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

Multi-omics integration and machine learning identify and validate neutrophil extracellular trap-associated gene signatures in chronic rhinosinusitis with nasal polyps

This study aimed to explore the molecular characteristics of neutrophil extracellular traps (NETs) in chronic rhinosinusitis with nasal polyps (CRSwNP). Differentially expressed gene analysis, weighted gene co-expression network analysis, and machine learning algorithms identified three core NETs-associated genes: CXCR4, CYBB, and PTAFR, which were significantly upregulated in CRSwNP patients. The diagnostic performance of these genes was evaluated using receiver operating characteristic (ROC) curves, and their clinical relevance was validated using multicenter data. Immune infiltration analysis showed strong correlations between these genes and neutrophil and immune cell infiltration. Single-cell RNA sequencing demonstrated that these genes were predominantly expressed in myeloid and immune cells and exhibited dynamic changes during disease progression. These genes may contribute to CRSwNP pathogenesis through IL-17 signaling and metabolism-related pathways. This study identifies novel biomarkers and therapeutic targets for precise diagnosis and personalized treatment of CRSwNP.

Clinical and mechanistic advancements in aspirin exacerbated respiratory disease

Aspirin-exacerbated respiratory disease (AERD) is characterized by the clinical triad of chronic rhinosinusitis with nasal polyps, asthma, and a hypersensitivity to nonsteroidal anti-inflammatory drugs (NSAIDs). AERD is estimated to occur in as many as 15% of patients with chronic rhinosinusitis with nasal polyps and/or asthma. Uniquely, patients with AERD develop respiratory symptoms within 30 to 180 minutes after ingesting NSAIDs such as aspirin or ibuprofen. However, even in the absence of NSAIDs, patients tend to have more severe upper and lower respiratory disease. The underlying pathogenic mechanisms contributing to AERD are complex and intertwined; they include a systemic dysregulation in arachidonic acid metabolism, an aberrant inflammatory response, a disruption in the respiratory epithelial barrier, and an imbalance between the formation and degradation of fibrin locally in nasal polyps. This review will highlight novel mechanistic findings contributing to the pathogenesis of AERD. In addition, recent advancements in the clinical understanding and management of patients with AERD will be discussed.

Expression of Alpha-Smooth Muscle Actin in Nasal Polyp Tissue of Chronic Rhinosinusitis Patients With and Without Aspirin Hypersensitivity

BACKGROUND

Previous research has shown that myofibroblasts in the nasal/sinus mucosa are not only structural cells but also a rich source of inflammatory mediators. Thus, they influence the immune response and play an essential role in the pathogenesis of chronic rhinosinusitis with nasal polyposis. Previous research did not provide a clear answer to the question of whether the number of myofibroblasts in nasal polyps (NPs) affects the extent of sinus disease. This cross-sectional study investigates the relationship between the number of active myofibroblasts, eosinophil count, and clinical parameters in patients with NPs with and without aspirin sensitivity.

METHODS

Patients diagnosed with NPs, with and without aspirin sensitivity, and healthy subjects were assessed according to the severity of their symptoms as well as endoscopic and radiological findings. The quantification of myofibroblasts present in the surgically excised polyp tissue/healthy nasal mucosa was conducted based on the expression of alpha-smooth muscle actin (α-SMA) in the subepithelial and perivascular compartments. Eosinophils were counted in the subepithelium of the tissue samples from all subjects.

RESULTS

Forty-nine subjects were included: 23 NP patients without, 14 NP patients with aspirin sensitivity, and 12 control participants. The highest levels of α-SMA expression and eosinophil count were observed in NP patients with aspirin sensitivity and the lowest in healthy subjects (P < .001; P < .001, respectively). A strong correlation was noted between α-SMA expression and clinical parameters, particularly with disease extent evaluated radiologically and endoscopically.

CONCLUSION

Our results suggest a positive correlation between the quantity of myofibroblasts and the severity of chronic inflammation in the sinonasal region. The number of myofibroblasts in the NP tissue may serve as a reliable marker for assessing the clinical status of the disease.

Histopathologic features of chronic rhinosinusitis with nasal polyps in patients from high-altitude Xizang region

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a heterogeneous inflammatory disease with varying patterns across regions.

OBJECTIVE

This study aims to investigate the clinical and histopathological features of CRSwNP in Xizang, a high-altitude region in China.

MATERIALS AND METHODS

We retrospectively analyzed the histopathological features of CRSwNP patients from Shanghai and Xizang who underwent functional endoscopic sinus surgery (FESS) between 2017 and 2024. Polyp tissue samples were assessed, and statistical analyses compared features between the two regions in CRSwNP, eosinophilic CRSwNP (eCRSwNP), and noneosinophilic CRSwNP (neCRSwNP) patients.

RESULTS

Twenty-eight patients from Xizang and 35 from Shanghai were analyzed. All Shanghai patients were Han Chinese, and all Xizang patients were Tibetan. Compared to Shanghai, Tibetan patients had significantly lower rates of smoking and asthma. Overall inflammation levels in Xizang were lower, while eosinophil counts were lower in eCRSwNP patients. Neutrophil infiltration, mucosal ulceration, and squamous metaplasia were higher in Xizang patients, while neCRSwNP patients exhibited more neutrophil infiltration and less subepithelial edema.

CONCLUSIONS

The study revealed that Tibetan patients with CRSwNP have lower eosinophilic inflammation but higher neutrophil infiltration and squamous metaplasia compared to Shanghai patients, indicating the impact of high-altitude environments on inflammatory patterns.

IL-25 Enhances B Cell Responses in Type 2 Inflammation Through IL-17RB Receptor

BACKGROUND

Alarmin cytokine IL-25 promotes type 2 inflammatory responses in disorders such as asthma and chronic rhinosinusitis with nasal polyps (CRSwNP) and known targets include ILC2 and Th2 cells. However, other cellular targets for IL-25 remain poorly defined.

OBJECTIVE

To investigate induction and expression of IL-25 receptor (IL-17RB) by B cells and evaluate responsiveness of IL-17RB-expressing B cells to IL-25 in vitro.

METHODS

IL-17RB expression, regulation and function on B cells were evaluated in peripheral blood-derived B cells by flow cytometry and RT-PCR, including in response to IgE-inducing stimuli (anti-CD40 mAb and IL-4). Single-cell RNA sequencing was used to compare IL-17RB+ and IL-17RB-activated peripheral blood-derived B cells. To evaluate B cell IL-17RB expression within type 2 inflamed tissue, B cells were compared from nasal polyps, control turbinate tissue and matched peripheral blood.

RESULTS

Activation of B cells with anti-CD40 and IL-4 increased IL-17RB expression at both protein and mRNA level, which was further upregulated by IL-25. B cells induced to express IL-17RB responded to IL-25 with enhanced antibody production. Single-cell RNA-sequencing showed that IL17RB+ activated B cells expressed higher levels of IGHE, CCL17 and CCL22 compared to IL17RB- B cells. B cells from nasal polyp tissue expressed higher levels of surface IL-17RB compared with control tissue, correlating with patient-reported CRSwNP severity (SNOT-22).

CONCLUSION

Peripheral blood B cells activated under IgE-inducing conditions express surface IL-17RB, and tissue IL-17RB+ B cells are increased in type 2 inflammation. IL-17RB+ cells have a distinct transcriptional profile and respond to IL-25 with enhanced antibody production, highlighting the IL-25/IL-17RB pathway as a potential therapeutic target for CRSwNP and other type 2 inflammatory disorders.

How does asthma coexistence affect the strategic selection of biologic therapies in CRSwNP management?

Objectives

We reviewed asthma coexistence and the selection of biologic therapies in CRSwNP Management.

Methods

The literature review utilized Google and Google Scholar, in addition to PubMed, EBSCO, and Proquest Central at Kırıkkale University. We searched for " CRSwNP", "asthma", "biologic therapies", "Anti-IL-4RA", "Dupilumab", "Anti-IgE", "Omalizumab", "Anti-IL-5", "mepolizumab" from 2024 to 2000.

Results

Patients with CRSwNP frequently have co-occurring lower airway illnesses, including asthma and AERD asthma, which have a shared pathogenesis. The inflammatory bases of CRSwNP and asthma might be heterogeneous, with a type 2 or, less frequently, a non-type two inflammatory history. Lower airway inflammation and asthma control are worse in patients with asthma who also have CRSwNP. Patients with CRSwNP can now access targeted biologic medicines, a novel therapy option. The US Food and Drug Administration (FDA) has authorized three medications for CRSwNP: dupilumab, omalizumab, and mepolizumab. To treat chronic rhinosinusitis with a biological agent, the 2020 European position paper on rhinosinusitis established clear indications. A patient is considered a biologic therapy candidate if they have either undergone FESS before or did not meet FESS criteria but met three of the five. A diagnosis of concomitant asthma, necessitating an inhaled glucocorticoid controller regularly, is one of the five requirements.

Conclusion

Biologic treatments have the potential to be used in certain patients where CRSwNP and asthma coexist. The recommended treatments include omalizumab, dupilumab, and mepolizumab.

Tezepelumab in Adults with Severe Chronic Rhinosinusitis with Nasal Polyps

BACKGROUND

Treatment with tezepelumab has been effective for sinonasal symptoms in patients with severe, uncontrolled asthma and a history of chronic rhinosinusitis with nasal polyps, but its efficacy and safety in adults with severe, uncontrolled chronic rhinosinusitis with nasal polyps is unknown.

