Comparison of Complement-dependent Cytotoxic and Flow-cytometry Crossmatch Results Before Cadaveric Kidney Transplantation

Abstract

AimThe presence of HLA donor-specific antibodies (DSA) before kidney transplantation decreases graft survival. In this study, we compared crossmatch results of kidney transplantation candidates, for cadaveric renal donation between March 10, 2012, and September 7, 2012. Material and MethodThe 47 kidney transplantation candidates tested for crossmatch included 10 for cadaveric donor organs. Two crossmatch methods were performed: complement-dependent cytotoxic crossmatch (CDCXM) and flow cytometry crossmatch (FCXM). Spleen cells were used as the source of lymphocytes for all crossmatch tests. ResultsThe T and B cell ratios isolated from spleen were 38.8% and 34.8%, respectively. The concordance ratio of the two methods was 76.6% with 23.4% discordant results. Regarding the discordant results, 4.2% were positive CDCXM but negative FCXM; 191%, negative CDCXM but positive FCXM. All patients displaying positive crossmatches had a previous immunization history. As a result, we speculated that the positive CDCXM but negative FCXM results were due to the washing procedures in the FCXM disturbing antigen-antibody complexes. We suggest at least two different methods to be performed for crossmatch tests before kidney transplantation. CDCXM detects immunoglobulin G1 (IgG1) and IgG3, which are critical for rejection. FCXM is able to detect all IgG subgroups because of its high sensivity. As a result we suggest that both CDCXM and FCXM are preferrable strategies to detect DSAs.