Reducing the risk of viral infection in renal transplantation.

Viruses are under constant surveillance by the immune system. With the introduction of more potent immunosuppressive regimens in transplantation, the increased risk of infectious diseases accompanies the decreased risk of acute rejection. Is the overall burden of immunosuppression the prime consideration or do the various immunosuppressive agents contribute individual risks? Do some immunosuppressive agents actually protect against viral disease? Cytomegalovirus (CMV) was initially a significant complication of transplantation, but the incidence of severe CMV disease has decreased with the identification of high-risk groups and the introduction of screening and prophylactic strategies to control reactivation and de novo infection. Antiviral agents with specificity against CMV have been developed; however, CMV has developed resistance to antiviral agents, causing concern. BK polyomavirus is an emerging threat to renal transplantation, as BK nephropathy can cause significant graft loss, often within the first few years of the transplant. Return to dialysis carries increased morbidity and mortality and reduced quality of life. This brief overview examines the clinical literature regarding these viruses and discusses the potential for manipulating intracellular signaling pathways using specific immunosuppressive agents to inhibit viral reactivation and replication.