METHODS

We randomly assigned adults with physician-diagnosed, symptomatic, severe chronic rhinosinusitis with nasal polyps to receive standard care and either tezepelumab (at a dose of 210 mg) or placebo subcutaneously every 4 weeks for 52 weeks. The coprimary end points were the changes from baseline in the total nasal-polyp score (range, 0 to 4 [for each nostril]; higher scores indicate greater severity) and the mean nasal-congestion score (range, 0 to 3; higher scores indicate greater severity) at week 52. Key secondary end points assessed in the overall population were the loss-of-smell score, the total score on the Sinonasal Outcome Test (SNOT-22; range, 0 to 110; higher scores indicate greater severity), the Lund-Mackay score (range, 0 to 24; higher scores indicate greater severity), the total symptom score (range, 0 to 24; higher scores indicate greater severity), and the first decision to treat with nasal-polyp surgery or use of systemic glucocorticoid therapy, or both, assessed in time-to-event analyses (individual and composite).

RESULTS

In total, 203 patients were assigned to receive tezepelumab and 205 to receive placebo. At week 52, the patients who received tezepelumab had significant improvements in the total nasal-polyp score (mean difference vs. placebo, -2.07; 95% confidence interval [CI], -2.39 to -1.74) and the mean nasal-congestion score (-1.03; 95% CI, -1.20 to -0.86) (P<0.001 for both scores). Tezepelumab significantly improved the loss-of-smell score (mean difference vs. placebo, -1.00; 95% CI, -1.18 to -0.83), SNOT-22 total score (-27.26; 95% CI, -32.32 to -22.21), Lund-Mackay score (-5.72; 95% CI, -6.39 to -5.06), and total symptom score (-6.89; 95% CI, -8.02 to -5.76) (P<0.001 for all scores). Surgery for nasal polyps was indicated in significantly fewer patients in the tezepelumab group (0.5%) than in the placebo group (22.1%) (hazard ratio, 0.02; 95% CI, 0.00 to 0.09); there was significantly less use of systemic glucocorticoids with tezepelumab (5.2%) than with placebo (18.3%) (hazard ratio, 0.12; 95% CI, 0.04 to 0.27) (P<0.001 for both time-to-event analyses).

CONCLUSIONS

Tezepelumab therapy led to significantly greater reductions in the size of nasal polyps, the severity of nasal congestion and sinonasal symptoms, and the use of nasal-polyp surgery and systemic glucocorticoids than placebo in adults with severe, uncontrolled chronic rhinosinusitis with nasal polyps. (Funded by AstraZeneca and Amgen; WAYPOINT ClinicalTrials.gov number, NCT04851964.).

The Association of TSLP and IL-4 with Patient-Reported Outcome Measures in Chronic Rhinosinusitis with Nasal Polyps

BACKGROUND

Thymic stromal lymphopoietin (TSLP) plays an important role in mediating the type-2-inflammatory response. This study examined how TSLP and interleukin (IL)-4 levels in patients with chronic rhinosinusitis with nasal polyps (CRSwNP) correlated with clinical and postoperative outcomes.

METHODS

Solid-phase sandwich ELISA was used to analyze TSLP and IL-4 levels in mucus (n = 47), plasma (n = 17), polyp (n = 30), inferior (n = 25), and middle (n = 26) turbinate tissue collected during functional endoscopic sinus surgery (FESS) in CRSwNP patients (n = 76) and controls (n = 11). Inclusion criteria includes patients with medical treatment refractory CRSwNP confirmed by endoscopy or maxillofacial CT. Exclusion criteria include history of immunodeficiency, coagulation disorders, fungal sinusitis, or cystic fibrosis. Levels of TSLP and IL-4 were correlated with SNOT-22, UPSIT, and fractional exhaled nitric oxide (FeNO) using MannWhitney U two-tailed test and linear regression with Spearman correlation coefficient test.

RESULTS

TSLP is elevated in the inferior turbinates (effect size = 2.695, p = 0.0007) of CRSwNP patients compared to controls. IL-4 is expressed at elevated levels in the inferior (effect size = 3.092, p < 0.0001) and middle turbinates (effect size = 2.041, p = 0.019) compared to controls. Mucus TSLP (r = 0.4013, p = 0.0153) and IL-4 (r = 0.6138, p < 0.0001) positively correlate with preoperative FeNO levels. Lower TSLP in the inferior (r = -0.5179, p = 0.0231) and middle turbinates (r = -0.5075, p = 0.0224) and lower IL-4 in the inferior turbinates (r = -0.5205, p = 0.0223) correlate with a greater improvement in SNOT-22 post-FESS.

CONCLUSION

TSLP and IL-4 are elevated in patients with CRSwNP and correlated with increased preoperative FeNO levels and decreased sinonasal quality of life benefit after FESS. Expression of TSLP and IL-4 may play a role in guiding postoperative expectations in patients with treatment refractory CRSwNP.

HMOX1 as a potential drug target for upper and lower airway diseases: insights from multi-omics analysis

BACKGROUND

Oxidative stress is key in inflammatory airway diseases. Heme oxygenase 1 (HMOX1) regulates oxidative stress, but its role in airway diseases needs exploration.

METHODS

Differentially expressed genes (DEGs) between healthy nasal mucosa and chronic rhinosinusitis with nasal polyps (CRSwNP) were identified from Gene Expression Omnibus (GEO). Candidate genes were further screened using Gene Set Enrichment Analysis (GSEA) and Random Forest (RF) algorithms. Causal inference between candidate genes and upper and lower airway diseases (CRSwNP, allergic rhinitis (AR), and asthma (AS)) was conducted using bidirectional two-sample Mendelian randomization (TwoSampleMR) analysis. Single-cell RNA sequencing (scRNA-seq) data were used to determine the cellular localization and intercellular interactions of candidate genes. Molecular docking was used to identify potential therapeutic agents.

RESULTS

HMOX1 expression was significantly elevated in CRSwNP. TwoSampleMR analysis indicated a negative causal relationship between HMOX1 exposure and the occurrence of upper and lower airway diseases (CRSwNP [(odds ratio (OR)/95% confidence interval (CI): 0.945/(0.893-0.999), P = 0.044], AR [OR/95% CI: 0.997/(0.994-0.999), P = 0.007], and AS [OR/95% CI: 0.935/(0.895-0.977), P = 0.003]). scRNA-seq data revealed HMOX1 localization in M2 macrophages. Molecular docking identified 15 antioxidants, including Acetylcysteine and Quercetin, that can upregulate HMOX1 expression.

CONCLUSION

HMOX1 may have a protective role in the pathogenesis of upper and lower airway diseases (CRSwNP, AR, and AS) by modulating oxidative stress. Antioxidants that increase HMOX1 expression could offer new therapeutic avenues for these diseases.

CLINICAL TRIAL

Not applicable.

Human intraepithelial mast cell differentiation and effector function are directed by TGF-β signaling

Mast cells (MCs) expressing a distinctive protease phenotype (MCTs) selectively expand within the epithelium of human mucosal tissues during type 2 (T2) inflammation. While MCTs are phenotypically distinct from subepithelial MCs (MCTCs), signals driving human MCT differentiation and this subset's contribution to inflammation remain unexplored. Here, we have identified TGF-β as a key driver of the MCT transcriptome in nasal polyps. We found that short-term TGF-β signaling alters MC cell surface receptor expression and partially recapitulated the in vivo MCT transcriptome, while TGF-β signaling during MC differentiation upregulated a larger number of MCT-associated transcripts. TGF-β inhibited the hallmark MCTC proteases chymase and cathepsin G at both the transcript and protein level, allowing selective in vitro differentiation of MCTs for functional study. We identified discrete differences in effector phenotype between in vitro-derived MCTs and MCTCs, with MCTs exhibiting enhanced proinflammatory lipid mediator generation and a distinct cytokine, chemokine, and growth factor production profile in response to both innate and adaptive stimuli, recapitulating functional features of their tissue-associated counterpart MC subsets. Thus, our findings support a role for TGF-β in promoting human MCT differentiation and identified a discrete contribution of this cell type to T2 inflammation.

Critical pathomechanisms of NSAID-exacerbated respiratory disease (N-ERD) clarified by treatment with omalizumab, an anti-IgE antibody

Characteristic symptoms of NSAID-exacerbated respiratory disease (N-ERD) include asthma, chronic eosinophilic rhinosinusitis with nasal polyposis, cysteinyl LT (CysLT) overproduction and NSAIDs hypersensitivity. Some N-ERD patients present with episodic treatment-resistant extra-respiratory symptoms (CysLT-associated coronary artery vasospasm, gastroenteritis, or skin rash). Even when using standard treatments for respiratory and extra-respiratory symptoms, including systemic corticosteroids and aspirin desensitization, it is difficult to control the clinical symptoms and severe type 2 inflammation involved with mast cells, eosinophils, ILC2s, and platelet activation. Few treatment options are applicable in a clinical setting. Therefore, identifying effective treatments is essential for managing N-ERD patients who suffer from these conditions. Our previous observational study demonstrated 12-month omalizumab treatment of N-ERD was clinically effective against respiratory symptoms. Despite the remaining eosinophilia, omalizumab significantly reduced urinary LTE4 and PGD2 metabolites to near normal levels at steady state. Based on the preliminary study, we demonstrated that omalizumab induced tolerance to aspirin in N-ERD patients 3 months after therapy initiation and suppressed activation of mast cells during 24 h of initiation in a randomized manner. Moreover, omalizumab had significant efficacy against extra-respiratory symptoms at baseline (lacking aspirin exposure) as well as throughout aspirin challenge. This review addresses the latest discoveries related to N-ERD pathogenesis and the significant effectiveness of omalizumab on N-ERD as a mast cell stabilizer. Our findings regarding omalizumab-associated mast cell inhibitory effects are indirect evidence that mast cell dysregulation and, possibly, IgE are pivotal components of N-ERD.

