in patients with eosinophilic chronic rhinosinusitis undergoing functional endoscopic sinus surgery.

METHODS

In total, 339 adults who underwent initial bilateral functional endoscopic sinus surgery for eosinophilic chronic rhinosinusitis were enrolled. Patients were divided into group A, which required no additional post-operative treatment; group B, which required local/systemic steroids post-operatively; and group C, which further required dupilumab and/or revision surgery.

RESULTS

Sixty-five per cent of patients could be treated with initial functional endoscopic sinus surgery (group A). Post-operative steroids were required in 35 per cent of patients with a post-operative endoscopic score of 30 per cent (group B). Further advanced treatments with dupilumab and/or revision functional endoscopic sinus surgery were required in 10 per cent of patients with a post-operative endoscopic score of 65 per cent (group C).

CONCLUSION

The post functional endoscopic sinus surgery endoscopic score can be used as an index to determine treatment at the time of eosinophilic chronic rhinosinusitis recurrence.

Assessment of eosinophilic rhinosinusitis cases that required secondary treatment (biologics or reoperation) during long-term postoperative courses

OBJECTIVE

Endoscopic sinus surgery (ESS) is selected as the primary treatment for eosinophilic chronic rhinosinusitis (ECRS). Biologics or reoperation are sometimes required as secondary treatment after ESS. The present study examined the long-term postoperative courses of ECRS cases treated according to the current treatment concept, the frequency of secondary treatment, and its predictive factors.

METHODS

Ninety-four patients with ECRS who underwent ESS and received continuous management for 1-5 years were retrospectively investigated. Patient characteristics, long-term changes in endoscopic scores and the results of olfactory function tests, and secondary treatment were evaluated.

RESULTS

Five patients underwent reoperation and 11 received dupilumab during the follow-up period (35.9±19.2 months). Sixteen patients (17%) required secondary treatment due to the deterioration of sinus conditions. These patients were significantly younger, had higher comorbidity rates of allergic rhinitis and bronchial asthma, and a higher preoperative CT score than those who did not require secondary treatment. Three months after surgery, CT scores, endoscopic scores (E-scores), and the self-administered odor questionnaire (SAOQ) were significantly worse in patients who required secondary treatment. A multivariate regression analysis identified age, preoperative CT scores, and 3-month E-scores as predictive factors for secondary treatment. Three-month E-scores showed higher sensitivity and specificity, and the odds ratio was 11.3 when the cut-off value was set at 10.

CONCLUSION

The early identification of patients for whom ESS may fail is important and additional treatments need to be provided at the appropriate timing where needed. Patients with the following factors need to be carefully followed up: a young age, high preoperative CT score, and high early postoperative E-score.

Increased S. aureus colonization and reduced antimicrobial peptide expression in erythrodermic psoriasis

BACKGROUND

Erythrodermic psoriasis (EP) is a severe and rare condition characterized by prominent erythema and scaling over 75 % of the body surface area. Unlike psoriasis vulgaris (PV), EP carries high risk of systemic involvement, including superficial skin infections and sepsis, particularly those caused by Staphylococcus aureus.

OBJECTIVE

To explore the microecological characteristics of EP and detect the levels of antimicrobial peptides (AMPs) in both skin and serum of EP patients.

METHODS

In this study, skin microbiomes of 10 EP patients were analyzed through 16S rRNA gene sequencing. The expressions of AMPs, Interleukin-4/13 (IL-4/13), Interleukin-17 (IL-17) and Interferon-γ (IFN-γ) in skin were detected via immunohistochemical staining and serum levels of AMP were evaluated by ELISA. We also enrolled 10 AD and 10 PV patients as controls.

RESULTS

EP patients retained rich microbial diversity, dominated by S. aureus. The AMPs of hBD2, LL-37, and RNase7 in EP keratinocytes were significantly lower than those in PV, but higher than those in AD. The expression levels of IL-4, IL-13 and IFN-γ in lesions are similar between EP and AD, but quite different from PV. What's more, the serum AMP levels in EP were similar to those in PV while significantly lower than in AD.

CONCLUSION

We found EP patients have a rich microbial diversity dominated by S. aureus in lesions, while lower serum and skin AMPs expressions, which may account for the increased incidence of S. aureus cutaneous infections and sepsis in EP patients.

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.

