Viral Monitoring in Composite Tissue Transplantation

Marshall Lyon, Emory Transplant Center, Atlanta, GA, USA.

Objectives:

1. Understand which viruses are important in transplantation
2. Learn about current monitoring techniques for viral infections
3. Learn how to screen recipients for latent viral infections and apply relevant monitoring techniques to avoid viral diseases

Viral infections are the most common infections after solid organ transplantation. Current solid organ transplant guidelines recommend screening potential donors and recipients for several viruses, most prominent among these are the human herpes viruses, including cytomegalovirus (CMV) and Epstein-Barr virus (EBV). While not specifically thought of as composite tissues, most organs have several tissue types within them. Therefore the research conducted in traditional organ transplantation can be used to extrapolate to more traditional composite tissue transplantation. Patients who are seronegative and receive organs or tissue from seropositive donors have the highest risk for developing disease. Many organ transplant programs employ prophylaxis as a means of preventing disease. However, active monitoring for viruses and treating at the earliest detection of active viral replication is just as effective at preventing disease caused by these viruses. In some organs the viral monitoring approach is favored because of associated toxicity with prophylactic antiviral agents. Of the laboratory assays currently available for viral monitoring, polymerase chain reaction (PCR) offers the most promise for monitoring. Studies comparing PCR to antigen detection have found that PCR offers increased time between detection and development of disease. In order to be considered an effective screening test (monitoring), and assay must meet three criteria: detection of a marker prior to the development of disease, there is an effective intervention, and intervention early in the disease course alters the outcome of the disease. Of currently available tests, only those for CMV and EBV satisfy all of these criteria and should likely be used for at risk patients.

Recommended reading:

Fisher SA, Avery RK. Screening of donor and recipient prior to solid organ transplantation. Am J Transplantation 2009;9:S7-S18.

Humar A, Snydman D. Cytomegalovirus in solid organ transplant recipients. Am J Transplantation 2009:9:S78-S86.