Endotypes of Chronic Rhinosinusitis; relationships to disease
phenotypes, pathogenesis, clinical findings and treatment approaches.
Abstract
Chronic rhinosinusitis (CRS) is a common clinical syndrome that produces
significant morbidity and costs to our health system. The study of CRS
has progressed from an era focused on phenotype to include endotype
based information. Phenotypic classification has identified clinical
heterogeneity in CRS based on endoscopically observed features such as
presence of nasal polyps, presence of comorbid or systemic diseases and
timing of disease onset. More recently, laboratory-based findings have
established CRS endotype based upon specific mechanisms or molecular
biomarkers. Understanding the basis of widespread heterogeneity in the
manifestations of CRS is advanced by findings that the three main
endotypes, Type 1, 2 and 3, orchestrate the expression of three distinct
large sets of genes. The development and use of improved methods of
endotyping disease in the clinic is ushering in an expansion of the use
of biological therapies targeting Type 2 inflammation now and perhaps
other inflammatory endotypes in the near future. The purpose of this
review is to discuss the phenotypic and endotypic heterogeneity of CRS
from the perspective of advancing the understanding of the pathogenesis
and improvement of treatment approaches and outcomes.