According to phenotypes and endotypes, an emerging trend in clinical research has centered on improving the CRS. This study aims to utilize histopathological markers to characterize better CRS phenotypes defined by the presence or absence of comorbid BA and AR.

Researchers conducted a prospective case-controlled study of CRS patients. For the CRS cohort, mucosal biopsies were obtained during endoscopic sinus surgery, while researchers collected samples of ethmoid mucosa 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.

Researchers recruited a total of 87 patients, and there were 67 CRS patients and 15 controls. Researchers found significantly increased eosinophil ratios in CRS patients with AR, BA, or both when compared with controls. Lymphocyte ratios showed a significant inverse correlation with trends demonstrated by eosinophil ratios in all patient subgroups. Neutrophil, mast cell, and plasma cell ratios did not show significant differences across the evaluated subgroups.

The study concluded that clinical diagnosis of comorbid BA and AR might aid in better characterizing CRS endotypes without invasive testing and better direct management of the disease.