Viral infections are an important complication of transplantation. Immunosuppressive therapy interferes with T cell immunity resulting in a high incidence of viral infection. Newer agents, such as mycophenolate mofetil (MMF) and sirolimus, have been associated with an increased risk of herpes virus infection. The introduction of these more potent immunosuppressive agents over the past decade correlates with an increase in the rate of hospitalizations of transplant patients with infections. This prospective study will determine the role of sub-clinical herpes virus infections in the development of complications such as chronic allograft nephropathy (CAN) and Post Transplant Lymphoproliferative Disease (PTLD). By focusing on treatable herpes virus infections, these studies have the potential to identify therapeutic strategies that can be used to diminish the burden of graft loss from CAN, significantly improving renal allograft survival and quality of life in transplant patients. Future specific interventions to test the hypothesis of a direct causal relationship between sub-clinical herpes virus infection and CAN may include the use of anti-viral therapy in response to sub-clinical infection of the renal allograft and/or peripheral blood.

Inclusion Criteria:

• Age from birth to 21 years
• All solid organ transplant recipients receiving their care at Seattle Children's Hospital
• Signed consent, and when age appropriate, signed assent

Exclusion Criteria:

• Lack of consent

Solid organ transplant recipients receiving their care at Seattle Children's Hospital