Early BK polyomavirus (BKV) reactivation in donor kidney is a risk factor for development of BKV-associated nephropathy.

The pathogenesis of BK polyomavirus (BKV) infection and associated nephropathy in renal transplant recipients is not clearly understood. To gain insight, urine and plasma samples were collected from 112 renal transplant recipients before and after transplantation and tested for the presence of BKV by polymerase chain reaction. Detection of BKV infection very early (ie, 5 days) after transplantation was identified as a risk factor for subsequent BKV viremia and BKV-associated nephropathy. Phylogenetic analysis of VP1 sequences with corresponding ethnicity data suggests that reactivation was of donor origin. Thus, early testing of urine samples from renal transplant recipients may identify those at risk for BKV-associated nephropathy.