Oncostatin M's Involvement in the Pathogenesis of Chronic Rhinosinusitis: Focus on Type 1 and 2 Inflammation

OBJECTIVES

The cytokine oncostatin M (OSM) elicits pathogenic effects involving disruption of the epithelial barrier function as a part of immunological response networks. It is unclear how these integrated cytokine signals influence inflammation and other physiological processes in the pathology of chronic rhinosinusitis (CRS). We investigated the expression and distribution of OSM and OSM receptor (OSMR) in CRS patients' sinonasal specimens, and we compared the results with a panel of inflammatory cytokine levels and clinical features.

PATIENTS AND METHODS

We classified CRS patients as eosinophilic (ECRS, n = 36) or non-eosinophilic (non-ECRS, n = 35) based on the Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis phenotypic criteria and compared their cases with those of 20 control subjects. We also examined OSM's stimulatory effects on cytokine receptor expression levels using the human bronchial epithelium cell line BEAS-2B.

RESULTS

RT-PCR showed that the OSM mRNA levels were significantly increased in the CRS patients' ethmoid sinus mucosa. The OSM mRNA levels were positively correlated with those of TNF-α, IL-1β, IL-13, and OSMR-β. In BEAS-2B cells, OSM treatment induced significant increases in the OSMRβ, IL-1R1, and IL-13Ra mRNA levels.

CONCLUSIONS

OSM is involved in the pathogenesis of CRS in both type 1 and type 2 inflammation, suggesting the OSM signaling pathway as a potential therapeutic target for modulating epithelial stromal interactions.

Middle meatus microbiome in patients with eosinophilic chronic rhinosinusitis in a Japanese population

BACKGROUND

Chronic rhinosinusitis (CRS) is a common chronic inflammatory disease and is subdivided into eosinophilic and noneosinophilic forms. There are few reports investigating the nasal microbiome and its pathological functions in patients with CRS.

OBJECTIVE

We sought to analyze factors contributing to variations of the nasal microbiome in CRS, and on the basis of these factors, to elucidate whether the bacterial metabolites were related to the pathogenesis.

METHODS

Nasal swabs were collected, and the V3 to V4 variable region of the 16S ribosomal RNA gene was amplified and sequenced. Factors contributing to variations of the nasal microbiome in patients with CRS were compared. The most influential factor was whether CRS was eosinophilic, and we compared α- and β-diversity, bacterial species, and predictive bacterial functions between the 2 patient groups. In addition, the metabolites of the key bacteria were extracted, and we evaluated the predicted bacterial functions in airway epithelial cells.

RESULTS

In total, 110 patients with CRS and 33 control subjects were enrolled. On the basis of the factors of variation, it was found that patients with eosinophilic CRS (n = 65) had different microbiomes with weighted UniFrac β-diversity and lower α-diversity compared with those with noneosinophilic CRS (n = 45). A higher abundance of Fusobacterium nucleatum and an increased LPS pathway were observed in patients with noneosinophilic CRS compared with those with eosinophilic CRS. In airway epithelial cells, LPS derived from F nucleatum suppressed the expression levels of ALOX15 induced by TH2 cytokines.

CONCLUSIONS

The differences in the nasal microbiome may play a key role in the pathophysiology of CRS.

Integrative analysis of immune-related signature profiles in eosinophilic chronic rhinosinusitis with nasal polyposis

Eosinophilic chronic rhinosinusitis with nasal polyps (ECRSwNP) is a subtype of chronic rhinosinusitis (CRS) that is associated with the nasal cavity and sinus polyps, elevated levels of eosinophils, and dysregulated immune responses to environmental triggers. The underlying cause of ECRSwNP is not well understood, and few studies have focused on the unique features of this subtype of CRS. Our study integrated proteomic and transcriptomic data with multi-omic bioinformatics analyses. We collected nasal polyps from three ECRSwNP patients and three control patients and identified 360 differentially expressed (DE) proteins, including 119 upregulated and 241 downregulated proteins. Functional analyses revealed several significant associations with ECRSwNP, including focal adhesion, hypertrophic cardiomyopathy, and extracellular matrix (ECM)-receptor interactions. Additionally, a protein-protein interaction (PPI) network revealed seven hub proteins that may play crucial roles in the development of ECRSwNP. We also compared the proteomic data with publicly available transcriptomic data and identified a total of 1077 DE genes. Pathways enriched by the DE genes involved angiogenesis, positive regulation of cell motility, and immune responses. Furthermore, we investigated immune cell infiltration and identified biomarkers associated with eosinophil and M2 macrophage infiltration using CIBERSORT and Weighted Gene Correlation Network Analysis (WGCNA). Our results provide a more complete picture of the immune-related mechanisms underlying ECRSwNP, which could contribute to the development of more precise treatment strategies for this condition.

