title: T lymphocytes that infiltrate nasal polyps have a specialized phenotype and produce a mixed TH1/TH2 pattern of cytokines.
abstract: BACKGROUND
  Nasal polyps (NPs) are inflammatory reactions in the nasal mucosa the etiology and pathogenesis of which remains unknown.
  
  
  OBJECTIVE
  The purpose of this study was to study in detail the phenotype and function of T lymphocytes infiltrating NPs by analyzing the expression of surface markers and cytokine secretion.
  
  
  METHODS
  NP tissue samples and peripheral blood were obtained from 18 patients. Mononuclear cells were purified from these samples, and their phenotype was investigated by triple-color immunofluorescence and flow cytometric analysis. Cytokine production was determined in cultures by using an ELISA technique.
  
  
  RESULTS
  NP lymphoid cells mainly consisted of T lymphocytes. These T lymphocytes showed a CD45RO+CD45RA- phenotype and expressed pan-T cell molecules; the CD8+ subset was predominant. NP T cells showed a lower density of CD28, CD3, and TCR-alphabeta compared with T cells from peripheral blood. NP T lymphocytes expressed the activation markers DR and CD69 and exhibited the adhesion molecule profile CD54+, CD62L-, and CD103+ CD49dlow. Virtually all NP T cells bore CD95 (FAS), but they did not undergo apoptosis, either spontaneously or induced by CD95 cross-linking with the mAb CH11. The pattern of cytokines secreted by NP T lymphocytes was characterized by the spontaneous and simultaneous production of IFN-gamma and IL-5. Neither IL-2 nor IL-4 were detectable in nonstimulated cultures.
  
  
  CONCLUSIONS
  This study defines the T lymphocytes that infiltrate NPs as memory T cells in an activated status, with homing properties related to the mucosal immune system. They are resistant to anti-CD95-mediated apoptosis and produced a mixed TH1 /TH2 cytokine pattern as defined by the simultaneous production of IFN-gamma and IL-5.
authors.affiliation: Servicio de Otorrinolaringología, Hospital de Jerez, Cadiz; and Servicio de Inmunología, Hospital Universitario Puerta del Mar.
authors.forename: A
authors.initials: A
authors.lastname: Sánchez-Segura
authors.forename: J A
authors.initials: JA
authors.lastname: Brieva
authors.forename: C
authors.initials: C
authors.lastname: Rodríguez
mesh_terms: D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000032:analysis; D002465:Cell Movement / Q000276:immunology*; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis*; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D008297:Male; D008875:Middle Aged; D009298:Nasal Polyps / Q000276:immunology* / Q000473:pathology; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000473:pathology*; D018417:Th1 Cells / Q000378:metabolism*; D018418:Th2 Cells / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; D016207:Cytokines