title: Accumulation of effector memory CD8+ T cells in nasal polyps.
abstract: BACKGROUND
  T lymphocytes are prevalent in sinus mucosa and are implicated in chronic rhinosinusitis (CRS) pathogenesis. However, the major T-cell subpopulations, helper (CD4+) and cytotoxic (CD8+), have not been adequately examined in CRS. This study was designed to characterize human sinus mucosa and peripheral blood (PB) CD4+ and CD8+ T cells and their level of differentiation in CRS with nasal polyps (NPs), CRS without NPs, and control patients.
  
  
  METHODS
  A prospective study was performed. Percentages of CD4+ and CD8+ T cells and their levels of differentiation were analyzed in sinus mucosa and PB by flow cytometry. Cell populations were defined as naive, central memory, effector memory, and effector T cells using cell surface markers CD45RA, CD62L, and CD27. The influence of coexisting allergy, sinus eosinophilic mucus (EM), and culture results were examined.
  
  
  RESULTS
  In all patients, sinus mucosa had a lower percentage of CD4+ and a higher percentage of CD8+ T cells compared with PB. However, CRS with NPs (n = 86) had a significantly higher percentage of mucosal CD8+ T cells compared with CRS without NPs (n = 40) in control (n = 13) patients (p < 0.0001). Effector memory T cells were increased in sinuses compared with PB in all patients; however, the percentage of effector memory CD8+ T cells was greatest in CRS with NP mucosa (p = 0.002). Surprisingly coexisting allergy or culture results did not influence the mucosal T-cell phenotype. CRS with NP patients with sinus EM had a significantly higher percentage of mucosal CD8+ T cells.
  
  
  CONCLUSIONS
  Sinus mucosa in CRS with NPs is characterized by a significant enrichment of CD8+ T cells and a relative deficiency of CD4+ T cells. The majority of NP CD8+ T cells had a terminally differentiated, mature, effector memory phenotype, which raises the question, whether these cells are pathogenic or appear as a consequence of inflammation, independent of the presence of allergy or positive microbial culture.
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, University of Adelaide, South Australia, Australia.
authors.forename: Harshita
authors.initials: H
authors.lastname: Pant
authors.forename: Amy
authors.initials: A
authors.lastname: Hughes
authors.forename: Dijana
authors.initials: D
authors.lastname: Miljkovic
authors.forename: Mark
authors.initials: M
authors.lastname: Schembri
authors.forename: Peter
authors.initials: P
authors.lastname: Wormald
authors.forename: Peta
authors.initials: P
authors.lastname: Macardle
authors.forename: Randall
authors.initials: R
authors.lastname: Grose
authors.forename: Heddy
authors.initials: H
authors.lastname: Zola
authors.forename: Doreen
authors.initials: D
authors.lastname: Krumbiegel
mesh_terms: D000328:Adult; D000368:Aged; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002454:Cell Differentiation; D002465:Cell Movement; D002469:Cell Separation; D002908:Chronic Disease; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007156:Immunologic Memory; D016130:Immunophenotyping; D008297:Male; D008875:Middle Aged; D009297:Nasal Mucosa / Q000276:immunology*; D009298:Nasal Polyps / Q000276:immunology*; D011446:Prospective Studies; D012220:Rhinitis / Q000276:immunology*; D012852:Sinusitis / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology*