title: Dual nature of T cell-epithelium interaction in chronic rhinosinusitis.
abstract: BACKGROUND
  T-cell infiltration of submucosa, release of proinflammatory cytokines leading to epithelial activation, and contributions to inflammation are observed in chronic rhinosinusitis (CRS).
  
  
  OBJECTIVE
  Molecular mechanisms and kinetics of T-cell interaction with sinus epithelium leading to activation followed by subsequent apoptosis of epithelial cells were the focus of the current study.
  
  
  METHODS
  Primary human sinus epithelial cells and T cells generated from sinus tissues of healthy individuals and patients with CRS with or without allergy and sinus tissue biopsies were characterized in terms of activation (surface marker expression, cytokine production via real-time PCR, confocal microscopy, ELISA) and apoptosis (annexin V/7-amino-actinomycin D staining, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay, receptor expression by flow cytometry, confocal microscopy) of epithelial cells.
  
  
  RESULTS
  Primary human sinus epithelial cells isolated from patients with CRS were at an activated state with upregulated expression of HLA-DR, IFN-gamma-inducible protein 10, monokine induced by IFN-gamma, and TNF-related apoptosis-inducing ligand (TRAIL) compared with healthy individuals. The expressions of these chemokines, HLA-DR, TRAIL, and TNF receptor 2 were significantly induced by IFN-gamma, whereas TRAIL receptor 4 was downregulated. Epithelial cells started to undergo apoptosis 48 hours after IFN-gamma stimulation when the transcription of proinflammatory cytokines and chemokines decreased to initial levels. The essential factors for sinus epithelial apoptosis were T(H)1 cells and IFN-gamma. Epithelial apoptosis was enhanced by Fas-Fas-ligand and TRAIL-TRAIL receptor 2 interactions. Remarkable apoptosis of epithelial cells and shedding was observed in CRS in situ.
  
  
  CONCLUSIONS
  Epithelial cell interaction with activated T cells is a biphasic phenomenon in CRS. Initially activated T cells lead to activation and induction of proinflammatory functions of epithelial cells, and thereafter their apoptotic death, resulting in no more contribution to inflammation, takes place.
authors.affiliation: Swiss Institute of Allergy and Asthma Research, University of Zurich, Obere Strasse 22, Davos 7270, Switzerland. tomasz.basinski@siaf.uzh.ch
authors.forename: Tomasz M
authors.initials: TM
authors.lastname: Basinski
authors.forename: David
authors.initials: D
authors.lastname: Holzmann
authors.forename: Thomas
authors.initials: T
authors.lastname: Eiwegger
authors.forename: Maya
authors.initials: M
authors.lastname: Zimmermann
authors.forename: Sven
authors.initials: S
authors.lastname: Klunker
authors.forename: Norbert
authors.initials: N
authors.lastname: Meyer
authors.forename: Peter
authors.initials: P
authors.lastname: Schmid-Grendelmeier
authors.forename: Marek
authors.initials: M
authors.lastname: Jutel
authors.forename: Cezmi A
authors.initials: CA
authors.lastname: Akdis
mesh_terms: D017209:Apoptosis; D002478:Cells, Cultured; D018925:Chemokines / Q000378:metabolism; D002908:Chronic Disease; D016207:Cytokines / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000276:immunology*; D006801:Humans; D007150:Immunohistochemistry; D007371:Interferon-gamma / Q000378:metabolism; D010256:Paranasal Sinuses / Q000166:cytology / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012220:Rhinitis / Q000276:immunology*; D012852:Sinusitis / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D018925:Chemokines; D016207:Cytokines; D007371:Interferon-gamma