Comprehensive evaluation of type 2 endotype and clinical features in patients with chronic rhinosinusitis with nasal polyps in Taiwan: a cross-sectional study

PURPOSE

Endotype-driven treatment has been introduced in the management of chronic rhinosinusitis with nasal polyps (CRSwNP), and an understanding of the associations between phenotypes and endotypes of CRSwNP will be beneficial in identifying responders. We aimed to determine the correlations between clinical manifestations and type 2 inflammatory mediators of sinonasal tissues.

METHODS

Adult patients undergoing endoscopic sinus surgery for bilateral CRSwNP were prospectively enrolled. Tissue eosinophilia and type 2 mediator expression in tissue homogenates were assessed and correlated with clinical features, including symptoms, comorbidities, blood eosinophil counts, specific allergen immunoglobulin (IgE) testing, computed tomography (CT) scan findings, and Sino-Nasal Outcome Test-22 scores.

RESULTS

A total of 93 subjects were recruited in our study. Fifty-nine (63.4%) cases were identified as the eosinophilic endotype, demonstrating with higher rates of comorbidity of asthma, blood eosinophilia and a high ethmoid-maxillary ratio on CT images. To correlate of phenotypes with the inflammatory mediator profile, multivariate analyses revealed the associations of IgE expression in nasal polyp tissues with allergen sensitization (p = 0.042), CT ethmoid-maxillary ratio (p = 0.001) and tissue eosinophil counts (p = 0.022); the association of interleukin (IL-5) expression with the blood eosinophil percentage (p = 0.020); and the association of IL-13 expression with white blood cell count (p = 0.002) and central compartment-type inflammation (p < 0.001).

CONCLUSION

We demonstrated associations of IgE and IL-5 expression with clinical features of eosinophilic-type inflammation and a significantly elevated level of IL-13 in patients with central-compartment-type CRSwNP. These observations may be useful when considering the use of type 2 biologic treatment and require further validation studies.

Diverse Endotypes of Chronic Rhinosinusitis and Clinical Implications

Chronic rhinosinusitis (CRS) is a highly heterogeneous disease characterized by inflammation in the nasal and sinus mucosa. The CRS phenotypes, based on the presence or absence of nasal polyps, are known as CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). However, this classification has limitations in fully capturing the mechanisms and clinical manifestations of CRS. To address the heterogeneity of CRS, there has been a growing focus on classifying the condition into distinct endotypes. Endotype classification involves grouping patients based on specific molecular, immunological, and clinical characteristics, allowing for more personalized and targeted treatment approaches.This review delves into the current state of endotype classifications for CRS. It explores the role of geographic factors, microbiome, and subphenotype in shaping different endotypes. Additionally, the review examines how various clinical features are associated with specific endotypes, providing valuable insights into tailoring treatment options for better outcomes and transitions between different endotypes.Overall, this review offers a comprehensive and up-to-date perspective on the intricate realm of CRS endotype classifications. By unraveling the molecular and clinical intricacies, this review lays the foundation for more precise, effective, and individualized treatment strategies in the management of CRS.

The Neutralization of the Eosinophil Peroxidase Antibody Accelerates Eosinophilic Mucin Decomposition

Eosinophilic airway inflammation, complicated by bronchial asthma and eosinophilic chronic rhinosinusitis (ECRS), is difficult to treat. The disease may become refractory when eosinophilic mucin associated with eosinophil peroxidase (EPX) and autoantibodies fills in the paranasal sinus and small airway. This study investigated the functional role of an anti-EPX antibody in eosinophilic mucin of ECRS in eosinophilic airway inflammation. Eosinophilic mucin was obtained from patients with ECRS. The effects of the anti-EPX antibody on dsDNA release from eosinophils and eosinophilic mucin decomposition were evaluated. Immunofluorescence or enzyme-linked immunosorbent assays were performed to detect the anti-EPX antibody and its supernatant and serum levels in eosinophilic mucin, respectively. The serum levels of the anti-EPX antibody were positively correlated with sinus computed tomography score and fractionated exhaled nitrogen oxide. Patients with refractory ECRS had higher serum levels of the anti-EPX antibody than those without. However, dupilumab treatment decreased the serum levels of the anti-EPX antibody. Immunoglobulins (Igs) in the immunoprecipitate of mucin supernatants enhanced dsDNA release from eosinophils, whereas the neutralization of Igs against EPX stopped dsDNA release. Furthermore, EPX antibody neutralization accelerated mucin decomposition and restored corticosteroid sensitivity. Taken together, the anti-EPX antibody may be involved in the formulation of eosinophilic mucin and be used as a clinical marker and therapeutic target for intractable eosinophilic airway inflammation.

