Unveiling Donor-Derived BKPyV DNAemia Through Analysis of Contralateral Kidney Transplant Recipients

Background: BK polyomavirus (BKPyV) infection is of notable concern in kidney transplant recipients, as it can cause BKPyV-associated nephropathy (BKPyVAN). Currently, there is no effective treatment for BKPyV infection, underscoring the need for preventive strategies. There is emerging evidence that donor-derived BKPyV plays a role in the development of BKPyV DNAemia. To further explore this hypothesis, we conducted a retrospective, multi-center cohort study to evaluate the risk of developing BKPyV DNAemia in kidney recipient pairs sharing the same donor. Methods: At the Leiden University Medical Center (LUMC), deceased donor kidney transplant recipients (2011-2021) were identified and classified according to the occurrence of BKPyV DNAemia within the first year post-transplantation. For each recipient, the contralateral kidney recipient from the same donor was identified through national transplant registries. Cox regression was used to assess whether BKPyV DNAemia in the LUMC recipient was associated with an increased risk of BKPyV DNAemia in the contralateral recipient. Results: Among 117 recipient pairs, BKPyV DNAemia was more frequent when the contralateral recipient was affected (28.8% [15/52]), compared with pairs in which the contralateral recipient remained unaffected (10.8% [7/65], p = 0.013). Multivariable Cox regression analysis confirmed this increased risk (HR 4.9, 95% CI: 1.8-13.6; p = 0.002). Conclusions: This study shows a significantly increased risk of BKPyV DNAemia in recipients of deceased donor kidneys when the contralateral kidney recipient develops BKPyV DNAemia. These findings highlight the influence of donor-derived factors in BKPyV transmission in kidney transplantation.