Angiogenesis and eosinophilia in the nasal mucosa of patients with different clinical phenotypes of chronic rhinosinusitis

Introduction: Dense inflammatory cell infiltration and vascularization of the nasal mucosa are histological characteristics of chronic rhinosinusitis (CRS). We aimed to evaluate the association between eosinophilia and vascularization in the stroma of mucosal layer/nasal polyps (NP) and clinical parameters in patients with different phenotypes of CRS.Methodology: This cross-sectional study involved 33 patients who had CRS with NP without aspirin sensitivity (CRSwNP), 20 NP patients as a part of aspirin-exacerbated respiratory disease (AERD), and 10 patients who had CRS without NP (CRSsNP), selected for surgery. Control group consisted of 31 subjects without nasal/sinus inflammation, selected for surgery of pneumatized middle turbinate. All patients were clinically scored before surgery for nasal symptoms, quality of life (QoL) outcome and findings from computed tomography scans. NP/nasal mucosa samples of participants were immunohistochemically stained for eosinophil infiltration marker BMK13 and angiogenesis markers CD31 and CD34.Results: AERD patients had the highest level of immunoexpression for BMK13. The strongest staining pattern of CD34 was found in AERD group and the highest expression level for CD31 in CRSwNP group. We found a positive correlation between BMK13, impaired QoL and radiologically evaluated disease extent in patients with CRSwNP. Excepting CRSsNP patients, no correlation was found between the marker of tissue eosinophilia and markers of vascular proliferation.Conclusions: Patients from AERD phenotype have the highest degree of stromal eosinophilic infiltration and endothelial proliferation in comparison to other CRS phenotypes. Eosininophil infiltration marker BMK13 correlates better with the clinical parameters of CRS in comparison to the vascular proliferation markers.