European biologic training course for type 2 inflammation by EUFOREA in 2024: key facts and lessons learned

The European Forum for Research and Education in Allergy and Airways diseases (EUFOREA) organized the first European Biologic Training Course (EBTC) in Brussels on 1st March 2024. The aim of this hybrid EBTC including both face-to-face and web-based participation was to address the educational needs of physicians dealing with asthma and Chronic Rhinosinusitis with Nasal Polyps (CRSwNP) on the clinically relevant aspects of diagnosing and treatment with biologics. EUFOREA is an international non-for-profit organization forming an alliance of all stakeholders dedicated to reducing the prevalence and burden of chronic respiratory diseases through the implementation of optimal patient care via educational, research, and advocacy activities. The inclusive and multidisciplinary approach of EUFOREA was reflected in faculty coming from the paediatric, allergology, pulmonology, and Ear, Nose and Throat (ENT) speciality and from different continents, with more than 250 participants from over 30 countries in the first EBTC. The current report provides a comprehensive overview of key statements made by the faculty of the EBTC 2024, especially focusing on patient selection for a biologic drug, the communication with patients, the onset of biological treatment and the follow-up in routine clinical practice.

Spatial adaptation of eosinophils and their emerging roles in homeostasis, infection and disease

Eosinophils are bone marrow-derived granulocytes that are traditionally associated with type 2 immune responses, such as those that occur during parasite infections and allergy. Emerging evidence demonstrates the remarkable functional plasticity of this elusive cell type and its pleiotropic functions in diverse settings. Eosinophils broadly contribute to tissue homeostasis, host defence and immune regulation, predominantly at mucosal sites. The scope of their activities primarily reflects the breadth of their portfolio of secreted mediators, which range from cytotoxic cationic proteins and reactive oxygen species to multiple cytokines, chemokines and lipid mediators. Here, we comprehensively review basic eosinophil biology that is directly related to their activities in homeostasis, protective immunity, regeneration and cancer. We examine how dysregulation of these functions contributes to the physiopathology of a broad range of inflammatory diseases. Furthermore, we discuss recent findings regarding the tissue compartmentalization and adaptation of eosinophils, shedding light on the factors that likely drive their functional diversification within tissues.

Nonsteroidal antiinflammatory drug-exacerbated respiratory disease: molecular mechanism, management and treatment

It has been estimated that Nonsteroidal Anti-inflammatory drug (NSAID) Exacerbated Respiratory Disease (N-ERD) previously named as Aspirin Exacerbated Respiratory Disease (A-ERD) affects around 1.4 million persons in the United States. Its prevalence in asthmatic patients has widely been underestimated, as a considerable number of patients would need an aspirin provocation test to confirm the diagnosis. N-ERD physiopathology is somehow complex, but basically involves an imbalance in the arachidonic acid metabolite pathway. The syndrome is characterized by the presence of asthma, chronic rhinosinusitis with nasal polyposis (CRSwNP) and NSAID and aspirin intolerance. Despite maximal and comprehensive medical treatment, the disease tends to be severe, with difficult to treat asthma and highly aggressive and recurrent ethmoidal polyposis. Recently, monoclonal antibodies aimed at reducing type 2 inflammation have demonstrated very promising results on disease control. The goal of this review is to provide the most recent published advances and evidence on physiopathology, diagnostic protocols and therapeutic strategies of N-ERD.

Perıostın and fıbronectın ın nasal lesıons: key players ın polyps and ınverted papıllomas

Background

Sinonasal lesions are common benign masses with overlapping clinical and histopathological features. Extracellular matrix proteins such as periostin, fibronectin, and tenascin-C play key roles in tissue remodeling and inflammation, yet their distinct expression profiles in these lesions remain poorly defined.

Aim

This study aimed to compare the immunohistochemical staining patterns of periostin, fibronectin, and tenascin-C in sinonasal lesions to elucidate their roles in pathogenesis and enhance differential diagnosis.

Methods

In this retrospective study, pathological specimens from 70 patients who underwent surgery for sinonasal polyps were analyzed. Immunohistochemical expression of periostin, fibronectin, and tenascin-C was assessed separately in epithelial and stromal compartments using a semi-quantitative scoring system. Associations between staining patterns and lesion types were evaluated using multinomial logistic regression.

Results

The cohort had a male-to-female ratio of 5:2 with a mean age of approximately 40 years. Nasal polyps demonstrated significantly higher stromal periostin staining compared to both antrochoanal polyps and inverted papillomas. Conversely, antrochoanal polyps exhibited significantly elevated epithelial periostin expression relative to inverted papillomas. Fibronectin expression was markedly increased in nasal polyps, especially in the stroma, supporting its role in inflammatory tissue remodeling. Tenascin-C expression did not differ significantly among the lesion types.

Conclusion

Differential expression of periostin and fibronectin suggests distinct pathogenic mechanisms in sinonasal lesions. The compartment-specific staining patterns of periostin, along with the prominent fibronectin expression in nasal polyps, suggest these biomarkers could serve as valuable diagnostic tools and potential therapeutic targets. Further research is needed to explore these pathways in sinonasal disease management.

Integrated machine learning and bioinformatic analysis of mitochondrial-related signature in chronic rhinosinusitis with nasal polyps

Background

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a prevalent inflammatory disorder affecting the upper respiratory tract. Recent studies have indicated an association between CRSwNP and mitochondrial metabolic disorder characterized by impaired metabolic pathways; however, the precise mechanisms remain unclear. This study aims to investigate the mitochondrial-related signature in individuals diagnosed with CRSwNP.

Methods

Through the integration of differentially expressed genes (DEGs) with the mitochondrial gene set, differentially expressed mitochondrial-related genes (DEMRGs) were identified. Subsequently, the hub DEMRGs were selected using 4 integrated machine learning algorithms. Immune and mitochondrial characteristics were estimated based on CIBERSORT and ssGSEA algorithms. Bioinformatic findings were confirmed through RT-qPCR, immunohistochemistry, and ELISA for nasal tissues, as well as Western blotting analysis for human nasal epithelial cells (hNECs). The relationship between hub DEMRGs and disease severity was assessed using Spearman correlation analysis.

Results

A total of 24 DEMRGs were screened, most of which exhibited lower expression levels in CRSwNP samples. Five hub DEMRGs (ALDH1L1, BCKDHB, CBR3, HMGCS2, and OXR1) were consistently downregulated in both the discovery and validation cohorts. The hub genes showed a high diagnostic performance and were positively correlated with the infiltration of M2 macrophages and resting mast cells. Experimental results confirmed that the 5 genes were downregulated at both the mRNA and protein levels within nasal polyp tissues. Finally, a significant and inverse relationship was identified between the expression levels of these genes and both the Lund-Mackay and Lund-Kennedy scores.

Conclusion

Our findings systematically unraveled 5 hub markers correlated with mitochondrial metabolism and immune cell infiltration in CRSwNP, suggesting their potential to be based to design diagnostic and therapeutic strategies for the disease.

Increased autoreactivity and maturity of EBI2+ antibody-secreting cells from nasal polyps

Elevated numbers of antibody-secreting cells (ASCs) and anti-double-stranded DNA (anti-dsDNA) antibodies are found in nasal polyp (NP) tissue. The presence of anti-dsDNA IgG in tissue prospectively predicts recurrent NP but the characteristics of the source ASCs are unknown. Here, we investigated whether NP B cells expressing the extrafollicular marker EBI2 have increased propensity for autoantibody production and evaluated the molecular characteristics of NP ASCs. NPs showed increased frequencies of anti-dsDNA IgG and total IgG ASCs compared with tonsils, with more pronounced differences among EBI2+ cells. In NPs, EBI2+ cells were frequently double negative (IgD-CD27-) and ASCs. Single-cell RNA-Seq analysis of tonsils and NPs revealed substantial differences in B lineage composition, including differences in percentages of ASCs, germinal centers, proliferative cells, and non-ASCs. NPs exhibited higher expression of specific isotypes (IGHE, IGHA1, IGHA2, and IGHG4) and mature plasma genes, including SDC1 and XBP1, than tonsils. Gene Ontology biological processes indicated upregulated NF-κB and downregulated apoptosis pathways in NP ASCs. Together, these data indicate that NP EBI2+ ASCs secret increased total and anti-dsDNA IgG compared with those from tonsils and had molecular features of mature plasma cell differentiation.

