The following is a summary of “IL-13 and IL-13–induced periostin levels are specifically decreased in patients following endoscopic sinus surgery for chronic rhinosinusitis,” published in the May 2024 issue of Allergy & Immunology by Harmon, et al.

Type 2 (T2) inflammation is crucial in developing chronic rhinosinusitis (CRS). The effects of endoscopic sinus surgery (ESS) on T2 inflammation have yet to be fully understood. For a study, researchers sought to compare T2 inflammatory biomarkers in middle meatal (MM) mucus to distinguish patients with CRS from those without CRS, identify the significant phenotypes (CRS without nasal polyps [CRSsNP] and CRS with nasal polyps [CRSwNP]), assess changes in endotypes, and determine cross-sectional and longitudinal outcomes for patients undergoing ESS.

MM mucus samples were collected from patients with CRSsNP and CRSwNP before and 6 to 12 months after ESS and compared with CRS-free control patients. T2 biomarkers were evaluated both continuously and using threshold-based definitions of T2 endotypes. The relationships between these biomarkers and patient-reported (22-Item Sinonasal Outcomes Test and Chronic Rhinosinusitis Patient-Reported Outcomes Measure) and clinician-reported (radiographic and endoscopic) severity were analyzed. Linear mixed models assessed clinical variables associated with T2 biomarker levels.

The study enrolled 154 patients with CRS (89 with CRSsNP and 65 with CRSwNP), with an average follow-up of 9 months post-ESS. Pre-ESS MM mucus samples showed higher levels of T2 mediators in patients with CRSwNP compared to CRSsNP patients and CRS-free controls. Consistent correlations were found between levels of IL-13 and IL-5, periostin and complement 5a, and eosinophil cationic protein (ECP) and eotaxin-3. IL-13, periostin, and ECP were further analyzed for their pathological significance. Following ESS, IL-13 and periostin levels significantly decreased, whereas ECP levels remained unchanged. The T2 endotype was linked to radiographic severity but did not predict clinical outcomes. CRSwNP status and African American race were associated with higher levels of IL-13 and periostin, while ECP levels were higher in patients undergoing extensive surgery.

ESS led to significant reductions in IL-13 and periostin levels in the middle meatus, indicating changes in T2 inflammation. Post-ESS T2 inflammation was associated with both patient-reported and clinician-reported severity across different CRS phenotypes, although pre-ESS T2 inflammation levels did not predict post-ESS outcomes.

Reference: jacionline.org/article/S0091-6749(23)02542-3/abstract