Long-term outcomes of ABO-incompatible kidney transplantation in Argentina: A 10-years single-center experience

Abstract

Introduction: ABO-incompatible (ABOi) kidney transplantation is a feasible option for patients without ABO-compatible (ABOc) living donors. However, its impact on rejection rates and long-term outcomes remains debated. This study aims to compare rejection incidence, graft survival, and patient outcomes between ABOi and ABOc kidney transplant recipients.

Methods: We conducted a retrospective, observational, analytical cohort study at the Hospital Privado Universitario de Córdoba, including all ABOi living donor kidney transplants performed between July 2014 and August 2024. For each ABOi recipient, an ABOc counterpart was matched based on age (±5 years), transplant date (±1 year), and sex (when possible). Patients were followed for up to 10 years post-transplant. Immunosuppressive protocols and infectious prophylaxis followed institutional guidelines.

Results: Of 217 living donor kidney transplants, 33 (15.2 %) were ABOi. No significant differences were found between ABOi and ABOc groups in demographic or clinical baseline characteristics, except for donor age (p = 0.026). There were no differences in graft function, major complications, graft loss, or mortality between groups. Acute rejection occurred in 11 ABOi patients (9 humoral, 2 cellular) and 10 ABOc patients (5 humoral, 4 cellular, 1 mixed), with no significant differences. The 10-year overall patient survival was 82.8 % for ABOi and 83.7 % for ABOc, while death-censored graft survival was 96.4 % and 91.7 %, respectively. The non-use of thymoglobulin was the only independent predictor of rejection (aOR = 5.44; 95 % CI = 1.16-25.5; p = 0.031).

Conclusion: ABOi kidney transplantation demonstrates comparable long-term outcomes to ABOc transplantation. It is a viable and safe alternative for patients lacking ABO-compatible living donors.

Keywords: ABO blood-group system; Graft rejection; Graft survival; Immunosuppressive agents; Incompatible blood transfusion; Kidney transplantation; Patient survival.