Identification of hub genes associated with neutrophils in chronic rhinosinusitis with nasal polyps

Neutrophil infiltration plays a key role in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP). However, pertinent mechanisms remain poorly elucidated. Here, we obtained the data from gene expression omnibus (GEO) and gene set enrichment analysis (GSEA) to identify and validate neutrophil-associated hub genes in CRSwNP. We found that four neutrophil-associated hub genes, namely ICAM1, IL-1β, TYROBP, and BCL2A1, were markedly upregulated and positively correlated with neutrophil infiltration levels in patients with CRSwNP. Subsequently, this was confirmed by real-time quantitative PCR. In conclusion, we identified the role of neutrophil infiltration in the pathophysiology of CRSwNP, which may be the potential targets for the diagnosis and treatment of CRSwNP.

Relief of Airflow Limitation and Airway Inflammation by Endoscopic Sinus Surgery in a Patient with Severe Asthma with Eosinophilic Chronic Rhinosinusitis

Although endoscopic sinus surgery (ESS) is beneficial in improving asthma symptoms, its impact on the lung function in patients with asthma and chronic rhinosinusitis remains unclear. We herein report a case of severe asthma with eosinophilic chronic rhinosinusitis, in which ESS substantially improved airflow limitation and concomitantly reduced fractional exhaled nitric oxide and blood eosinophil counts. ESS likely relieved airflow limitation by suppressing type 2 inflammatory pathways. This case highlights ESS as a promising strategy for achieving clinical remission in patients with severe asthma and chronic rhinosinusitis.

Inflammatory Cytokines in Middle Ear Effusion of Patients With Asthma, Chronic Rhinosinusitis With Nasal Polyps With or Without NSAID Intolerance

OBJECTIVE

To measure the inflammatory cytokines of middle ear effusion (MEE) in otitis media (OM) associated with asthma and chronic rhinosinusitis with nasal polyps (CRSwNP) with or without nonsteroidal anti-inflammatory drug (NSAID) sensitivity to strengthen our assumption that OM is part of the same inflammatory entity. The potential individual differences between MEE inflammatory cytokines could be used in clinical practice for more individual characterization of the inflammation.

STUDY DESIGN

Case-control study.

SETTING

Tertiary referral center.

PATIENTS

Convenience sample of 24 case patients with otitis media with effusion (OME) or chronic otitis media (COM), asthma, and CRSwNP, 14 of whom had NSAID intolerance, and 8 controls with OME but no history of asthma, CRSwNP, or NSAID intolerance.

INTERVENTION

Diagnostic.

MAIN OUTCOME AND MEASURE

Inflammatory cytokines including interleukins (IL)-4, IL-5, IL-6, IL-13, and interferon gamma (IFN-γ) in middle ear effusion.

RESULTS

The MEE mass fractions of IL-5 ( p = 0.003) and IFN-γ ( p = 0.048) were higher among our case patients with OME/COM than among the controls. For IL-4 and IL-13, the mass fractions were also higher among the case patients than the controls, but this difference was not statistically significant ( p = 0.199 and p = 0.617, respectively). We found no difference between the IL-6 mass fractions of the groups. We found notable heterogeneity in individual patients' cytokine levels.

CONCLUSIONS

According to our findings, OM, when present, should be considered part of the respiratory inflammatory process associated with asthma and CRSwNP. The individual differences in MEE cytokine levels could be useful as biomarkers.

Endotyping Chronic Respiratory Diseases: T2 Inflammation in the United Airways Model

Over the past 15 years, the paradigm of viewing the upper and lower airways as a unified system has progressively shifted the approach to chronic respiratory diseases (CRDs). As the global prevalence of CRDs continues to increase, it becomes evident that acknowledging the presence of airway pathology as an integrated entity could profoundly impact healthcare resource allocation and guide the implementation of pharmacological and rehabilitation strategies. In the era of precision medicine, endotyping has emerged as another novel approach to CRDs, whereby pathologies are categorized into distinct subtypes based on specific molecular mechanisms. This has contributed to the growing acknowledgment of a group of conditions that, in both the upper and lower airways, share a common type 2 (T2) inflammatory signature. These diverse pathologies, ranging from allergic rhinitis to severe asthma, frequently coexist and share diagnostic and prognostic biomarkers, as well as therapeutic strategies targeting common molecular pathways. Thus, T2 inflammation may serve as a unifying endotypic trait for the upper and lower airways, reinforcing the practical significance of the united airways model. This review aims to summarize the literature on the role of T2 inflammation in major CRDs, emphasizing the value of common biomarkers and integrated treatment strategies targeting shared molecular mechanisms.

[Importance of aspirin challenges in patients with NSAID-exacerbated respiratory disease]

BACKGROUND

Nonsteroidal anti-inflammatory drug-exacerbated respiratory disease (N-ERD) is often characterized by a severe course of chronic rhinosinusitis with nasal polyps (CRSwNP), comorbid asthma, and NSAID hypersensitivity. The gold standard for N-ERD diagnosis is challenge with acetylsalicylic acid (ASA). In expert recommendations, the diagnosis of N-ERD is established based on a plausible positive history of NSAID hypersensitivity and CRSwNP with asthma.

OBJECTIVE

The following review describes the performance of ASA challenges and their sensitivity and specificity. It also examines the extent to which a positive history of NSAID hypersensitivity correlates with ASA challenge results in clinical trials and when ASA challenges should be performed.

RESULTS AND CONCLUSION

ASA challenges have high sensitivity and specificity. In clinical ASA challenge studies, there is a high concordance between a positive history of NSAID hypersensitivity obtained by rhinologists and the measured data of ASA challenge in patients with CRSwNP and comorbid asthma. Therefore, ASA challenge is primarily indicated in patients with an unclear history of NSAID hypersensitivity.

CHI3L1 on fibrinolytic system imbalance in chronic rhinosinusitis with nasal polyp

Background

Chronic rhinosinusitis (CRS) is an inflammatory disease affecting more than 10% of the global adult population. It is classified into Th1, Th2, and Th17 endotypes and eosinophilic and non-eosinophilic types. Th2-based inflammation and eosinophilic CRS (ECRS) are associated with tissue remodeling and fibrinolytic system impairment.

Objective

To elucidate the role of eosinophils in inducing fibrin deposition in CRS nasal polyp tissues and explore potential regulatory mechanisms.

Methods

We analyzed the expression of genes related to the serpin family and fibrinolytic system using Gene Expression Omnibus and Next-generation sequencing data. Differentially expression genes (DEGs) analysis was used to compare control and nasal polyp tissues, followed by KEGG and Gene ontology (GO) analysis. We measured the expression and correlation of plasminogen activator-1 (PAI-1), tissue plasminogen activator (t-PA), urokinase plasminogen activator (u-PA), and urokinase plasminogen activator surface receptor (u-PAR) in CRS tissues, and evaluated the effect of eosinophils on the fibrinolytic system using a cytokine array and co-culture.

Results

Nasal polyp tissues showed upregulated PAI-1, u-PA, and u-PAR expression and downregulated t-PA expression. Fibrinolytic system-related genes positively correlated with Th2 cytokines, except for t-PA. Eosinophil-derived Chitinase-3-like protein 1 (CHI3L1) increased PAI-1 expression and decreased t-PA levels in fibroblasts and epithelial cells. The inhibition of CHI3L1 suppresses these alterations.

Conclusion

CHI3L1 contributes to fibrin deposition by impairing the fibrinolytic system during nasal polyp formation. The regulation of CHI3L1 expression may inhibit fibrin deposition and edema in ECRS, presenting a potential treatment for this condition.

Antibody-based therapeutics for chronic rhinosinusitis with nasal polyps

INTRODUCTION

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a prevalent inflammatory condition with heterogenous underlying endotypes, the most common being type 2 mediated inflammation. Several biologics have been developed to target specific pro-inflammatory cytokines and their receptors with proven efficacy in both quantitative and qualitative outcomes in patients with severe uncontrolled disease. However, there is an ongoing debate on the role of biologics relative to conventional therapies for CRSwNP and their efficacy in patient subgroups with non-polyp type 2 disease.

AREAS COVERED

This review examines the evidence on the efficacy and safety of biologics in CRSwNP, recommendations for their use, and discusses the broader economic factors influencing their application in clinical practice.

EXPERT OPINION

Emerging real-life data demonstrating the variable efficacy of the available biologics for patients with CRSwNP, coupled with the high cost compared to conventional therapies such as surgery, renders biologics to be considered as an add-on therapy in the majority of cases. However, ongoing research into increasing biologic dose intervals and novel therapies targeting alternative pathways may offer a more cost-effective and sustainable option in future.

IL-10 inhibition during immunization improves vaccine-induced protection against Staphylococcus aureus infection

Staphylococcus aureus is a major human pathogen. An effective anti-S. aureus vaccine remains elusive as the correlates of protection are ill-defined. Targeting specific T cell populations is an important strategy for improving anti-S. aureus vaccine efficacy. Potential bottlenecks that remain are S. aureus-induced immunosuppression and the impact this might have on vaccine-induced immunity. S. aureus induces IL-10, which impedes effector T cell responses, facilitating persistence during both colonization and infection. Thus, it was hypothesized that transient targeting of IL-10 might represent an innovative way to improve vaccine efficacy. In this study, IL-10 expression was elevated in the nares of persistent carriers of S. aureus, and this was associated with reduced systemic S. aureus-specific Th1 responses. This suggests that systemic responses are remodeled because of commensal exposure to S. aureus, which negatively implicates vaccine function. To provide proof of concept that targeting immunosuppressive responses during immunization may be a useful approach to improve vaccine efficacy, we immunized mice with T cell-activating vaccines in combination with IL-10-neutralizing antibodies. Blocking IL-10 during vaccination enhanced effector T cell responses and improved bacterial clearance during subsequent systemic and subcutaneous infection. Taken together, these results reveal a potentially novel strategy for improving anti-S. aureus vaccine efficacy.

