Improved graft survival in highly sensitized patients undergoing renal transplantation after the introduction of a clinically validated flow cytometry crossmatch

Transplantation. 2009 Apr 15;87(7):1052-6. doi: 10.1097/TP.0b013e31819d17b0.


Background: Flow cytometric techniques are increasingly used in pretransplant crossmatching, although there remains debate regarding the clinical significance and predictive value of donor-specific antibodies detected by flow cytometry. At least some of the discrepancies between published studies may arise from differences in cutoffs used and lack of standardization of the test.

Methods: We selected cut-off values for pretransplant flow cytometric crossmatching (FCXM) based on the correlation of retrospective results with the occurrence of antibody-mediated rejection. The impact on long-term renal graft survival of prospective FCXM was determined by comparing graft survival between patients crossmatched with complement-dependent cytotoxicity (CDC) only with those prospectively crossmatched with both CDC and FCXM.

Results: Chosen cut-off values gave a positive predictive value of FCXM for antibody-mediated rejection of 83%, and a negative predictive value of 90%. After the introduction of prospective B- and T-cell crossmatching by flow cytometry in addition to CDC in our center, there was a significant improvement in renal graft survival in highly sensitized patients (P=0.017). Four-year graft survival in highly sensitized patients after the introduction of FCXM was 89%, which did not differ significantly from that seen in nonsensitized patients (93%; P=0.638).

Conclusions: Our data demonstrate that prospective FCXM improves renal transplant outcome in highly sensitized patients, provided that cut-off values are carefully validated and results interpreted in the context of sensitization history and antibody screening results.

MeSH terms

  • B-Lymphocytes / immunology
  • Flow Cytometry / methods
  • Graft Survival / immunology*
  • Histocompatibility Testing*
  • Humans
  • Immunization*
  • Isoantibodies / immunology
  • Kidney Transplantation / immunology*
  • Kidney Transplantation / mortality
  • Predictive Value of Tests
  • Survival Analysis
  • Survivors
  • T-Lymphocytes / immunology


  • Isoantibodies