Type 2 Inflammatory Shift in Chronic Rhinosinusitis During 2007-2018 in Belgium

Objectives/Hypothesis Chronic rhinosinusitis (CRS) is a heterogenic disease with different inflammatory patterns depending on the presence (CRSwNP) or absence (CRSsNP) of polyps and geographical location. A shift toward type 2 endotype has been seen in Asia. We aim to investigate whether there has been type 2 shift in Belgium and to further endotype CRS based on clinical markers. Study design Prospective descriptive study. Methods Four hundred and thirty eight patients with CRS undergoing sinus surgery at Ghent University Hospital between 2007 and 2018 were included and stratified based on phenotype, comorbidities, inflammatory markers in tissue, and two different time points of surgery. Tissue samples from surgery were analyzed for type 2 markers. In a subgroup of CRSwNP blood eosinophils (EBC) was available. Results There was an increase in type 2 inflammatory markers in the latter group versus the earlier, in non-asthmatic, non-allergic CRS patients regardless of phenotype. The proportion of IL-5+ patients was elevated in the latter group in CRSwNP. Inflammatory markers and comorbidities differ between IL-5+ CRSsNP and CRSwNP subjects, no difference was seen in IL-5- CRS. EBC can together with information on comorbidities help identify type 2 CRSwNP in a clinical setting. Conclusion There is a shift toward type 2 inflammation within the CRS population over recent 8 years also in Belgium. This shift implies that we expect to see more cases of severe and difficult to treat CRS in the future. Polyp formation is not directly linked to the presence or concentrations of type 2 inflammatory markers. Clinical parameters and EBC > 300 cells/mu L can be used to identify type 2 CRSwNP. Level of Evidence 3.Laryngoscope, 2020

Automated summary

The study aims to investigate the shift towards type 2 inflammation within the CRS population in Belgium and further classify different types of CRS based on clinical markers. Findings suggest that there has been an increase in type 2 inflammatory markers in CRS patients in Belgium over recent years.