Renal Transplantation in Relation to Positive T-cell Flow Cytometric Crossmatch: A Retrospective Study

Human leukocyte antigen antibodies play a significant role in kidney transplant rejection at all stages. Cross-matching and human leukocyte antigen antibody testing, especially in donor-specific antibody (DSA)-positive cases, are essential for reducing the risk of antibody-mediated rejection. Despite increasing numbers of DSA-positive transplants with desensitization therapy, guidelines for assessing transplant suitability and therapy selection remain undefined. This study retrospectively evaluated 12-month outcomes in patients with kidney transplants and positive flow cytometric crossmatch-T (FCXM-T) results.

This study analyzed 200 patients who received kidney transplants at Toranomon Hospital Renal Center between January 2015 and January 2022. Of these, 161 living-donor transplants were selected. The patients were divided into FCXM-T-positive and FCXM-T-negative groups. Regardless of ABO incompatibility, antithymocyte globulin, and rituximab or intravenous immunoglobulin were administered in FCXM-T-positive and DSA-positive cases, whereas rituximab or intravenous immunoglobulin was administered in FCXM-T-positive and DSA-negative cases. Serum creatinine and proteinuria levels were compared 12 months postoperatively using overlap weighting to balance the background factors. FCXM-T-positive cases were further assessed for new DSA development and desensitization effects.

After overlap weighting, creatinine levels (1.33 mg/dL vs 1.38 mg/dL, P = .17) and proteinuria positivity (24% vs 30%, P = .93) did not differ between the FCXM-T-positive and FCXM-T-negative groups at 12 months. The appearance of new DSA was also similar between the groups, suggesting comparable short-term outcomes with appropriate desensitization therapy.

Preoperative desensitization, including antithymocyte globulin, may enable safe kidney transplantation in FCXM-T-positive patients, yielding outcomes comparable to those of low-risk patients. Further long-term studies are required to confirm these findings.