BK polyomavirus infection in the renal transplant recipient.

Renal transplant recipients continue to have progressive kidney dysfunction and renal graft loss has been attributed to emerging opportunistic infections, specifically BK virus (BKV). BKV is postulated to be selected by the new potent immunosuppressive medications and to be an important factor in graft failure. The prevalence of BKV nephropathy (BKVN) is estimated to be 1% to 10% and renal allograft loss from BKVN has been estimated to occur in up to 50% of affected recipients. With the increasing recognition of BKV infection using PCR assays coupled with the immediate reduction in immunosuppression for BKVN, the incidence of graft failure secondary to BKVN may be decreasing.