Exhaled Nitric Oxide and Olfactory Dysfunction in Patients with Asthma: Association with Chronic Rhinosinusitis

Objectives: Olfactory dysfunction is a clinical sign that is important to detect with coexistent upper airway comorbidities in patients with asthma. This study aimed to investigate the etiology of olfactory dysfunction in patients with asthma and the relationship between fractional exhaled nitric oxide (FeNO) levels. Materials and Methods: This study included 47 asthma patients who were evaluated for olfactory dysfunction at Hiroshima University Hospital between 2012 and 2020. The etiologies of olfactory dysfunction were evaluated, and they were classified according to the FeNO levels of patients with asthma. Results: Olfactory dysfunction was observed in 30 patients with asthma, with chronic rhinosinusitis (77%) being the most prevalent etiology. Eosinophilic chronic rhinosinusitis (ECRS) was the most prevalent etiology of olfactory dysfunction in asthma patients with high FeNO levels (≥25 ppb), while non-eosinophilic chronic rhinosinusitis (NCRS) was the most prevalent etiology in asthma patients with low FeNO levels (<25 ppb). Additionally, the prevalence of ECRS was significantly higher in asthma patients with olfactory dysfunction and high FeNO levels (74%) than in those with either high FeNO levels or olfactory dysfunction and those with low FeNO levels and no olfactory dysfunction (12% and 9%, respectively). Conclusions: We found that ECRS was the predominant cause of olfactory dysfunction in patients with high FeNO levels, while NCRS was more common in those with low FeNO levels. The present study showed that both ECRS and NCRS are common etiologies of olfactory dysfunction in patients with asthma. Additionally, this study supports the link between upper and lower airway inflammation in patients with asthma complicated with olfactory dysfunction.

Relationship of Lesion Location to Postoperative Steroid Use in Eosinophilic Chronic Rhinosinusitis

OBJECTIVES

Eosinophilic chronic rhinosinusitis (ECRS) is known to recur after surgery. The treatment choice for recurrent ECRS, such as oral steroids or biological agents, must be chosen carefully, and identifying the lesion location may be useful. This study aimed to evaluate the postoperative course of ECRS patients and assess the relationship between endoscopic lesion location and postoperative oral steroid use.

METHODS

Patients with chronic rhinosinusitis who underwent bilateral endoscopic sinus surgery from April 2018 to March 2020 were divided into two groups based on the presence or absence of oral steroid use after surgery. The primary endpoint was the lesion location on endoscopic findings during surgery: middle turbinate, middle meatus, superior turbinate, superior meatus, nasal septum, and sphenoethmoidal recess. Subjective symptoms, blood tests, and computerized tomography (CT) findings (Lund-Mackay score) were evaluated as secondary endpoints.

RESULTS

Among 264 patients, 88 were diagnosed histologically with ECRS (mean 48.98 ± 1.40 years, 67 males/21 females). Twenty-three patients were steroid-using, 65 were steroid-free, and six stopped attending their appointments. Patients with sphenoethmoidal recess lesions were significantly more likely to require steroids (p = 0.019). There was a significant association between steroid use and younger age (p = 0.041), olfactory dysfunction (p = 0.021), and all sinuses (Frontal sinus: p < 0.001, Anterior ethmoid sinus: p = 0.002, Posterior ethmoid sinus: p = 0.011, Maxillary sinus: p = 0.018, Sphenoid sinus: p = 0.034, Total score: p < 0.001).

CONCLUSION

A sphenoethmoidal recess lesion was a risk factor for requiring postoperative steroids. Young age, olfactory dysfunction, and preoperative severe CT findings were also significant risk factors.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:2511-2516, 2023.

