Background
Two apolipoprotein L1 gene (APOL1) renal-risk variants in donors and African American (AA) recipient race are associated with worse allograft survival in deceased-donor kidney transplantation (DDKT) from AA donors. To detect other factors impacting allograft survival from deceased AA kidney donors, APOL1 renal-risk variants were genotyped in additional AA kidney donors.
Methods
APOL1 genotypes were linked to outcomes in 478 newly analyzed DDKTs in the Scientific Registry of Transplant Recipients. Multivariate analyses accounting for recipient age, sex, race, panel reactive antibody level, HLA match, cold ischemia time, donor age, and expanded-criteria donation were performed. These 478 transplantations and 675 DDKTs from a prior report were jointly analyzed.
Results
Fully-adjusted analyses limited to the new 478 DDKTs replicated shorter renal allograft survival in recipients of APOL1-two-renal-risk-variant kidneys (HR 2.00; p=0.03). Combined analysis of 1153 DDKTs from AA donors revealed donor APOL1 high-risk genotype (HR 2.05; p=3×10−4), older donor age (HR 1.18; p=0.05), and younger recipient age (HR 0.70; p=0.001) adversely impacted allograft survival. Although prolonged allograft survival was seen in many recipients of APOL1-two-renal-risk-variant kidneys, follow-up serum creatinine concentrations were higher than in recipients of zero/one APOL1-renal-risk variant kidneys. A competing risk analysis revealed that APOL1 impacted renal allograft survival, but not recipient survival. Interactions between donor age and APOL1 genotype on renal allograft survival were non-significant.
Conclusions
Shorter renal allograft survival is reproducibly observed after DDKT from APOL1-two-renal-risk-variant donors. Younger recipient age and older donor age have independent adverse effects on renal allograft survival.