Herpesviruses and polyomaviruses in renal transplantation.

Viral infections remain a significant cause of morbidity and mortality among transplant patients despite recent advances in early detection and treatment. Herpesviruses and polyomaviruses are the most relevant viruses post-transplant as they establish latency in immunocompetent individuals and frequently reactivate in the immunosuppressed transplant recipient. Although we have made significant strides in the early diagnosis and treatment of viral infections in renal transplant recipients over the past five years, many questions remain. Optimization of screening and prophylactic/preemptive protocols, as well as standardization of viral diagnostic testing are still needed. Understanding how viruses modify the host's immune responses, and conversely how variations between hosts' ability to mount an immune response against viruses are important areas of research that might allow for more individualization of immunosuppressive regimens. Other exciting areas of ongoing study include the associations between various HLA loci/mismatches and viral replication/infection, the mechanisms by which certain viruses (i.e., Epstein-Barr virus, human herpes virus 8) are oncogenic, and the development of new therapeutic strategies such as adoptive transfer of antigen-specific T cells to restore immunity and control viral infections.