Abstract
Introduction: Tacrolimus is metabolized mainly in the liver by the CYP3A enzyme family, with a particularly well-documented role of CYP3A5. CYP3A5 is also expressed in the renal tissue and is present in the transplanted kidney. To date, the association between donor CYP3A5 polymorphisms and transplant outcome remains poorly understood. The aim of this study was to assess the effect of donor CYP3A5 expression on early and long-term transplant outcomes. Methods: A retrospective cohort study including 207 patients who received kidney grafts from 110 deceased donors was conducted at a single Central European Center. Tissue samples from all donors were studied for CYP3A5 single-nucleotide polymorphism (rs776746). Death-censored graft loss within 5-year follow-up, acute rejection occurrence, and kidney function, measured using serum creatinine and MDRD eGFR, were compared between groups of patients with allografts from rs776746 carriers (CYP3A5 expressors) and noncarriers (CYP3A5 nonexpressors). Results: Recipients who received kidneys from CYP3A5 expressors (n = 24) were at significantly higher risk of death-censored graft loss within 5-year follow-up (adjusted HR, 95% CI: 6.82, 2.01–23.12; p = 0.002) and acute rejection within the 1st posttransplant year (adjusted OR, 95% CI: 4.62, 1.67–12.77; p = 0.003) than those who did not (n = 183). The median time to loss of function was 1.93 [IQR; 0.77–3.19] years. Conclusions: Donor CYP3A5 expressor status is associated with worse renal graft survival and a higher risk of acute rejection. Determination of donor CYP3A5 genotype is a potentially useful tool that may improve kidney transplant outcomes.