High levels of Epstein-Barr virus DNA in blood of solid-organ transplant recipients and their value in predicting posttransplant lymphoproliferative disorders.

Epstein-Barr virus (EBV) DNA was quantitated in peripheral blood mononuclear cells (PBMC) from 25 healthy subjects, 105 asymptomatic solid-organ transplant (SOT) recipients, and 15 SOT recipients with symptomatic EBV infections by using a newly developed quantitative-PCR technique. Patients with symptomatic EBV infections had significantly higher (P < 0.001) median EBV DNA levels than asymptomatic SOT recipients and immunocompetent individuals. In SOT recipients, the positive predictive value of EBV DNA levels of >1, 000 genome equivalents (GE)/0.5 microg of total PBMC DNA was 64.7% for symptomatic EBV infection, while the negative predictive value was 96.1%. In 19 of 32 (59.3%) asymptomatic SOT recipients, EBV DNA levels were consistently below 1,000 GE for as long as 18 months, while 10 of 32 (31.2%) patients had 1,000 to 5,000 EBV GE at least once during follow-up. In a minority of patients (3 of 32; 9.3%), >/=5,000 GE could be detected at least once during follow-up. Reduction of immunosuppressive treatment decreased EBV DNA levels by >/=1 log(10) unit in patients with symptomatic EBV infections. Quantification of EBV DNA is valuable for the diagnosis and monitoring of symptomatic EBV infections in SOT recipients.