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.

Impact of Dupilumab on Sinonasal Symptoms and Outcomes in Severe Chronic Rhinosinusitis With Nasal Polyps

OBJECTIVES

To assess the severity of the top 5 22-item Sino-Nasal Outcome Test (SNOT-22) items ranked most important by patients with chronic rhinosinusitis with nasal polyps (CRSwNP), the effect of dupilumab on these items, and their association with objective disease measures.

STUDY DESIGN

Post hoc analysis of the SINUS-24 (NCT02912468) and SINUS-52 (NCT02898454) clinical trials.

SETTING

Multinational, multicenter, randomized, double-blind, placebo-controlled, parallel-group studies.

METHODS

Patients ranked the SNOT-22 items most affecting their health at baseline. Item symptom severity (0-5 scale) was assessed at baseline, Week 24 (W24), and Week 52 (W52). Changes in nasal polyps score (NPS) and Lund-Mackay (LMK) scores were assessed in patients with/without SNOT-22 items improvements of at least 1 severity group point at W24 and W52.

RESULTS

The SNOT-22 items ranked most important at baseline were "decreased sense of smell/taste" (87% of patients), followed by "nasal blockage" (82%), "postnasal discharge" (40%), "thick nasal discharge" (37%), and "wake up at night" (26%); 82%, 61%, 32%, 40%, and 26% of patients reported severe symptoms (score 4 or 5) for these items, respectively. Dupilumab improved score severity for all top 5 items versus placebo at W24 and W52. Improvements in NPS and LMK scores were numerically greater in patients with improvements in the SNOT-22 top 5 items.

CONCLUSION

Loss of smell/taste was ranked as the most important symptom by patients with CRSwNP. Dupilumab reduced the severity of the top 5 most important SNOT-22 items versus placebo, in parallel with improvements in objective disease measures.

CLINICAL TRIAL REGISTRATION

SINUS-24 and SINUS-52 clinical trials were registered with ClinicalTrials.gov, identifiers NCT02912468 and NCT02898454, respectively.

Multidimensional Impact of Dupilumab on Chronic Rhinosinusitis with Nasal Polyps: A Complete Health Technology Assessment of Clinical, Economic, and Non-Clinical Domains

Chronic RhinoSinusitis with Nasal Polyps (CRSwNP) represents a condition mainly caused by the type 2 inflammation presence and marked by the existence of polyps within the nasal and paranasal sinuses. The standard of care includes intranasal steroids, additional burst of systemic steroids, if needed, and surgery. However, recurrence is common, especially among patients with comorbid type 2 inflammatory diseases. Recently, biological drugs, addressing the underlying cause of the disease, have been approved in Italy (dupilumab, omalizumab, and mepolizumab). A Health Technology Assessment was conducted to define multidimensional impact, assuming Italian NHS perspective and a 12-month time horizon. The EUnetHTA Core Model was deployed, using the following methods to analyze the domains: (i) literature evidence; (ii) administration of semi-structured questionnaires to 17 healthcare professionals; (iii) health economics tools to define the economic sustainability for the system. Evidence from NMA and ITC showed a more favorable safety profile and better efficacy for dupilumab compared with alternative biologics. All the analyses, synthesizing cost and efficacy measures, showed that dupilumab is the preferable alternative. Specifically, the cost per responder analysis for dupilumab, exhibiting a 67.0% response rate at Week 52, is notably economical at 14,209EUR per responder. This presents a more economical profile compared with the cost per responder for omalizumab (36.2% response rate) at 24,999EUR and mepolizumab (28.5% response rate) at 31,863EUR. These results underscore dupilumab's potential, not merely in terms of clinical outcomes, but also in terms of economic rationality, thereby solidifying its status as a valid and preferrable alternative in the management of CRSwNP, in the context of the Italian NHS.

Non-Type 2 and Mixed Inflammation in Chronic Rhinosinusitis and Lower Airway Disease

OBJECTIVE

The aim was to discuss the role of non-type 2 inflammation in patients diagnosed with chronic rhinosinusitis (CRS) and comorbid lower airway disease.

DATA SOURCES

Medline, Embase, National Institute for Health and Care Excellence, TRIP Database, ProQuest, Clinicaltrials.gov, Cochrane Central Registry of Controlled Trials, Web of Science, government and health organizations, and graduate-level theses.

REVIEW METHODS

This scoping review followed PRISMA-ScR guidelines. Search strategy was peer-reviewed by medical librarians. Studies were included if they utilized airway sampling, non-type 2 cytokines, and patients with CRS and lower airway disease.

RESULTS

Twenty-seven from 7060 articles were included. In patients with CRS and comorbid asthma, aspirin-exacerbated respiratory disease (AERD), and chronic obstructive pulmonary disease (COPD)/bronchiectasis, 60% (n = 12), 33% (n = 2), and 100% (n = 1), respectively, demonstrated mixed or non-type 2 endotypes. Comorbid CRS and asthma produced type 1 (n = 1.5), type 2 (n = 8), type 3 (n = 1), mixed type 1/2 (n = 1), and mixed type 1/2/3 (n = 8.5) endotype shifts. AERD demonstrated type 2 (n = 4), mixed type 2/3 (n = 1), and mixed type 1/2/3 (n = 1) endotype shifts. CRS with COPD or bronchiectasis demonstrated a mixed 1/2 (n = 1) endotype shift.

CONCLUSION

Type 2 disease has been extensively reviewed due to advent biologics targeting type 2 inflammation, but outcomes may be suboptimal due to the presence of non-type 2 inflammation. A proportion of patients with CRS and comorbid lower airway disease demonstrated mixed and non-type 2 endotype shifts. This emphasizes that patients with unified airway disease may have forms of inflammation beyond classical type 2 disease which could inform biologic development. Laryngoscope, 134:1005-1013, 2024.

Biomarkers of immediate drug hypersensitivity

Immediate drug hypersensitivity reactions (IDHRs) are a burden for patients and the health systems. This problem increases when taking into account that only a small proportion of patients initially labelled as allergic are finally confirmed after an allergological workup. The diverse nature of drugs involved will imply different interactions with the immunological system. Therefore, IDHRs can be produced by a wide array of mechanisms mediated by the drug interaction with specific antibodies or directly on effector target cells. These heterogeneous mechanisms imply an enhanced complexity for an accurate diagnosis and the identification of the phenotype and endotype at early stages of the reaction is of vital importance. Currently, several endophenotypic categories (type I IgE/non-IgE, cytokine release, Mast-related G-protein coupled receptor X2 (MRGPRX2) or Cyclooxygenase-1 (COX-1) inhibition and their associated biomarkers have been proposed. A precise knowledge of endotypes will permit to discriminate patients within the same phenotype, which is crucial in order to personalise diagnosis, future treatment and prevention to improve the patient's quality of life.

Immune endotyping and gene expression profile of patients with chronic rhinosinusitis with nasal polyps in the aspirin-exacerbated respiratory disease (AERD) and the non-AERD subgroups

BACKGROUND

Chronic Rhinosinusitis (CRS) is a paranasal sinus inflammatory disease and is divided into two subgroups defined as CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). CRSwNP displays a T helper (Th)2 biased phenotype, and based on sensitivity or tolerance to aspirin or non-steroidal anti-inflammatory drugs (NSAID), is further subdivided into Aspirin-exacerbated respiratory disease (AERD) and non-AERD groups. Considering the challenge of diagnosis and treatment in patients with CRSwNP, particularly the AERD subtype, and the significance of endotyping in these patients, we examined the immune profile and endotyping based on gene expression analysis in the AERD and the non-AERD groups of patients with CRSwNP.

MATERIAL AND METHOD

In this study, 21 patients were enrolled and were categorized into AERD (N = 10) and non-AERD (N = 11) groups based on their sensitivity to aspirin. After the special washing period, nasal polyps were biopsied in both groups, and the infiltration of eosinophils, neutrophils, plasma cells, and lymphocytes was compared between the AERD and the non-AERD groups. Also, gene expression levels of transcription factors including Tbet, GATA3, RoRγt, and FoxP3 and inflammatory cytokines including interleukin (IL)1β, IL1RAP (IL1 receptor accessory protein), IL2, IL4, IL5, IL10, IL13, IL17, TNFα, and IFNγ were investigated by quantitative Real-time PCR (qRT-PCR). Statistical analyses were performed using analytical tests including Kolmogorov-Smirnov, Mann-Whitney, and T-test. A P value less than 0.05 was considered statistically significant.

