Unrelated versus related living-donor kidney transplantation is associated with higher acute rejection rate but similar graft survival Running title: Outcomes in living-donor kidney transplantation

Abstract

Kidney transplantation (KT) from living donors has been shown to have multiple benefits compared with that from deceased donors. We sought to compare significant graft outcomes, namely acute rejection (AR), graft function, and survival, between transplant recipients who received a kidney from a living-related donor (LRD) and from a living unrelated donor (LURD). Our cohort comprised 198 donor and recipient pairs undergoing living-donor KT at our center over 10 years. LRD recipients were compared with LURD recipients according to demographic and clinical characteristics, transplant variables (including immunosuppression), graft function, survival, and AR rate. The estimated glomerular filtration rate (eGFR) was similar in both groups over the follow-up time, of 60-65 mL/min (p<0.05 over a 10-year period). Censored graft survival was similar between LRD and LURD recipients (96.9% vs. 98.0% at 5 years and 87.8% vs. 79.4% at 10 years, respectively; p=0.837). LURD recipients had a higher incidence of AR, although LURD recipient status was not an independent risk factor for AR. Multivariate analysis showed that human leukocyte antigen (HLA) -DR mismatch (MM) was an independent predictor of AR (hazard ratio [HR] 2.256, p<0.05). HLA-A and HLA-B MM did not affect the AR HR between the groups. Graft function and censored-death survival rates were similar between the LURD and LRD KT recipients. HLA-DR MM was an independent risk factor for AR.