The interplay of inflammation and remodeling in the pathogenesis of chronic rhinosinusitis: current understanding and future directions

Chronic rhinosinusitis (CRS), a common clinical condition characterized by persistent mucosal inflammation and tissue remodeling, has a complex pathogenesis that is intricately linked to innate and adaptive immunity. A number of studies have demonstrated that a variety of immune cells and cytokines that play a vital role in mediating inflammation in CRS are also involved in remodeling of the nasal mucosa and the cells as well as different cytokines involved in remodeling in CRS are also able to exert some influence on inflammation, even though the exact relationship between inflammation and remodeling in CRS has not yet been fully elucidated. In this review, the potential role of immune cells and cytokines in regulating inflammation and remodeling of CRS mucosa has been described, starting with the immune cells and cytokines that act together in inflammation and remodeling. The goal is to aid researchers in understanding intimate connection between inflammation and remodeling of CRS and to offer novel ideas for future research.

Vitamin D Levels in Chronic Rhinosinusitis in Patients With or Without Nasal Polyposis: A Systematic Review

Chronic rhinosinusitis (CRS) is a large group of heterogeneous diseases characterized by extensive inflammation of the nasal mucosa and sinuses. Vitamin D (VD), as an immunoregulatory hormone, may play an important role in the pathophysiology of CRS. The purpose of this study is to review the existing literature that correlates VD levels with CRS with or without nasal polyps. A systematic manual search was conducted in the PubMed and Google Scholar databases up to July 2023. Articles from PubMed and the first 100 articles from Google Scholar were recorded for our research. Keywords used were the following: vitamin D, chronic rhinosinusitis, and nasal polyps. Among the 134 articles retrieved, only 18 were eligible. The other 116 studies were excluded as they related VD levels with other conditions (e.g., allergic rhinitis) and for other reasons. However, we identified two more eligible records through the manual research of the above-mentioned 132 studies, and finally, 20 records were included in the current review. The review concerned case-control studies, prospective, retrospective, and cross-sectional studies. Based on our review, we concluded that CRS patients are correlated with the lowest VD levels, accompanied by increased severity of the disease, especially in those with nasal polyposis. Patients can benefit from appropriate VD supplementation, and serum VD levels should be included in the laboratory assessment of CRS. However, due to the heterogeneity of the individuals involved, more well-designed clinical trials as well as randomized clinical trials should be conducted for further validation of the above findings in the general population in the future.

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.

Novel insights into central compartment atopic disease - a literature review

INTRODUCTION

Central compartment atopic disease (CCAD) is a newly recognized variant subtype of chronic rhinosinusitis (CRS). Although CCAD has been reported to be correlated with allergy, there is still a considerable gap in our knowledge regarding CCAD.

AREAS COVERED

We have conducted a thorough analysis of the literature on CCAD. This review provides current understanding and therapeutic strategies of CCAD. In this article, we will review the clinical presentations and parameters, allergy-related etiology, endotypes, and recommended management of CCAD.

EXPERT OPINION

CCAD is considered as an aeroallergen-driven type 2/eosinophilic inflammatory pattern. Although CCAD can be diagnosed by endoscopy and radiology, as well as allergen test, pathogenesis and management strategies leave much to be desired, and further studies are needed.

The functional role and the clinical application of periostin in chronic rhinosinusitis

INTRODUCTION

Chronic rhinosinusitis (CRS) comprises several heterogenous groups, now classified based on endotype more often than on phenotype. A number of studies aimed at finding a useful biomarker for type 2 CRS suggest that periostin is a promising surrogate.

AREAS COVERED

A comprehensive overview of the clinical significance of tissue periostin expression and serum periostin in CRS patients is provided. The effects of comorbid asthma on serum periostin and samples other than serum in which periostin can be detected in CRS patients are also discussed. Moreover, the functional roles of periostin in CRS pathogenesis are summarized.

EXPERT OPINION

The position of periostin as a signature biomarker of type 2 CRS has been well established, enabling us to classify CRS patients by endotyping. Serum periostin is useful not only for endotyping CRS patients, but also for estimating disease severity, comorbidity, prognosis, and response to treatment, and in particular, predicting recurrence after surgery. However, it remains to be addressed how we apply serum periostin to using biologics for CRS patients. Further studies aimed at showing periostin to be a therapeutic target for CRS are awaited.