RESULTS

The mean ± SD age of the studied groups was 37 ± 8.7 years old (21-50) for the AERD, and 40.4 ± 7.7 years old (31-52) for the non-AERD. LMS/EPOS/SNOT scores and pulmonary function tests showed no difference between the two groups. Serum immunoglobulin E (IgE) levels were found to be higher in patients with AERD (p = 0.04), however, the peripheral blood counts of eosinophils were comparable in the two groups. In the histopathologic analysis, the AERD group showed higher percentages of eosinophils (p = 0.04), neutrophils (p = 0.04), and plasma cells (p = 0.04) than the non-AERD group. Additionally, the gene expression levels of GATA3 (p = 0.001), IL4 (p = 0.04), IL5 (p = 0.007), and IL17 (p = 0.03) were significantly higher in the AERD than the non-AERD groups.

CONCLUSION

Higher gene expression levels of GATA3, IL4, IL5, and IL17 were observed in the AERD group compared with the non-AERD group. These findings point to distinct patterns of inflammation in patients with AERD, with a predominance of Th2 inflammation.

[Features of inflammatory endotypes and phenotypes in chronic rhinosinusitis]

Recently, significant progress has been made in identifying the cellular and molecular mechanisms responsible for the pathogenesis of chronic rhinosinusitis (CRS). Cohort studies of CRS have led to advances in the clinical understanding of this disease. New therapeutic agents have been approved or are undergoing clinical trials to expand treatment options for this disease. One of the promising areas in medicine is the provision of personalized clinical care. From this perspective, CRS can be divided into three different endotypes depending on the type of underlying inflammatory response. In the United States, CRS with and without nasal polyps is predominantly characterized as the second inflammatory endotype. CRS with nasal polyps (about 17%) and without nasal polyps (up to 20%) belongs to the 1st and 3rd inflammatory endotypes, respectively. And if for the second inflammatory endotype the effectiveness of targeted biological therapy is beyond doubt, then for the first and third inflammatory endotypes the principles of such conservative therapy are under active development. Moreover, large validated studies to confirm associations between CRS phenotypes and endotypes, as well as to find effective biological markers of inflammatory endotypes, remain to be performed.

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.

Inflammatory characteristics of central compartment atopic disease

BACKGROUND

Central compartment atopic disease (CCAD) is an emerging phenotype of chronic rhinosinusitis with nasal polyposis (CRSwNP) characterized by prominent central nasal inflammatory changes. This study compares the inflammatory characteristics of CCAD relative to other phenotypes of CRSwNP.

METHODS

A cross-sectional analysis of data from a prospective clinical study was performed on patients with CRSwNP who were undergoing endoscopic sinus surgery (ESS). Patients with CCAD, aspirin-exacerbated respiratory disease (AERD), allergic fungal rhinosinusitis (AFRS), and non-typed CRSwNP (CRSwNP NOS) were included and mucus cytokine levels and demographic data were analyzed for each group. Chi-squared/Mann-Whitney U tests and partial least squares discriminant analysis (PLS-DA) were performed for comparison and classification.

RESULTS

A total of 253 patients were analyzed (CRSwNP, n = 137; AFRS, n = 50; AERD, n = 42; CCAD, n = 24). Patients with CCAD were the least likely to have comorbid asthma (p = 0.0004). The incidence of allergic rhinitis in CCAD patients did not vary significantly compared to patients with AFRS and AERD, but was higher compared to patients with CRSwNP NOS (p = 0.04). On univariate analysis, CCAD was characterized by less inflammatory burden, with reduced levels of interleukin 6 (IL-6), IL-8, interferon gamma (IFN-γ), and eotaxin relative to other groups and significantly lower type 2 cytokines (IL-5, IL-13) relative to both AERD and AFRS. These findings were supported by multivariate PLS-DA, which clustered CCAD patients into a relatively homogenous low-inflammatory cytokine profile.

CONCLUSIONS

CCAD has unique endotypic features compared to other patients with CRSwNP. The lower inflammatory burden may be reflective of a less severe variant of CRSwNP.

Effect of Dupilumab on Type 2 Biomarkers in Chronic Rhinosinusitis With Nasal Polyps: SINUS-52 Study Results

OBJECTIVES

Chronic rhinosinusitis with nasal polyps (CRSwNP), asthma, and non-steroidal anti-inflammatory drug-exacerbated respiratory disease (NSAID-ERD) are frequent coexisting conditions and share type 2 inflammatory pathophysiology, with interleukin (IL)-4 and IL-13 as key cytokines. Dupilumab is a monoclonal antibody that blocks the shared receptor for IL-4 and IL-13. The objective of this analysis was to evaluate dupilumab's effect on type 2 inflammation biomarkers in patients with CRSwNP with/without coexisting asthma or NSAID-ERD from the SINUS-52 (NCT02898454) study.

METHODS

Patients received treatment with dupilumab or placebo for 52 weeks. Blood and urinary biomarkers were evaluated through 52 weeks, and nasal secretions and mucosa brushings through 24 weeks.

RESULTS

Of 447 patients, 60% had coexisting asthma and 27% had coexisting NSAID-ERD. At baseline, blood eotaxin-3, eosinophils, and periostin, nasal secretion eotaxin-3, and urinary leukotriene E4 were significantly higher in patients with coexisting NSAID-ERD than without. Dupilumab reduced eotaxin-3, thymus and activation-regulated chemokine, periostin, and total immunoglobulin E in blood, eotaxin-3, periostin, IL-5, and eosinophil cationic protein in nasal secretions, and leukotriene E4 in urine. Reductions were generally similar or greater in the subgroups with asthma and NSAID-ERD than without. Dupilumab also reduced MUC5AC and mast cell counts in nasal mucosa brushings.

CONCLUSION

Dupilumab reduced local and systemic type 2 inflammatory biomarkers in patients with CRSwNP, including mast cells in nasal mucosa and cysteinyl leukotrienes in urine. These findings provide insight into the processes driving CRSwNP and the mechanisms of dupilumab's therapeutic effects.

CLINICAL TRIAL REGISTRY NAME

SINUS-52 https://www.clinicaltrials.gov/ct2/show/NCT02898454.

CLINICALTRIALS.GOV IDENTIFIER

NCT02898454.

Systematic Review of Protein Biomarkers in Adult Patients With Chronic Rhinosinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) is a heterogeneous condition characterized by differing inflammatory endotypes. The identification of suitable biomarkers could enable personalized approaches to treatment selection.

OBJECTIVE

This study aimed to identify and summarize clinical studies of biomarkers in adults with CRS in order to inform future research into CRS endotypes.

METHODS

We conducted systematic searches of MEDLINE and Web of Science from inception to January 30, 2022 and included all clinical studies of adult CRS patients and healthy controls measuring biomarkers using enzyme-linked immunosorbent assays or Luminex immunoassays. Outcomes included the name and tissue type of identified biomarkers and expression patterns within CRS phenotypes. Study quality was assessed using the National Institutes of Health quality assessment tool for observational cohort and cross-sectional studies. A narrative synthesis was performed.

RESULTS

We identified 78 relevant studies involving up to 9394 patients, predominantly with CRS with nasal polyposis. Studies identified 80 biomarkers from nasal tissue, 25 from nasal secretions, 14 from nasal lavage fluid, 24 from serum, and one from urine. The majority of biomarkers found to distinguish CRS phenotypes were identified in nasal tissue, especially in nasal polyps. Serum biomarkers were more commonly found to differentiate CRS from controls. The most frequently measured biomarker was IL-5, followed by IL-13 and IL-4. Serum IgE, IL-17, pentraxin-3 and nasal phospho-janus kinase 2, IL-5, IL-6, IL-17A, granulocyte-colony stimulating factor, and interferon gamma were identified as correlated with disease severity.

CONCLUSION

We have identified numerous potential biomarkers to differentiate a range of CRS phenotypes. Future studies should focus on the prognostic role of nasal tissue biomarkers or expand on the more limited studies of nasal secretions and nasal lavage fluid.We registered this study in PROSPERO (CRD42022302787).

Differences in Clinical and Immunological Characteristics According to the Various Criteria for Tissue Eosinophilia in Chronic Rhinosinusitis With Nasal Polyps

OBJECTIVES

Several criteria exist for classifying chronic rhinosinusitis with nasal polyps (CRSwNP) as eosinophilic or non-eosinophilic. This study attempted to evaluate several criteria for defining eosinophilic CRSwNP from clinical and immunological perspectives.

METHODS

A cohort of 84 patients (73 patients with CRSwNP and 11 control patients) was retrospectively analyzed. Patients were divided into eosinophilic and non-eosinophilic CRSwNP based on four different criteria: eosinophils (EOS) accounting for more than 20% of the total inflammatory cells; ≥70 EOS per high-power field (HPF); >55 EOS/HPF; and ≥10 EOS/HPF. Preoperative clinical characteristics, the immunological profiles of 14 cytokines from nasal tissue, and postoperative outcomes were compared between eosinophilic and non-eosinophilic CRSwNP based on each criterion. These criteria were immunologically validated by using 14 cytokines to predict the performance of tissue eosinophilia with a random forest model.

RESULTS

Patients with eosinophilic CRSwNP were significantly older when the criterion of ≥10 EOS/HPF or EOS >20% was used. The number of patients with aspirin intolerance was significantly higher in eosinophilic CRSwNP based on the criterion of EOS >20%. From an immunological perspective, non-type 2 inflammatory cytokines were significantly higher in non-eosinophilic CRSwNP with the criterion of EOS >20% of the total inflammatory cells. In addition, the criterion of EOS >20% of the total inflammatory cells resulted in the best prediction of eosinophilic CRSwNP, with an accuracy of 88.10% and area under the curve of 0.94.

