title: Increased IL-21 expression in chronic rhinosinusitis with nasalpolyps.
abstract: BACKGROUND
  IL-21 is a key cytokine for regulating B cell immunity, which is involved in several inflammatory conditions. This study sought to define a role for IL-21 in activated B lymphocytes and enhanced tissue eosinophilia in NP tissues during the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP).
  
  
  METHODS
  NP and uncinate process tissues were collected from 64 CRSwNP patients, 25 CRSsNP patients, and 29 control subjects. IL-21 expression was examined using IHC staining, qRT-PCR, flow cytometry, and ELISA, and its clinical implication was evaluated. Moreover, the effects of IL-21 on B cell differentiation and Ig production in cultured NP cells were examined in vitro.
  
  
  RESULTS
  The mRNA and protein levels of IL-21 were significantly increased in polyp tissues compared with control tissues (P < 0.05). Polyp IL-21 level was significantly associated with polyp size, tissue eosinophilia and asthma comorbidity, and recurrence after surgery (P < 0.05). Both Th1 and Th17 cells were the main cellular sources of IL-21 in polyp tissues. The percentage of IL-21(+) CD4(+) cells was significantly higher in polyp tissues compared with control tissues and matched PBMCs (P < 0.01). Accordingly, the percentage of CD19(+) CD20(+/-) CD38(high) cells was significantly higher in polyp tissues compared with control tissues (P < 0.01). Moreover, recombinant IL-21 significantly increased the percentage of CD19(+) CD20(+/-) CD38(high) cells (plasmablasts) and IgG and IgA production in cultured NP cells in vitro (P < 0.05).
  
  
  CONCLUSIONS
  Increased IL-21 level in polyp tissues was associated with disease severity, local B cell activation, and immunoglobulin production, suggesting that IL-21 might play an important role in promoting persistent mucosal inflammation in CRSwNP patients.
authors.affiliation: Institute of Immunology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.
authors.forename: L
authors.initials: L
authors.lastname: Xiao
authors.forename: Y
authors.initials: Y
authors.lastname: Wei
authors.forename: Y-N
authors.initials: YN
authors.lastname: Zhang
authors.forename: X
authors.initials: X
authors.lastname: Luo
authors.forename: B-Y
authors.initials: BY
authors.lastname: Yang
authors.forename: S-F
authors.initials: SF
authors.lastname: Yu
authors.forename: X-M
authors.initials: XM
authors.lastname: Wu
authors.forename: C-Y
authors.initials: CY
authors.lastname: Wu
authors.forename: H-B
authors.initials: HB
authors.lastname: Li
mesh_terms: D000328:Adult; D001402:B-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D016022:Case-Control Studies; D002908:Chronic Disease; D005260:Female; D015870:Gene Expression; D006801:Humans; D016130:Immunophenotyping; D007378:Interleukins / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009297:Nasal Mucosa / Q000378:metabolism / Q000473:pathology; D009298:Nasal Polyps / Q000150:complications / Q000175:diagnosis / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D012220:Rhinitis / Q000150:complications / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D012720:Severity of Illness Index; D012852:Sinusitis / Q000150:complications / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism; D055815:Young Adult; D000098546:Interleukin-21
chemical_list: D007378:Interleukins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D000098546:Interleukin-21
keywords: B cell; IL-21; asthma; chronic rhinosinusitis; immunoglobulin; nasal polyp; plasma cells