title: Cellular comparison of sinus mucosa vs polyp tissue from a single sinus cavity in chronic rhinosinusitis.
abstract: BACKGROUND
  Nasal polyposis is a common development in chronic rhinosinusitis (CRS), and sinus mucosa and polyp tissue have been used interchangeably in studies investigating CRS. However, potential differences may exist between these 2 tissue types, which have not been entirely characterized.
  
  
  METHODS
  A cross-sectional study of CRS with nasal polyposis (CRSwNP) patients undergoing endoscopic sinus surgery was conducted. Sinus mucosal biopsies and corresponding polyp tissue were obtained from the same sinus cavity via flow cytometry, single-cell suspensions identified type 2 innate lymphoid cells (ILC2s), CD4 and CD8 T cells, activated CD4 and CD8 T cells, plasma cells, plasmacytoid dendritic cells (pDCs), regulatory T cells, T follicular helper cells, B cells, and immunoglobulin A (IgA)(+) and IgG(+) B cells. Cells were measured as a percentage of CD45(+) cells. Paired nonparametric comparisons between sinus and polyp tissue were performed.
  
  
  RESULTS
  Ten patients (50% female; age 48 ± 16 years) were recruited. Significantly elevated ILC2 levels were found in polyp tissue compared to sinus mucosa (0.12 [0.07 to 0.23] vs 0.07 [0.04 to 0.16], p = 0.02), as well as plasma cells (2.25 [0.84 to 3.68] vs 1.18 [0.74 to 2.41], p = 0.01); pDCs (0.15 [0.12 to 0.50[ vs 0.04 [0.02 to 0.17], p = 0.03); activated CD8 T cells (29.22 [17.60 to 41.43] vs 16.32 [10.07 to 36.16], p = 0.04) and IgG(+) B cells (6.96 [0.06 to 11.82] vs 1.51 [0.38 to 5.13], p = 0.04). Other cell populations showed no significant differences.
  
  
  CONCLUSIONS
  Polyps have a similar cellular composition to that of mucosa. Higher levels of ILC2s, plasma cells, pDCs, activated CD8 T cells, and IgG(+) B cells in polyp tissue may be reflective of cell populations driving nasal polyp development. The cellular machinery of CRS is present in polyps and representative of the disease process. This pilot study strongly suggests that a larger study would provide significant insights into the relationship of sinus mucosa to pathogenesis of nasal polyps.
authors.affiliation: St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia; Rhinology and Skull Base Research Group, St Vincent's Centre for Applied Medical Research, University of New South Wales, Sydney, Australia.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Ho
authors.forename: Michelle
authors.initials: M
authors.lastname: Bailey
authors.forename: John
authors.initials: J
authors.lastname: Zaunders
authors.forename: Nadine
authors.initials: N
authors.lastname: Mrad
authors.forename: Raymond
authors.initials: R
authors.lastname: Sacks
authors.forename: William
authors.initials: W
authors.lastname: Sewell
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Harvey
mesh_terms: D000328:Adult; D002469:Cell Separation; D002908:Chronic Disease; D003430:Cross-Sectional Studies; D003713:Dendritic Cells / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007113:Immunity, Innate; D008213:Lymphocyte Activation; D016131:Lymphocyte Subsets / Q000276:immunology*; D008214:Lymphocytes / Q000276:immunology*; D008297:Male; D009297:Nasal Mucosa / Q000473:pathology*; D009298:Nasal Polyps / Q000473:pathology*; D010950:Plasma Cells / Q000276:immunology*; D012220:Rhinitis / Q000473:pathology*; D012852:Sinusitis / Q000473:pathology*; D018418:Th2 Cells / Q000276:immunology
keywords: chronic rhinosinusitis; flow cytometry; human; lymphocytes; mucosa; nasal polyp; sinonasal; sinus; tissue; type 2 innate lymphoid cells