Fibroblast levels are increased in chronic rhinosinusitis with nasal polyps and are associated with worse subjective disease severity

Background: Fibroblasts are implicated in tissue remodeling and recruitment of inflammatory cells in chronic rhinosinusitis (CRS). Populations of fibroblasts remain unquantified in CRS subtypes. The objectives of this study were to measure fibroblast populations in subtypes of CRS, and to investigate the association between fibroblasts and disease severity. Methods: Patients undergoing endoscopic sinus surgery (ESS) for CRS were prospectively enrolled from January 2011 to December 2014. Control subjects included patients undergoing endoscopic surgery for non-inflammatory conditions such as cerebrospinal fluid leak repair or non-hormone-secreting pituitary tumors. Patients completed 22-item Sino-Nasal Outcome Test (SNOT-22) questionnaires prior to surgery. Blood and tissue biopsies were taken during surgery. Percent of sinonasal fibroblasts was determined via flow cytometry by selecting fibroblast-specific protein (FSP)-positive and Mucin 1 (MUC1)-negative cells. Results: A total of 69 patients were enrolled: control (n = 24), CRS without nasal polyps (CRSsNP) (n = 13), CRS with nasal polyps (CRSwNP) (n = 22), and allergic fungal rhinosinusitis (AFRS) (n = 10). Patients with CRSwNP had significantly more fibroblasts than both control (p < 0.001) and CRSsNP (p < 0.01). Patients with AFRS had the most fibroblasts when compared to control (p < 0.0001), CRSsNP (p < 0.0001), and CRSwNP (p < 0.05). Atopy and asthma were not associated with increased fibroblasts in CRSwNP (p = 0.21, p = 0.26, respectively). Increased fibroblasts correlated with subjective disease severity as measured by SNOT-22 for CRSwNP (p = 0.003) and AFRS (p = 0.048). Conclusion: Sinonasal fibroblasts are increased in CRSwNP and AFRS compared to control and CRSsNP. Increased fibroblasts correlated with worse quality of life in CRSwNP and AFRS.