BKV QPCR detection and infection monitoring in renal transplant recipients.

BKV associated nephropathy (BKVAN) is a cause of renal dysfunction and loss of the graft in transplants. Viral primary infection is usually inapparent and then BKV establishes latency in kidneys. Reactivation occurs in immunocompromised conditions in renal transplant recipients who can develop a subclinical nephritis and eventually a BKV-associated interstitial nephritis or a BKVAN. In this study, we searched for BKV copies in urine and plasma of renal transplants by quantitative assay (QPCR). Results showed that in several patients clearance of viremia is associated with persistent viruria, suggesting that both specimens are necessary to correctly monitor a BKVAN.