Pre-transplant shedding of BK virus in urine is unrelated to post-transplant viruria and viremia in kidney transplant recipients

BK virus-(BKV) associated nephropathy (BKVN) is a major cause of allograft injury in kidney transplant recipients. In such patients, subclinical reactivation of latent BKV infection can occur in the pre-transplant period. The purpose of this study was to determine whether urinary BKV shedding in the immediate pre-transplant period is associated with a higher incidence of viruria and viremia during the first year after kidney transplantation. We examined urine samples from 34 kidney transplant recipients, using real-time quantitative polymerase chain reaction to detect BKV. Urine samples were obtained in the immediate pre-transplant period and during the first year after transplant on a monthly basis. If BKV viruria was detected, blood samples were collected and screened for BKV viremia. In the immediate pre-transplant period, we detected BKV viruria in 11 (32.3%) of the 34 recipients. During the first year after transplantation, we detected BKV viruria in all 34 patients and viremia in eight (23.5%). We found no correlation between pre-transplant viruria and post-transplant viruria or viremia (p = 0.2). Although reactivation of latent BKV infection in the pre-transplant period is fairly common among kidney transplant recipients, it is not a risk factor for post-transplant BKV viruria or viremia.