Evaluation of lymphocyte crossmatch (CDCXM and Flow XM) test results before kidney transplantation

Purpose: Detection of anti-HLA antibodies is crucial in pre-transplant immunological assessment to evaluate donor-recipient compatibility and prevent hyperacute rejection. This study aimed to evaluate lymphocyte crossmatch (XM) test results performed before kidney transplantation.Materials and methods: Lymphocyte crossmatch tests conducted at the Tissue Typing Laboratory of Pamukkale University Hospital between February 2020 and February 2024 were retrospectively analyzed. CDCXM (Complement-Dependent Cytotoxicity Crossmatch) and flow cytometric crossmatch (FCXM) tests were performed. For CDCXM, T and B lymphocytes were separated and tested individually, with serial dilution and DTT treatment applied. FCXM used anti-CD3 for T lymphocytes, anti-CD19 and anti-IgG for B lymphocytes, analyzed on a 10-color, 3-laser flow cytometer (Navios EX-Beckman Coulter, Inc. USA).Results: A total of 225 CDCXM test results, 105 of which were alive and 120 of which were cadaver, were included in the study. CDCXM T and FCXM T were negative in living donors, while CDCXM B and FCXM B positivity were 4.8% and 2.6%, respectively. CDCXM T and B positivity in cadaveric donors were 3.3% and 7.5%, respectively, and FCXM T and B positivity were 3.3% and 8.8%, respectively.Conclusion: Lymphocyte crossmatch remains a reliable and classical method for pre-transplant immunological evaluation. It effectively detects donor-specific anti-HLA antibodies and contributes to the prevention of hyperacute rejection in kidney transplantation.