Investigating the Role of the Sinus Microbiome and Cytokine Profile in the SNOT-22 Response After Functional Endoscopic Sinus Surgery in Chronic Rhinosinusitis Patients.

: Functional endoscopic sinus surgery (FESS) is the treatment of choice for medically refractory CRS. However, the success rate of FESS is dependent on both baseline medical and demographic characteristics. Consequently, we performed an analysis of systemic/nasal cytokines and the sinus microbiome to assess their impact on the SNOT-22 response after functional endoscopic sinus surgery (FESS). : A prospective observational study was performed on 44 patients with chronic rhinosinusitis undergoing FESS between December 2021 and September 2022. Diseased sinus tissue from 25 patients was subjected to whole-exome sequencing (WES) for taxonomical profiling of the sinus bacterial composition. Additional data collection included demographics, comorbidities, baseline sinonasal outcome test scores, post-operative sinonasal outcome test scores (at 3-4 months), and nasal/systemic cytokines. : Our analysis demonstrated that CRSwNP patients in the surgical responder cohort had statistically significantly higher median [P25, P75] levels of intra-nasal IL-5, indicating type 2 sinonasal disease (63 pg/μL [28, 118] versus 17 pg/μL [16.6, 18], = 0.04). At the genus level, the relative abundance of was significantly higher in the surgical non-responder cohort compared to the responder group. An ROC curve was highly accurate at distinguishing responders versus non-responders to FESS based on a microbiota-based random forest model (AUC = 0.92). : Intra-nasal IL-5 levels and the bacterial composition of the sinus microbiome may be important predictors of symptomatic response after sinus surgery.