title: Interpretation of positive flow cytometric crossmatch in the era of the single-antigen bead assay.
abstract: BACKGROUND
  Prognosis of renal transplants with positive flow cytometric crossmatch (FCXM) remains controversial.
  
  
  METHODS
  We analyzed the outcome of these kidney transplant recipients by human leukocyte antigen (HLA) donor-specific antibodies (HLA-DSA) using single-antigen bead (SAB) assays in major histocompatibility complex classes I and II. We compared them with controls with a negative FCXM.
  
  
  RESULTS
  Forty-five patients consecutively transplanted with a positive FCXM had significantly more acute rejection episodes than the control patients (33.3% vs. 8.9%, P=0.002). Risk of acute rejection was increased with day 0 (D0) positive T-cell FCXM (odds ratio [OR]=9.04, P=0.002), D0 positive B-cell FCXM (OR=7.43, P=0.02), and D0 HLA-DSA identified by SAB assay (OR=6.5, P=0.03). The 21 patients with D0 positive FCXM and D0 HLA-DSA had more acute rejection (62%, P=0.0001) and a lower estimated glomerular filtration rate 1-year posttransplantation (P=0.0001), when compared with controls. Mainly anti-Cw and anti-DP HLA-DSA were found in patients displaying acute rejection. The remaining FCXM-positive patients displayed short-term outcomes similar to controls. The presence of HLA-DSA detected only by the SAB assay in the context of a negative FCXM crossmatch was not associated with increased risk of acute rejection.
  
  
  CONCLUSIONS
  Identification of HLA-DSA in D0 sera by the two sensitive techniques FCXM and SAB assay indicates which patients are at highest risk of subsequent acute allograft rejection and chronic allograft dysfunction.
authors.affiliation: CHU Bordeaux, Hôpital Pellegrin, Nephrology, Place Amélie Raba Léon, Bordeaux, France. lionel.couzi@chu-bordeaux.fr
authors.forename: Lionel
authors.initials: L
authors.lastname: Couzi
authors.forename: Caroline
authors.initials: C
authors.lastname: Araujo
authors.forename: Gwendaline
authors.initials: G
authors.lastname: Guidicelli
authors.forename: Thomas
authors.initials: T
authors.lastname: Bachelet
authors.forename: Karine
authors.initials: K
authors.lastname: Moreau
authors.forename: Delphine
authors.initials: D
authors.lastname: Morel
authors.forename: Grégoire
authors.initials: G
authors.lastname: Robert
authors.forename: Hervé
authors.initials: H
authors.lastname: Wallerand
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Moreau
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Taupin
authors.forename: Pierre
authors.initials: P
authors.lastname: Merville
mesh_terms: D000328:Adult; D001706:Biopsy; D005260:Female; D005434:Flow Cytometry / Q000379:methods*; D005919:Glomerular Filtration Rate / Q000502:physiology; D006084:Graft Rejection / Q000453:epidemiology / Q000276:immunology; D006650:Histocompatibility Testing / Q000379:methods*; D006801:Humans; D018189:Immunomagnetic Separation / Q000379:methods*; D015994:Incidence; D053208:Kaplan-Meier Estimate; D007668:Kidney / Q000276:immunology / Q000473:pathology / Q000502:physiology; D016030:Kidney Transplantation / Q000276:immunology* / Q000473:pathology* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D016896:Treatment Outcome