title: [Variation in NK cell number and function in individuals with recurrent or severe infections].
abstract: BACKGROUND
  The information about defects affecting natural killer cell (NK) development and activity in patients with an abnormal increase of recurrent infections is scarce.
  
  
  OBJECTIVE
  To perform a systematic analysis of NK abnormalities in patients with recurrent infections.
  
  
  METHODS
  Our study enrolled twenty patients with severe or recurrent viral infections. Natural killer cell subsets, surface receptors expression and cytotoxicity were analyzed. Results were compared with those from age- and sex-matched healthy controls.
  
  
  RESULTS
  Transient alterations were observed in the percentages and absolute numbers of NK cells in patients with infection active episodes. We also described five patients with stable disturbances in the distribution of NK cell subpopulations. These defects are mainly due to a decrease in the CD56 dim CD16 bright cells in peripheral blood. In addition, NK cell function abnormalities were observed in some patients, however, those were always transient and mainly associated to active disease.
  
  
  CONCLUSIONS
  These findings demonstrate transient alterations in the percentages and absolute numbers of NK cells in patients with recurrent or severe infection. Also, stable disturbances in CD56 dim CD16 bright NK cells are observed in these patients. Nevertheless, these parameters must be thoroughly studied to determine the mechanisms that entail these immune abnormalities and investigate how they alter the immune response.
authors: Grupo de Inmunodeficiencias Primarias, Universidad de Antioquia, Medellín, Colombia.
authors: Isaura P
authors: IP
authors: Sánchez
authors: Grupo de Inmunodeficiencias Primarias, Universidad de Antioquia, Medellín, Colombia.
authors: Lucía C
authors: LC
authors: Leal-Esteban
authors: Grupo de Inmunodeficiencias Primarias, Universidad de Antioquia, Medellín, Colombia.
authors: Julio C
authors: JC
authors: Orrego-Arango
authors: Infectología Pediátrica, Hospital Pablo Tobón Uribe, Medellín, Colombia.
authors: Carlos G
authors: CG
authors: Garcés-Samudio
authors: Facultad Nacional de Salud Pública, Universidad de Antioquia, Medellín, Colombia.
authors: Ruben Darío
authors: RD
authors: Gómez-Arias
authors: Grupo de Inmunodeficiencias Primarias, Universidad de Antioquia, Medellín, Colombia.
authors: Jose Luis
authors: JL
authors: Franco
authors: Grupo de Inmunodeficiencias Primarias, Universidad de Antioquia, Medellín, Colombia.
authors: Claudia M
authors: CM
authors: Trujillo-Vargas
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007694:Killer Cells, Natural / Q000502:physiology*; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012720:Severity of Illness Index; D014777:Virus Diseases / Q000276:immunology*; D055815:Young Adult