CONCLUSION

Clinical and immunological characteristics were different between eosinophilic and non-eosinophilic CRSwNP depending on a variety of criteria, and the.

RESULTS

of this study should be taken into account when choosing the criterion for defining eosinophilic CRSwNP and interpreting the data accordingly.

Dupilumab-induced eosinophilia in patients with diffuse type 2 chronic rhinosinusitis

BACKGROUND

Dupilumab, a monoclonal anti-IL-4Rα antibody, is approved for several type 2 mediated inflammatory diseases like asthma, atopic dermatitis, and diffuse type 2 chronic rhinosinusitis (CRS). Clinical studies had reported a transient increase in blood eosinophils during dupilumab therapy. This study aimed to assess the impact of elevated blood eosinophils on clinical outcome and to investigate the cause of high blood eosinophil levels under dupilumab therapy.

METHODS

Patients suffering from diffuse type 2 CRS treated with dupilumab were examined on days 0, 28, 90, and 180 after therapy start. Sino-Nasal-Outcome-Test Score (SNOT-22), Total Nasal Polyp Score (TNPS), and blood samples were collected. Cytokine measurements and proteomics analysis were conducted. Flow cytometry analysis measured receptor expression on eosinophils.

RESULTS

Sixty-eighty patients were included. Baseline eosinophilia ≥0.3G/L was observed in 63.2% of patients, and in 30.9% of patients, eosinophils increased by ≥0.5G/L under dupilumab. Subjects with eosinophilia ≥0.3G/L at baseline had the best SNOT-22 mean change compared to no eosinophilia. Eosinophil elevation during dupilumab therapy had no impact on clinical scores. The eosinophil adhesion molecule VCAM-1 decreased significantly during therapy in all patients. The chemokine receptor CXCR4 was significantly down- and IL-4 upregulated in subjects with eosinophil increase.

CONCLUSION

Our findings suggest that increased eosinophils in type 2 CRS are associated with a good clinical response to dupilumab. Patients with elevated IL-4 at baseline developed dupilumab-induced transient eosinophilia. We identified the downregulation of VCAM-1 and surface markers CD49d and CXCR4 on eosinophils as possible explanations of dupilumab-induced eosinophilia.

Chronic rhinosinusitis is not associated with increased incidence of acute myocardial infarction: A national population-based study

BACKGROUND & AIMS

Chronic rhinosinusitis (CRS) is one of the most prevalent upper respiratory tract diseases. However, little is known the effect of CRS on the cardiovascular aspects of patients. This study aimed to investigate the incidence of acute myocardial infarction (AMI) in patients with CRS compared with that in the general population.

METHODS

This retrospective cohort study was performed using the Korean National Health Insurance Service (NHIS) database. To minimize confounding, age, sex, and cardiovascular risk profiles were adjusted. The primary endpoint was newly diagnosed AMI in patients between January 2005 and December 2018. The relative risk of AMI in patients with CRS was compared with that in controls. Kaplan-Meier survival curves and Cox proportional regression tests were used for statistical analyses.

RESULTS

Among 5,179,981 patients from the NHIS database, 996,679 patients with CRS were selected. The control group was 10 times (n = 9,966,790) the number of individuals in the CRS group. The CRS group had better cardiovascular profiles than those of the control group and had an adjusted hazard ratio of 0.99 (95% confidence interval, 0.97-1.02) for AMI.

CONCLUSION

There was no significant association between the two groups regardless of the presence of nasal polyps. This is the first study adjusting cardiovascular risk profiles and analyzing the relationship between CRS and AMI. CRS was not associated with a high incidence of AMI after adjusting for cardiovascular risk factors.

A Decade of Pathogenesis Advances in Non-Type 2 Inflammatory Endotypes in Chronic Rhinosinusitis: 2012-2022

Chronic rhinosinusitis (CRS) is a heterogeneous disease characterized by localized inflammation of the upper airways. CRS includes two main phenotypes, namely, CRS with nasal polyps and CRS without nasal polyps. The phenotype-based classification method cannot reflect the pathological mechanism. The endotype-based classification method has been paid more and more attention by researchers. It is mainly divided into type 2 and non-type 2 endotypes. The mechanism driving the pathogenesis of non-type 2 inflammation is currently unknown. In this review, the PubMed and Web of Science databases were searched to conduct a critical analysis of representative literature works on the pathogenesis of non-type 2 inflammation in CRS published in the past decade. This review summarizes the latest evidence that may lead to the pathogenesis of non-type 2 inflammation. It is the main method that analyzing the pathogenesis from the perspective of immunology. Genomics and proteomics technique provide new approaches to the study of the pathogenesis. Due to differences in race, environment, geography, and living habits, there are differences in the occurrence of non-type 2 inflammation, which increase the difficulty of understanding the pathogenesis of non-type 2 inflammation in CRS. Studies have confirmed that non-type 2 endotype is more common in Asian patients. The emergence of overlap and unclassified endotypes has promoted the study of heterogeneity in CRS. In addition, as the source of inflammatory cells and the initiation site of the inflammatory response, microvessels and microlymphatic vessels in the nasal mucosal subepithelial tissue participate in the inflammatory response and tissue remodeling. It is uncertain whether CRS patients affect the risk of infection with SARS-CoV-2. In addition, the pathophysiological mechanism of non-type 2 CRS combined with COVID-19 remains to be further studied, and it is worth considering how to select the befitting biologics for CRS patients with non-type 2 inflammation.

Eosinophil Cationic Protein Variation in Patients with Asthma and CRSwNP Treated with Dupilumab

BACKGROUND

Asthma is a clinical syndrome characterized by recurrent episodes of airway obstruction, bronchial hyperresponsiveness and airway inflammation. Most patients with asthma present a "type 2" (TH2) inflammation. ILC2 and TH2 cells release cytokines IL4, IL-13 and IL-5. CRSwNP is a condition characterized by hyposmia or anosmia, nasal congestion, nasal discharge, and face pain or pressure that last for at least 12 weeks in a row without relief. Both asthma and CRSwNP are often characterized by a type 2 inflammation endotype and are often present in the same patient. Dupilumab is a fully human monoclonal antibody targeting the interleukin-4 receptor α (IL-4Rα) subunit, blocking IL4/IL-4Rα binding and IL13. It has been labelled for the treatment of moderate to severe asthma in patients from the age of 12 years with an eosinophilic phenotype, and it has demonstrated efficacy and acceptable safety. Our study aims to investigate the effects of dupilumab on type 2 inflammatory biomarkers, such as eosinophils and eosinophil cationic protein (ECP). ECP is an eosinophil-derived substance contained in granules that are released during inflammation and causes various biological effects, including tissue damage in asthmatic airways.

METHODS

ECP, Eosinophil counts (EOS), and total immunoglobulin E (IgE) levels were longitudinally measured using immunoassays in the serum of 21 patients affected by CRSwNP, of which 17 had asthma as a comorbidity, receiving 300 mg dupilumab every two weeks.

RESULTS

The EOS and ECP, after a first phase of significant increase due to the intrinsic characteristic of the block of IL-4 and IL-13, returned to the baseline 10 months after the initial administration of dupilumab. Fractional exhaled nitric oxide (FeNO) and serum total IgE decreased significantly after 9 months. Asthma Control Test (ACT) scores improved after dupilumab treatment. FEV1% and FEV1 absolute registered a significant improvement at 10 months.

CONCLUSIONS

Patients who received 300 milligrams of dupilumab every two weeks first experienced a temporary increase in eosinophils (EOS) and eosinophil cationic protein (ECP), then exhibited a gradual decline in these variables with a subsequent return to the initial baseline levels. When compared to the baseline, we observed that the levels of IgE and FeNO decreased over time, while there was an increase in both FEV1 and FEV1%.

Staphylococcus aureus biofilm properties and chronic rhinosinusitis severity scores correlate positively with total CD4+ T-cell frequencies and inversely with its Th1, Th17 and regulatory cell frequencies

Chronic rhinosinusitis (CRS) represents chronic inflammation of the sinus mucosa characterised by dysfunction of the sinuses' natural defence mechanisms and induction of different inflammatory pathways ranging from a Th1 to a Th2 predominant polarisation. Recalcitrant CRS is associated with Staphylococcus aureus dominant mucosal biofilms; however, S. aureus colonisation of the sinonasal mucosa has also been observed in healthy individuals challenging the significance of S. aureus in CRS pathogenesis. We aimed to investigate the relationship between CRS key inflammatory markers, S. aureus biofilm properties/virulence genes and the severity of the disease. Tissue samples were collected during endoscopic sinus surgery from the ethmoid sinuses of CRS patients with (CRSwNP) and without (CRSsNP) nasal polyps and controls (n = 59). CD3+ T-cell subset frequencies and key inflammatory markers of CD4+ helper T cells were determined using FACS analysis. Sinonasal S. aureus clinical isolates were isolated (n = 26), sequenced and grown into biofilm in vitro, followed by determining their properties, including metabolic activity, biomass, colony-forming units and exoprotein production. Disease severity was assessed using Lund-Mackay radiologic scores, Lund-Kennedy endoscopic scores and SNOT22 quality of life scores. Our results showed that S. aureus biofilm properties and CRS severity scores correlated positively with total CD4+ T-cell frequencies but looking into CD4+ T-cell subsets showed an inverse correlation with Th1 and Th17 cell frequencies. CD4+ T-cell frequencies were higher in patients harbouring lukF.PV-positive S. aureus while its regulatory and Th17 cell subset frequencies were lower in patients carrying sea- and sarT/U-positive S. aureus. Recalcitrant CRS is characterised by increased S. aureus biofilm properties in relation to increased total CD4+ helper T-cell frequencies and reduced frequencies of its Th1, Th17 and regulatory T-cell subsets. These findings offer insights into the pathophysiology of CRS and could lead to the development of more targeted therapies.

