title: The characterization of IL-17A expression in patients with chronic rhinosinusitis with nasal polyps.
abstract: BACKGROUND
  Interleukin (IL)-17A, mainly produced by Th17 cells, was previously described as an inflammatory cytokine that induces a profile of proinflammatory cytokines, chemokines, and metalloproteinases. Recent studies have revealed that IL-17 is correlated with inflammatory lung disorders by triggering an accumulation of neutrophils. More recently, we have shown that the expression of IL-17 may be involved in the development of nasal polyps (NPs). Here, we describe the characterization of IL-17 expression in patients with chronic rhinosinusitis with nasal polyps (CRSwNPs) from northeast China.
  
  
  METHODS
  Histopathological observations and immunohistochemical (IHC) staining for IL-17, IL-17RD, myeloperoxidase, and CD68 were performed on 52 specimens (42 NPs and 10 specimens of middle turbinate as normal control). Double IHC staining was performed to determine which cells expressed IL-17. The serum expression levels of IL-17 were determined by ELISA and the mRNA expression of IL-17 and Th17 cells transcription factor retinoid acid-related orphan receptor C (RORc) was determined by real-time quantitative polymerase chain reaction.
  
  
  RESULTS
  42.9% of CRSwNP specimens presented eosinophilic inflammation; 35.7% of CRSwNP specimens presented neutrophilic inflammation. Relatively higher mRNA expression levels of IL-17 and RORc were seen in CRSwNPs compared with the controls. A marked increase of IL-17 and IL-17RD proteins (p < 0.01) were seen in CRSwNP group. The expression levels of IL-17 and RORc did not differ between eosinophilic and noneosinophilic CRSwNPs (p > 0.05). However, high expression levels of IL-17RD were seen in noneosinophilic CRSwNPs compared with eosinophilic CRSwNPs (p < 0.05). The serum expression of IL-17 in CRSwNP patients was similar to healthy controls. The IL-17 expressing cells mainly were the macrophages as shown by double IHC staining.
  
  
  CONCLUSIONS
  Chinese CRSwNP patients showed an enhanced Th17 response regardless of eosinophilic or noneosinophilic inflammation. IL-17 may be involved in the development of NPs through its local immune modulation.
authors.affiliation: Department of Otorhinolaryngology and Head and Neck Surgery, China-Japan Union Hospital of Jilin University, Changchun, China.
authors.forename: Xiao-Dan
authors.initials: XD
authors.lastname: Jiang
authors.forename: Guang-Yu
authors.initials: GY
authors.lastname: Li
authors.forename: Lin
authors.initials: L
authors.lastname: Li
authors.forename: Zhen
authors.initials: Z
authors.lastname: Dong
authors.forename: Dong-Dong
authors.initials: DD
authors.lastname: Zhu
mesh_terms: D000328:Adult; D002908:Chronic Disease; D004804:Eosinophils / Q000473:pathology; D005260:Female; D006801:Humans; D020381:Interleukin-17 / Q000276:immunology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009298:Nasal Polyps / Q000209:etiology / Q000276:immunology* / Q000503:physiopathology; D009504:Neutrophils / Q000473:pathology; D057132:Nuclear Receptor Subfamily 1, Group F, Member 3 / Q000378:metabolism; D017410:Practice Guidelines as Topic; D012220:Rhinitis / Q000150:complications / Q000276:immunology* / Q000503:physiopathology; D012852:Sinusitis / Q000150:complications / Q000276:immunology* / Q000503:physiopathology; D058504:Th17 Cells / Q000276:immunology / Q000378:metabolism* / Q000473:pathology
chemical_list: D020381:Interleukin-17; D057132:Nuclear Receptor Subfamily 1, Group F, Member 3; C539900:RORC protein, human