title: Decreased CD161 activating and increased CD158a inhibitory receptor expression on NK cells underlies impaired NK cell cytotoxicity in patients with multiple myeloma.
abstract: OBJECTIVE
  As innate immune cells natural killer (NK), NK-like T and CTLγδ are important in antitumour response in multiple myeloma (MM), the aim of this study was to investigate some functional and phenotypical characteristics of these cells in MM.
  
  
  METHODS
  29 patients with MM prior to therapy, in clinical stage I-III and 15 healthy controls (HCs) were investigated. Percent of immune cells in peripheral blood, NK cell activity, expression of activating (CD161) and inhibitory (CD158a, CD158b) NK cell receptors on CD3-CD16+NK cells were evaluated using 51-chromium-release assay and by flow cytometry. Production of interleukin (IL) 2 and tumour necrosis factor (TNF)α was analysed in supernatants from in vitro activated peripheral blood mononuclear cells.
  
  
  RESULTS
  In patients with MM the percent of NK cells and their two subsets did not differ from controls, while NK-like T and CTLγδ cells were significantly decreased. Significant impairment of NK cell cytotoxicity, CD107a expression and interferon γ intracellular level was also shown. There was a significant decrease in CD161 and an increase in CD158a receptor expression on NK cells in these patients. Also IL-2 production was lowest in clinical stage III. However, TNF-α production did not differ between patients and HCs.
  
  
  CONCLUSIONS
  Altered expression of CD161 activating and CD158a KIR inhibitory receptor is responsible for impaired antitumour activity of NK cells in MM patients. These new biomarkers may be helpful for patient selection for immunotherapy with cytokines, and novel KIR blocking monoclonal antibodies that enhance NK cell antimyeloma activity and provide clinical benefit.
authors.affiliation: Department of Experimental Oncology, Institute of Oncology and Radiology of Serbia, Belgrade, Serbia Faculty of Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: Gordana
authors.initials: G
authors.lastname: Konjević
authors.affiliation: Department of Experimental Oncology, Institute of Oncology and Radiology of Serbia, Belgrade, Serbia.
authors.forename: Ana
authors.initials: A
authors.lastname: Vuletić
authors.affiliation: Department of Experimental Oncology, Institute of Oncology and Radiology of Serbia, Belgrade, Serbia.
authors.forename: Katarina
authors.initials: K
authors.lastname: Mirjačić Martinović
authors.affiliation: Faculty of Medicine, University of Belgrade, Belgrade, Serbia Institute of Hematology, Clinical Center Serbia, Belgrade, Serbia.
authors.forename: Nataša
authors.initials: N
authors.lastname: Colović
authors.affiliation: Faculty of Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: Milica
authors.initials: M
authors.lastname: Čolović
authors.affiliation: Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Jurišić
keywords: CYTOKINES; CYTOMETRY; DIAGNOSIS; ELISA; MYELOMA