Long-term clinical outcomes of aspirin-exacerbated respiratory disease: Real-world data from an adult asthma cohort

BACKGROUND

Aspirin-exacerbated respiratory disease (AERD) is a phenotype of severe asthma, but its disease course has not been well documented compared with that of aspirin-tolerant asthma (ATA).

OBJECTIVES

This study aimed to investigate the long-term clinical outcomes between AERD and ATA.

METHODS

AERD patients were identified by the diagnostic code and positive bronchoprovocation test in a real-world database. Longitudinal changes in lung function, blood eosinophil/neutrophil counts, and annual numbers of severe asthma exacerbations (AEx) were compared between the AERD and the ATA groups. Within a year after baseline, two or more severe AEx events indicated severe AERD, whereas less than two AEx events indicated nonsevere AERD.

RESULTS

Among asthmatics, 353 had AERD in which 166 and 187 patients had severe and nonsevere AERD, respectively, and 717 had ATA. AERD patients had significantly lower FEV1%, higher blood neutrophil counts, and higher sputum eosinophils (%) (all p < .05) as well as higher levels of urinary LTE4 and serum periostin, and lower levels of serum myeloperoxidase and surfactant protein D (all p < .01) than those with ATA. In a 10-year follow-up, the severe AERD group maintained lower FEV1% with more severe AEs than the nonsevere AERD group.

CONCLUSION AND CLINICAL RELEVANCE

We demonstrated that AERD patients presented poorer long-term clinical outcomes than ATA patients in real-world data analyses.

Comorbid asthma in patients with chronic rhinosinusitis with nasal polyps: did dupilumab make a difference?

BACKGROUND

The clinical heterogeneity of chronic rhinosinusitis (CRS) and bronchial asthma is attributable to different underlying inflammatory profiles. However, the similarity between CRS with nasal polyps (CRSwNP) and type-2 asthma pathophysiology speculates that one biological therapy could affect both comorbidities. Despite dupilumab, a monoclonal antibody that targets IL-4α and IL-13 receptors, being used in patients with nasal polyps and severe asthma, real-life data about its efficacy in improving the quality of life and patient symptoms is still lacking. This study's primary objective was to evaluate dupilumab treatment's effect on the frequency of olfactory symptoms and health-related quality of life tests as measured by the Sino-nasal outcome test (SNOT-22) in patients with NP. The secondary objective was the effect of dupilumab on asthma symptom control as measured by the asthma control test (ACT).

METHODS

A prospective study was conducted of 166 patients with CRSwNP, with or without asthma. The following variables were collected at baseline and after at least six months of continuous dupilumab therapy; SNOT-22, olfactory symptoms frequency, and ACT score.

RESULTS

Asthma prevalence in patients with CRSwNP was high (59.63%), and being female with a history of frequent use of oral corticosteroid (OCS) courses and repeated unsuccessful nasal and para-nasal surgeries for polyposis increased the likelihood of having underlying asthma by 2, 1 and 4 times more, respectively. Additionally, being asthmatic required a longer duration of dupilumab treatment. However, both the health-related quality of life and olfactory symptoms improved equally in both groups.

CONCLUSION

Even with associated comorbid asthma in patients with CRSwNP, treatment with dupilumab could improve the quality of life, olfactory symptoms, and asthma symptom control.

Blood Basophils Relevance in Chronic Rhinosinusitis with Aspirin-Exacerbated Respiratory Disease

Aspirin-exacerbated respiratory disease (AERD) is characterized by eosinophilic asthma, chronic rhinosinusitis with nasal polyps (CRSwNP) and intolerance to cyclooxygenase-1 inhibitors. Interest is emerging in studying the role of circulating inflammatory cells in CRSwNP pathogenesis and its course, as well as their potential use for a patient-tailored approach. By releasing IL-4, basophils play a crucial role in activating the Th2-mediated response. The main aim of this study was to, first, investigate the level of the pre-operative blood basophils' values, blood basophil/lymphocyte ratio (bBLR) and blood eosinophil-to-basophil ratio (bEBR) as predictors of recurrent polyps after endoscopic sinus surgery (ESS) in AERD patients. The secondary aim was to compare the blood basophil-related variables of the AERD series (study group) with those of a control group of 95 consecutive cases of histologically non-eosinophilic CRSwNP. The AERD group showed a higher recurrence rate than the control group (p < 0.0001). The pre-operative blood basophil count and pre-operative bEBR were higher in AERD patients than in the control group (p = 0.0364 and p = 0.0006, respectively). The results of this study support the hypothesis that polyps removal may contribute to reducing the inflammation and activation of basophils.

Comparison of the clinical outcomes of patients with NSAID-exacerbated respiratory disease receiving aspirin or biologicals

OBJECTIVE

NSAID-exacerbated respiratory disease (NERD) is characterized by exacerbation of respiratory symptoms after NSAID intake. While research for specific treatment options continues in patients who cannot tolerate or are unresponsive to aspirin treatment after aspirin desensitization (ATAD), biologicals have emerged as a new therapeutic option in NERD patients. The aim of this study was to compare the quality of life, and the sinonasal and respiratory outcomes of NERD patients treated with ATAD or biologicals.

METHODS

Patients who have been followed up at a tertiary care allergy center and who have been receiving at least one of ATAD, mepolizumab or omalizumab for at least six months were included. Evaluations were made using sinonasal outcome test (SNOT-22), asthma control test (ACT), short form-36 (SF-36), blood eosinophil counts, need for recurrent functional endoscopic sinus surgeries (FESS), and asthma or rhinitis exacerbations requiring oral corticosteroids (OCS).

RESULTS

A total of 59 patients comprised of 35 (59%) females and 24 (41%) males with a mean age of 46.1 (min-max, 20-70) years were included. The baseline blood eosinophil count was higher, and a significant decrease in blood eosinophil counts was observed in the mepolizumab group compared to ATAD group (p = 0.001, p < 0.001, respectively). At follow-up, the rate of recurrent FESS was lower in the group that received mepolizumab (p = 0.02).

CONCLUSIONS

In NERD patients, mepolizumab significantly decreased blood eosinophil counts and recurrent FESS. There was no significant difference between the patients receiving ATAD or mepolizumab regarding other clinical parameters.

Endotyping Chronic Rhinosinusitis with Nasal Polyps: Understanding Inflammation Beyond Phenotypes

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a heterogenous group of inflammatory conditions impacting the nose and paranasal sinuses. Our understanding of the underlying pathobiology of CRSwNP has substantially improved due to ongoing translational research efforts. Advances in treatment options, including targeted respiratory biologic therapy for CRSwNP, allow for more personalized approaches for CRSwNP patient care. Patients with CRSwNP are typically classified to one or more endotype based on the presence of type 1, type 2, and type 3 inflammation. This review will discuss recent advances in our understanding of CRSwNP and how this may impact current and future treatment approaches for patients with CRSwNP.

New Developments in Allergic Fungal Rhinosinusitis Pathophysiology and Treatment

BACKGROUND

Allergic fungal rhinosinusitis (AFRS) is an endotype of chronic rhinosinusitis (CRS) with nasal polyps characterized by eosinophilic mucin laden with fungal hyphae entrapped in expanded sinus cavities with an exaggerated hypersensitivity to fungal elements. The last decade has elucidated fungi-driven inflammatory pathways contributing to the pathophysiology of chronic inflammatory respiratory diseases. In addition, novel therapeutic biologic options have become available for CRS over the last several years.

OBJECTIVE

To review the current literature examining AFRS, focusing on recent developments in our understanding of its pathophysiology and implications for treatment options.

METHODS

Review article.

RESULTS

Fungi-driven respiratory inflammation has been linked to fungal proteinases and toxin activity. In addition, AFRS patients demonstrate a local sinonasal immunodeficiency in antimicrobial peptides and hence limited antifungal activity, along with an exaggerated type 2 inflammatory response, highlighting a possible imbalanced type 1, type 2, and type 3 profile. The elucidation of these dysregulated molecular pathways has highlighted novel potential therapeutic targets. As such, the clinical management of AFRS, which once included surgery and extended courses of oral corticosteroids, is transitioning away from long courses of oral corticosteroids to incorporate novel delivery mechanisms of topical therapeutic targets and biologics for recalcitrant disease.

CONCLUSION

AFRS is an endotype of CRS with nasal polyps (CRSwNP) for which the molecular pathways leading to its inflammatory dysfunction are beginning to be illuminated. In addition to affecting treatment options, these understandings may shape necessary changes to diagnostic criteria and the extrapolated effects of environmental changes on AFRS. More critically, a better appreciation of fungi-driven inflammatory pathways may have implications for the understanding of broader CRS inflammation.