Tissue Interleukin-33: A Novel Potential Regulator of Innate Immunity and Biomarker of Disease Severity in Chronic Rhinosinusitis with Nasal Polyps.

BACKGROUND: Chronic rhinosinusitis with nasal polyps (CRSwNP) is a disease of real interest for researchers due to its heterogenicity and complex pathophysiological mechanisms. Identification of the factors that ensure success after treatment represents one of the main challenges in CRSwNP research. No consensus in this direction has been reached so far. Biomarkers for poor outcomes have been noted, but nonetheless, their prognostic value has not been extensively investigated, and needs to be sought. We aimed to evaluate the correlation between potential prognostic predictors for recalcitrant disease in patients with CRSwNP.

METHODS: The study group consisted of CRSwNP patients who underwent surgical treatment and nasal polyp (NP) tissue sampling. The preoperative workup included Lund-Mackay assessment, nasal endoscopy, eosinophil blood count, asthma, and environmental allergy questionnaire. Postoperatively, in subjects with poor outcomes, imagistic osteitis severity was evaluated, and IL-33 expression was measured.

RESULTS: IL-33 expression in NP was positively and significantly correlated with postoperative osteitis on CT scans ( p = 0.01). Furthermore, high osteitis CT scores were related to high blood eosinophilia ( p = 0.01). A positive strong correlation was found between postoperative osteitis and the Lund-Mackay preoperative score ( p = 0.01), as well as the nasal endoscopy score ( p = 0.01).

CONCLUSIONS: Our research analyzed the levels of polyp IL-33, relative to blood eosinophilia, overall disease severity score, and osteitis severity, in patients with CRSwNP. These variables are prognostic predictors for poor outcomes and recalcitrant disease. Considering the importance of bone involvement in CRSwNP, this research aims to provide a better insight into the correlations of osteitis with clinical and biological factors.