title: Profiling posttransplant circulating antibodies in kidney transplantation using donor endothelial cells.
abstract: BACKGROUND
  Pathogenesis of antibody (Ab) responses to transplant are yet not well defined. This study aimed to detect and to analyze posttransplant circulating allo-Abs reacting toward graft endothelial cells (ECs) using primary EC cultures prospectively isolated from the transplant donor at the time of transplantation.
  
  
  METHODS
  This study shows a retrospective analysis performed using a dedicated EC crossmatch (ECXM) assay that we developed for the experimental assessment of donor-specific EC-reactive Abs. Donor-specific ECXM was performed by flow cytometry on posttransplant sera (n=256) from an historical cohort of 22 kidney allograft recipients.
  
  
  RESULTS
  In this study, we show that 27.3% (6/22) of recipients have a positive ECXM that strictly correlates (100%, 6/6) with the presence of anti-human leukocyte antigen (HLA) Abs posttransplantation. ECXM identifies both donor-specific Abs (DSA; 50%) and non-DSA (50%) reactive to EC. DSA and non-DSA are mostly IgG1 and exhibit peak titers ranging from 1/8 to 1/1024. ECXM indicates that DSA correspond to anti-HLA class II Abs; this immunization is late (M3-M60) but persistent (still detected at M60). In contrast, non-DSA are non-HLA-type Abs reacting with third-party EC and reflecting an early but transient immunization (ended at M3-M12). Our findings demonstrate selective regulatory pathways initiated by anti-HLA class II and non-DSA in graft EC reflected by CCR4 and interleukin 1β up-regulation, respectively.
  
  
  CONCLUSIONS
  We provide evidence that circulating Abs in HLA-sensitized transplant recipients include both DSA and non-HLA/non-DSA able to bind to graft EC and induce specific gene transcription.
authors.affiliation: INSERM UMR643, Institute for Transplantation, Urology and Nephrology, CHU de Nantes, Université de Nantes, Faculté de Médecine, Nantes, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Canet
authors.forename: Julie
authors.initials: J
authors.lastname: Devallière
authors.forename: Nathalie
authors.initials: N
authors.lastname: Gérard
authors.forename: George
authors.initials: G
authors.lastname: Karam
authors.forename: Magali
authors.initials: M
authors.lastname: Giral
authors.forename: Béatrice
authors.initials: B
authors.lastname: Charreau
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Coupel
mesh_terms: D000328:Adult; D042783:Endothelial Cells / Q000276:immunology*; D005260:Female; D006680:HLA Antigens / Q000276:immunology*; D006650:Histocompatibility Testing; D006801:Humans; D007114:Immunization; D007518:Isoantibodies / Q000097:blood*; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D058504:Th17 Cells / Q000502:physiology; D014019:Tissue Donors
chemical_list: D006680:HLA Antigens; D007518:Isoantibodies