title: Increased frequency of human leukocyte antigen-E inhibitory receptor CD94/NKG2A-expressing peritoneal natural killer cells in patients with endometriosis.
abstract: OBJECTIVE
  To analyze the frequency of peritoneal natural killer (NK) cells expressing the human leukocyte antigen (HLA)-E receptor CD94/NKG2A in patients with endometriosis.
  
  
  METHODS
  Case-control study.
  
  
  METHODS
  University hospital.
  
  
  METHODS
  Stage III and stage IV endometriosis, according to the revised American Society for Reproductive Medicine classification, was laparoscopically and histologically confirmed in 11 and 9 patients, respectively; 13 subjects without endometriosis were selected for the control group.
  
  
  METHODS
  Collection of peripheral venous blood, peritoneal fluid, endometriotic tissue, and normal endometrium in subjects undergoing laparoscopy.
  
  
  METHODS
  Surface expression levels of CD94/NKG2A and CD94/NKG2C were detected by three-color cytofluorometric analysis. Semiquantitative HLA-E messenger RNA expression analysis was performed in endometriotic lesions and in eutopic endometrium. NK cell-mediated cytotoxic activity toward HLA-E positive target, DT360 cell line, was also determined.
  
  
  RESULTS
  In women with endometriosis, the percentage of CD94/NKG2A-positive peritoneal NK cells was significantly higher than in the control group. The CD94/NKG2A ligand, HLA-E, was detected at high levels in endometriotic tissue as messenger RNA transcript. Target cells bearing HLA-E were resistant to NK cell-mediated lysis in a CD94/NKG2A-dependent manner.
  
  
  CONCLUSIONS
  Increased expression of CD94/NKG2A in peritoneal NK cells may mediate the resistance of endometriotic tissue to NK cell-mediated lysis, thus contributing to the progression of the disease.
authors: Department of Experimental Medicine, University "La Sapienza," Rome, Italy. ricciarda.galandrini@uniroma1.it
authors: Ricciarda
authors: R
authors: Galandrini
authors: Maria Grazia
authors: MG
authors: Porpora
authors: Antonella
authors: A
authors: Stoppacciaro
authors: Federica
authors: F
authors: Micucci
authors: Cristina
authors: C
authors: Capuano
authors: Ilaria
authors: I
authors: Tassi
authors: Alessia
authors: A
authors: Di Felice
authors: Pierluigi
authors: P
authors: Benedetti-Panici
authors: Angela
authors: A
authors: Santoni
mesh_terms: D000328:Adult; D001202:Ascitic Fluid / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D016022:Case-Control Studies; D018450:Disease Progression; D004715:Endometriosis / Q000097:blood / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D005260:Female; D006680:HLA Antigens / Q000235:genetics / Q000378:metabolism; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007108:Immune Tolerance / Q000276:immunology; D007111:Immunity, Cellular / Q000276:immunology; D007694:Killer Cells, Natural / Q000378:metabolism / Q000473:pathology*; D018655:Lymphocyte Count; D008875:Middle Aged; D055654:NK Cell Lectin-Like Receptor Subfamily C; D051920:NK Cell Lectin-Like Receptor Subfamily D / Q000097:blood / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D011971:Receptors, Immunologic / Q000097:blood / Q000378:metabolism*; D055607:Receptors, Natural Killer Cell; D000097625:HLA-E Antigens
chemical_list: D006680:HLA Antigens; D015395:Histocompatibility Antigens Class I; D055654:NK Cell Lectin-Like Receptor Subfamily C; D051920:NK Cell Lectin-Like Receptor Subfamily D; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D055607:Receptors, Natural Killer Cell; D000097625:HLA-E Antigens; C527054:KLRC1 protein, human; C527059:KLRC2 protein, human