title: Clinical relevance and IgG subclass determination of non-HLA antibodies identified using endothelial cell precursors isolated from donor blood.
abstract: BACKGROUND
  ABO and human leukocyte antigen (HLA) alloantibodies provide major immunologic barriers to successful transplantation; however, there is increasing recognition for the role of anti-endothelial cell antibodies (AECAs) in allograft rejection. We investigated the relationship between AECAs identified using donor-derived endothelial cell precursors (ECPs) and kidney allograft rejection and function.
  
  
  METHODS
  Sixty live donor kidney recipients were tested pretransplant for AECAs and HLA-antibodies using flow cytometric crossmatch tests and solid-phase bead immunoassays. Renal allograft function was assessed by serum creatinine (SCr) values collected at early (mean, 50 days) and late (mean, 815 days) time points posttransplant and by incidence and type of rejection. Immunoglobulin G (IgG) subtype determination of both AECAs and HLA antibodies bound to ECPs was performed using flow cytometry.
  
  
  RESULTS
  Fourteen patients (23%) tested positive for donor-reactive IgG AECAs and had statistically higher SCr values and incidences of cellular rejection early posttransplant compared with 46 patients who tested negative (P=0.014 and P<0.05). SCr values were not statistically different late posttransplant. IgG subclass determination showed AECAs to be enriched for IgG2 and IgG4, subclasses that do not activate complement effectively. Detection of donor-reactive immunoglobulin M (IgM) AECAs did not correlate with increased SCr or incidence of rejection.
  
  
  CONCLUSIONS
  Crossmatch tests performed using donor-derived ECPs allow for the identification of alloantibodies that are associated with cellular rejection and are distinct from alloantibodies detected using lymphocytes.
authors.affiliation: Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA. ajackson@jhmi.edu
authors.forename: Annette M
authors.initials: AM
authors.lastname: Jackson
authors.forename: Donna P
authors.initials: DP
authors.lastname: Lucas
authors.forename: J Keith
authors.initials: JK
authors.lastname: Melancon
authors.forename: Niraj M
authors.initials: NM
authors.lastname: Desai
mesh_terms: D000328:Adult; D053687:Adult Stem Cells / Q000276:immunology; D000368:Aged; D003167:Complement Activation; D003404:Creatinine / Q000097:blood; D042783:Endothelial Cells / Q000276:immunology; D005260:Female; D006084:Graft Rejection / Q000209:etiology / Q000276:immunology; D006680:HLA Antigens / Q000276:immunology; D006650:Histocompatibility Testing; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000145:classification*; D007518:Isoantibodies / Q000097:blood / Q000145:classification*; D016030:Kidney Transplantation / Q000009:adverse effects / Q000276:immunology* / Q000502:physiology; D019520:Living Donors; D008297:Male; D008875:Middle Aged
chemical_list: D006680:HLA Antigens; D007074:Immunoglobulin G; D007518:Isoantibodies; D003404:Creatinine