BK virus infection following kidney transplantation: an overview of risk factors, screening strategies, and therapeutic interventions.

PURPOSE OF REVIEW: In recipients of kidney transplants, the emergence of BK virus (BKV)-associated clinical syndromes, such as viruria, viremia, and BK nephropathy, coincided with the advent of potent immunosuppressive therapy. There is currently no standardized protocol for the management of BK viruria or viremia, or established BK nephropathy. Suggested risk factors for BKV replication and a literature overview on various treatment strategies for BKV-associated clinical syndromes are presented, followed by the authors' proposed approach for screening, monitoring, and treatment of post-transplant BKV infection. RECENT FINDINGS: BKV infection can occur under all combinations of immunosuppressive therapy. Although both humoral and cellular immunity may be essential, BKV-specific T-cell immunity appears to play a pivotal role in controlling BKV replication. Monitoring BKV-specific immune response might prove useful in guiding therapeutic intervention. The beneficial effects of antiviral agents remain unclear. Development of T-cell or antibody-based vaccines against BKV is a subject of future research. SUMMARY: In the absence of conclusive evidence that any particular immunosuppressive agent has a specific influence over another on BKV infection risk and the unclear benefit of antiviral agents, intensive monitoring of serum BKV using PCR and immunological containment of BKV replication should remain the mainstay of therapy. The routine recommendations of antiviral agents in the treatment of BKV-associated clinical syndromes await results of large prospective randomized trials.