title: Soluble Fas ligand is associated with natural killer cell dynamics in coronary artery disease.
abstract: OBJECTIVE
  Apoptosis of natural killer (NK) cells is increased in patients with coronary artery disease (CAD) and may explain why NK cell levels are altered in these patients. Soluble forms of Fas and Fas ligand (L) are considered as markers of apoptosis. Here, we investigated whether plasma levels of Fas and FasL were associated with NK cell apoptosis and NK cell levels in CAD patients.
  
  
  METHODS
  Fas and FasL in plasma were determined by ELISA in 2 cohorts of CAD patients; one longitudinal study measuring circulating NK cells and apoptotic NK cells by flow cytometry 1 day, 3 months and 12 months after a coronary event and one cross-sectional study measuring NK cell apoptosis ex vivo. Both studies included matched healthy controls. Fas and FasL were also determined in supernatants from NK cells undergoing cytokine-induced apoptosis in cell culture.
  
  
  RESULTS
  In the 12-month longitudinal study, plasma FasL increased by 15% (p<0.001) and NK cell levels by 31% (p<0.05) while plasma Fas did not change. Plasma FasL and NK cell levels were significantly related at 3 months and 12 months, r=0.40, p<0.01. Furthermore, plasma FasL, but not plasma Fas, correlated with NK cell apoptosis ex vivo in CAD patients, r=0.54, p<0.05. In vitro, cytokine-induced apoptosis of NK cells resulted in abundant release of FasL.
  
  
  CONCLUSIONS
  In CAD patients, FasL in plasma is associated with both apoptotic susceptibility of NK cells and dynamic changes in circulating NK cells. NK cells are also themselves a potential source of soluble FasL. Our findings link NK cell status to a soluble marker with possible atheroprotective effects thereby supporting a beneficial role of NK cells in CAD.
authors.affiliation: Department of Medical and Health Sciences, Division of Cardiovascular Medicine, Faculty of Health Sciences, Linköping University, SE-58185 Linköping, Sweden.
authors.forename: Aleksander
authors.initials: A
authors.lastname: Szymanowski
authors.affiliation: Department of Clinical and Experimental Medicine, Division of Experimental Pathology, Faculty of Health Sciences, Linköping University, SE-58185 Linköping, Sweden; Department of Gynecology and Obstetrics, County Council of Östergötland, SE-58185 Linköping, Sweden.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Medical and Health Sciences, Division of Cardiovascular Medicine, Faculty of Health Sciences, Linköping University, SE-58185 Linköping, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Lundberg
authors.affiliation: Department of Medical and Health Sciences, Division of Cardiovascular Medicine, Faculty of Health Sciences, Linköping University, SE-58185 Linköping, Sweden.
authors.forename: Chamilly
authors.initials: C
authors.lastname: Evaldsson
authors.affiliation: Department of Medical and Health Sciences, Division of Cardiovascular Medicine, Faculty of Health Sciences, Linköping University, SE-58185 Linköping, Sweden.
authors.forename: Lennart
authors.initials: L
authors.lastname: Nilsson
authors.affiliation: Department of Clinical and Experimental Medicine, Division of Clinical Immunology, Faculty of Health Sciences, Linköping University, SE-58185 Linköping, Sweden; Department of Clinical Immunology and Transfusion Medicine, County Council of Östergötland, SE-58185 Linköping, Sweden.
authors.forename: Karin
authors.initials: K
authors.lastname: Backteman
authors.affiliation: Department of Clinical and Experimental Medicine, Division of Clinical Immunology, Faculty of Health Sciences, Linköping University, SE-58185 Linköping, Sweden; Department of Clinical Immunology and Transfusion Medicine, County Council of Östergötland, SE-58185 Linköping, Sweden.
authors.forename: Jan
authors.initials: J
authors.lastname: Ernerudh
authors.affiliation: Department of Medical and Health Sciences, Division of Cardiovascular Medicine, Faculty of Health Sciences, Linköping University, SE-58185 Linköping, Sweden. Electronic address: lena.jonasson@liu.se.
authors.forename: Lena
authors.initials: L
authors.lastname: Jonasson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis; D015331:Cohort Studies; D003289:Convalescence; D003324:Coronary Artery Disease / Q000097:blood* / Q000276:immunology / Q000628:therapy; D003430:Cross-Sectional Studies; D053222:Fas Ligand Protein / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D018664:Interleukin-12 / Q000494:pharmacology; D019409:Interleukin-15 / Q000494:pharmacology; D015850:Interleukin-6 / Q000097:blood; D007694:Killer Cells, Natural / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D013548:Sweden; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D019014:fas Receptor / Q000097:blood*
chemical_list: C491901:FAS protein, human; C505661:FASLG protein, human; D053222:Fas Ligand Protein; C508600:IL6 protein, human; D019409:Interleukin-15; D015850:Interleukin-6; D019014:fas Receptor; D018664:Interleukin-12
keywords: Acute coronary syndrome; Apoptosis; Coronary artery disease; Immune system; Leukocytes; Natural killer cells