title: Increased frequency of CD4+ cells expressing CD161 in cancer patients.
abstract: OBJECTIVE
  Although the function of natural killer receptors on T cells infiltrating tumors and their potential effect on antitumor immunity has been investigated, little is known about T cells expressing NKR-P1A (CD161) in cancer patients. In the present study, we examined T cells expressing CD161 in the peripheral blood, the tumor tissue and in malignant effusions of patients with several types of malignancies.
  
  
  METHODS
  Expression of CD161 in CD4(+) or CD8(+) (lacking CD56) T cells isolated from peripheral blood (n = 61), tumor specimens (n = 8), and malignant effusions (n = 37) of cancer patients was examined using four-color flow cytometry. Proliferative capacity and cytokine production of purified CD4(+)CD161(+)CD56(-) cells were studied after weak or strong stimulation, with or without costimulation, in the presence or absence of interleukin 2. The possible regulatory function of activated CD4(+)CD161(+)CD56(-) cells on T-cell alloresponses was also investigated.
  
  
  RESULTS
  CD4(+) cells expressing CD161 were increased in cancer patients, compared with healthy individuals. This increase in the peripheral blood of cancer patients positively correlated with disease stage and was augmented at the tumor site. Phenotypic analysis revealed that CD4(+)CD161(+) cells are memory T cells, with low expression of activation markers. CD4(+)CD161(+) cells play an immunoregulatory role through cytokine production, because upon receiving costimulatory signals via CD28, they exert suppressive activity on autologous peripheral blood mononuclear cell alloresponses.
  
  
  CONCLUSIONS
  CD4(+)CD161(+)CD56(-) cells represent a distinct memory T-cell population significantly increased in cancer patients. Depending on the type of signals provided by the tumor microenvironment, CD4(+)CD161(+) cells may regulate the immune response.
authors.affiliation: Cancer Immunology and Immunotherapy Center, Saint Savas Cancer Hospital, Athens, Greece.
authors.forename: Eleni G
authors.initials: EG
authors.lastname: Iliopoulou
authors.forename: Michalis V
authors.initials: MV
authors.lastname: Karamouzis
authors.forename: Ioannis
authors.initials: I
authors.lastname: Missitzis
authors.forename: Alexandros
authors.initials: A
authors.lastname: Ardavanis
authors.forename: Nectaria N
authors.initials: NN
authors.lastname: Sotiriadou
authors.forename: Constantin N
authors.initials: CN
authors.lastname: Baxevanis
authors.forename: Gerasimos
authors.initials: G
authors.lastname: Rigatos
authors.forename: Michael
authors.initials: M
authors.lastname: Papamichail
authors.forename: Sonia A
authors.initials: SA
authors.lastname: Perez
mesh_terms: D000954:Antigens, Surface / Q000096:biosynthesis* / Q000276:immunology; D018106:CD28 Antigens / Q000187:drug effects / Q000276:immunology; D017252:CD3 Complex / Q000187:drug effects / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002452:Cell Count; D049109:Cell Proliferation / Q000187:drug effects; D005260:Female; D006801:Humans; D007378:Interleukins / Q000096:biosynthesis / Q000494:pharmacology; D037181:Lectins, C-Type / Q000096:biosynthesis* / Q000276:immunology; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology; D055651:NK Cell Lectin-Like Receptor Subfamily B; D009367:Neoplasm Staging; D009369:Neoplasms / Q000276:immunology*; D010641:Phenotype; D011237:Predictive Value of Tests; D013329:Structure-Activity Relationship
chemical_list: D000954:Antigens, Surface; D018106:CD28 Antigens; D017252:CD3 Complex; D007378:Interleukins; C527203:KLRB1 protein, human; D037181:Lectins, C-Type; D055651:NK Cell Lectin-Like Receptor Subfamily B