title: Myocardial HLA-G reliably indicates a low risk of acute cellular rejection in heart transplant recipients.
abstract: BACKGROUND
  Human leukocyte antigen-G (HLA-G), a non-classical MHC I protein with restricted tissue expression, plays an essential role in immune tolerance and has been negatively associated with acute and chronic rejection after heart transplantation. We assessed myocardial HLA-G expression in adult heart transplant patients in an attempt to determine the value of this protein in identifying patients with a low risk of acute cellular rejection.
  
  
  METHODS
  Two groups of patients were included in this study. Group A (non-rejecting) included 29 patients who had no moderate or severe rejection episodes (ISHLT Grade <2R) post-transplant. Group B (rejecting) included 38 patients with at least two moderate or severe rejection episodes (Grade >or=2R) within a 1-year period. Expression of HLA-G in three myocardial biopsies post-transplant from each patient was determined through immunohistochemical staining.
  
  
  RESULTS
  In Group A, 86% of patients had HLA-G(+) biopsies compared with 11% of patients in Group B (p < 0.001; sensitivity 86%, specificity 87%). Whereas 60% of non-rejecting HLA-G(+) patients had at least two positive biopsies, all rejecting HLA-G(+) patients had only one positive biopsy.
  
  
  CONCLUSIONS
  There is a significant negative association between myocardial HLA-G expression and acute cellular rejection after cardiac transplantation. Detection of HLA-G appears to reliably indicate a low risk of developing moderate or severe allograft rejection and may, subsequently, allow for a reduced immunosuppressive regimen.
authors.affiliation: Heart Transplant Program, Peter Munk Cardiac Centre, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada.
authors.forename: Rohit
authors.initials: R
authors.lastname: Sheshgiri
authors.forename: Nathalie
authors.initials: N
authors.lastname: Rouas-Freiss
authors.forename: Vivek
authors.initials: V
authors.lastname: Rao
authors.forename: Jagdish
authors.initials: J
authors.lastname: Butany
authors.forename: Danny
authors.initials: D
authors.lastname: Ramzy
authors.forename: Irene
authors.initials: I
authors.lastname: Krawice-Radanne
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Ross
authors.forename: Edgardo D
authors.initials: ED
authors.lastname: Carosella
authors.forename: Diego H
authors.initials: DH
authors.lastname: Delgado
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D015870:Gene Expression; D006084:Graft Rejection / Q000235:genetics* / Q000276:immunology*; D006680:HLA Antigens / Q000276:immunology*; D059951:HLA-G Antigens; D016027:Heart Transplantation / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D012307:Risk Factors
chemical_list: D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I