Analysis of Histopathological Endotyping for Chronic Rhinosinusitis Phenotypes Based on Comorbid Asthma and Allergic Rhinitis.

Background An emerging trend in clinical research has centered on improving the characteristics of chronic rhinosinusitis (CRS) according to phenotypes and endotypes. The objective of this study is to utilize histopathological markers to better characterize CRS phenotypes that are defined by the presence or absence of comorbid bronchial asthma (BA) and allergic rhinitis (AR). Methods A prospective case-controlled study of CRS patients was conducted. For the CRS cohort, mucosal biopsies were obtained during endoscopic sinus surgery, while samples of ethmoid mucosa were collected in control patients undergoing endoscopic skull base surgery. Histopathological analysis of tissue samples determined the relative frequency of inflammatory cell types, including eosinophils, lymphocytes, neutrophils, mast cells, and plasma cells. The presence and absence of comorbid BA and AR were used to further divide CRS, allowing for further subgroup analysis. Results Of 82 recruited patients, there were 67 CRS patients and 15 controls. Significantly increased eosinophil ratios were found in CRS patients with AR, BA, or both, when compared with controls (P < .001). Conversely, CRS patients with neither comorbid diagnosis failed to demonstrate statistically significant elevations in eosinophil ratios (P > .05). Lymphocyte ratios showed a significantly inverse correlation with trends demonstrated by eosinophil ratios in all patient subgroups (P < .001). Neutrophil, mast cell, and plasma cell ratios did not show significant differences across the evaluated subgroups. Conclusions The clinical diagnosis of comorbid BA and AR may aid in better characterizing CRS endotypes without invasive testing and better direct management of the disease.