A Review of Classification Schemes for Chronic Rhinosinusitis with Nasal Polyposis Endotypes

Abstract

Objective: The recent development of endotypes to categorize disease variants of chronic rhinosinusitis (CRS) reflects an evolving understanding of the various pathophysiologic and pathogenetic mechanisms that contribute to the clinical heterogeneity of CRS manifestations. This review highlights popular endotype-based criteria used to define different CRS with nasal polyposis (CRSwNP) subtypes and further discusses the emerging therapeutic advances for each classificatory approach.

Data sources: PubMed literature review.

Methods: A review of the current literature was conducted to determine present-day uses of immunologic and molecular profiles in the CRSwNP disease spectrum to identify specific endotypes.

Results: Four distinct but overlapping classification schemes have emerged to define endotypes within the CRSwNP phenotype: 1) type 2 cytokine-based approach, 2) eosinophil-based approach, 3) immunoglobulin (Ig)E-based approach, and 4) cysteinyl based approach. The identification of key inflammatory biomarkers related to these CRSwNP endotypes has broadened the classification of CRS beyond common phenotypic expressions. Furthermore, CRSwNP endotypes may improve the selection of CRSwNP patients who are suitable candidates for biomarker-specific treatment options, such as anti-interleukin-5; anti-IgE; and platelet-directed therapies.

Conclusion: Chronic rhinosinusitis endotyping with key biomarker patterns of inflammation allows for improved diagnostic and potentially therapeutic classifications of CRSwNP variants.

Keywords: Chronic rhinosinusitis; asthma; biologic therapy; endotypes; eosinophils; molecular biomarkers; nasal polyps; phenotypes.

Figure 1

Highlighted cellular and molecular pathways in the type 1 and type 2 inflammatory cascades for patients with chronic rhinosinusitis. The typical chronic rhinosinusitis patients in North America and Europe follow a type 2 inflammatory response with prevalent eosinophilic mucin. Type 1 inflammation, classically see in Asian patients, manifests a predominately neutrophilic response. CCL = chemokine ligand; CXCL = chemokine ligand; ILC2 = type 2 innate lymphoid cell; S = Siglec‐8 receptor; TSLP = thymic stromal lymphopoietin; T_H0 5 Undifferentiated T helper cell; T_H1 5 T helper 1 cell; T_H2 5 T helper 2 cell; T_H17 5 T helper 17 cell; IFNγ 5 interferon gamma.