Expression of T helper cytokines associated with MUC5AC secretion in eosinophil-based endotypes of nasal polyps

Characteristics of mucin hypersecretion in different inflammatory patterns based on endotypes of chronic rhinosinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) is usually accompanied by mucin hypersecretion that can lead to mucus accumulation and impair nasal mucociliary clearance, thus exacerbating airway inflammation. Abnormal mucin hypersecretion is regulated by different T helper (Th) cytokines, which are associated with different endotype-driven inflammatory responses. Therefore, it is of great significance to understand how these factors regulate mucin hypersecretion to provide precise treatment strategies for different endotypes of CRS. BODY: Thus far, the most common endotypes of CRS are classified as type 1, type 2, or type 3 immune responses based on innate and adaptive cell-mediated effector immunity, and the representative Th cytokines in these immune responses, such as IFN-γ, TNF-α, IL-4, IL-5, IL-13, IL-10, IL-17, and IL-22, play an important regulatory role in mucin secretion. We reviewed all the related literature in the PubMed database to determine the expression of these Th cytokines in CRS and the role they play in the regulation of mucin secretion.

CONCLUSION

We believe that the main Th cytokines involved in specific endotypes of CRS play a key role in regulating abnormal mucin secretion, which contributes to better understanding of the pathogenesis of CRS and provides therapeutic targets for airway inflammatory diseases associated with mucin hypersecretion.

The role of hypoxia in the pathophysiology of chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a chronic inflammatory disease of the nasal cavity characterized by excessive nasal mucus secretion and nasal congestion. The development of CRS is related to pathological mechanisms induced by hypoxia. Under hypoxic conditions, the stable expression of both Hypoxia inducible factor-1 (HIF-1) α and HIF-2α are involved in the immune response and inflammatory pathways of CRS. The imbalance in the composition of nasal microbiota may affect the hypoxic state of CRS and perpetuate existing inflammation. Hypoxia affects the differentiation of nasal epithelial cells such as ciliated cells and goblet cells, induces fibroblast proliferation, and leads to epithelial-mesenchymal transition (EMT) and tissue remodeling. Hypoxia also affects the proliferation and differentiation of macrophages, eosinophils, basophils, and mast cells in sinonasal mucosa, and thus influences the inflammatory state of CRS by regulating T cells and B cells. Given the multifactorial nature in which HIF is linked to CRS, this study aims to elucidate the effect of hypoxia on the pathogenic mechanisms of CRS.

Revisiting Asian chronic rhinosinusitis in the era of type 2 biologics

Chronic rhinosinusitis (CRS) is a highly heterogeneous disorder exhibiting considerable epidemiological, clinical and immunopathological variations across patients with distinct ethnic backgrounds and in different geographic locations. Asian CRS patients present less eosinophilic and type 2 (T2) inflammation, but more prominent neutrophilic inflammation compared with patients in Western countries. Although several biologics targeting important elements of T2 inflammation, such as IL-4, IL-5, IL-13 and IgE, demonstrate promising benefit for Caucasian patients with recurrent nasal polyps, their efficacy in Asian patients remains poorly defined. The distinct endotypes in Asian patients warrant the identification and selection of patients who would benefit from T2 biologics in Asian countries. Additionally, developing novel treatments targeting neutrophilic, type 1, and type 3 inflammation may benefit approximately 50% of Asian CRS patients with non-T2 inflammation. In this review, we summarized and discussed recent progress in the study of Asian CRS endotypes in comparison with those in patients in Western countries, and the methods of identifying Asian patients with eosinophilic or T2 inflammation. T2 biologic treatment of Asian CRS patients, potential therapeutic candidates targeting non-T2 inflammation in Asian CRS patients and the progress on developing other T2 biologics were discussed.

Highlights in the advances of chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a complex upper airway inflammatory disease with a broad spectrum of clinical variants. As our understanding of the disease pathophysiology evolves, so too does our philosophy towards the approach and management of CRS. Endotyping is gaining favour over phenotype-based classifications, owing to its potential in prognosticating disease severity and delivering precision treatment. Endotyping is especially useful in challenging CRS with nasal polyposis cases, for whom novel treatment options such as biologicals are now available. The latest European Position Paper on Rhinosinusitis and Nasal Polyps (EPOS2020) reflects these changes with updated rhinosinusitis classifications and new integrated care pathways. With the coronavirus disease 2019 (COVID-19) pandemic, physicians and rhinologists have to balance the responsibility of managing their patients' upper airway while adequately protecting themselves from droplet and aerosol transmission. This review summarises the key updates from EPOS2020, endotype-based classification and biomarkers. The role of biologicals in CRS and the lessons we can draw from their use in severe asthma will be examined. Finally, the principles of CRS management during COVID-19 will also be discussed.

Efficacy and safety of treatment with biologicals for severe chronic rhinosinusitis with nasal polyps: A systematic review for the EAACI guidelines

This systematic review evaluates the efficacy and safety of biologicals for chronic rhinosinusitis with nasal polyps (CRSwNP) compared with the standard of care. PubMed, Embase, and Cochrane Library were searched for RCTs. Critical and important CRSwNP-related outcomes were considered. The risk of bias and the certainty of the evidence were assessed using GRADE. RCTs evaluated (dupilumab-2, omalizumab-4, mepolizumab-2, and reslizumab-1) included 1236 adults, with follow-up of 20-64 weeks. Dupilumab reduces the need for surgery (NFS) or oral corticosteroid (OCS) use (RR 0.28; 95% CI 0.20-0.39, moderate certainty) and improves with high certainty smell evaluated with UPSIT score (mean difference (MD) +10.54; 95% CI +9.24 to +11.84) and quality of life (QoL) evaluated with SNOT-22 (MD -19.14; 95% CI -22.80 to -15.47), with fewer treatment-related adverse events (TAEs) (RR 0.95; 95% CI 0.89-1.02, moderate certainty). Omalizumab reduces NFS (RR 0.85; 95% CI 0.78-0.92, high certainty), decreases OCS use (RR 0.38; 95% CI 0.10-1.38, moderate certainty), and improves high certainty smell (MD +3.84; 95% CI +3.64 to +4.04) and QoL (MD -15.65; 95% CI -16.16 to -15.13), with increased TAE (RR 1.73; 95% CI 0.60-5.03, moderate certainty). There is low certainty for mepolizumab reducing NFS (RR 0.78; 95% CI 0.64-0.94) and improving QoL (MD -13.3; 95% CI -23.93 to -2.67) and smell (MD +0.7; 95% CI -0.48 to +1.88), with increased TAEs (RR 1.64; 95% CI 0.41-6.50). The evidence for reslizumab is very uncertain.