Incidence and Timing of Epstein-Barr Virus Whole Blood DNAemia in Epstein-Barr Virus-Mismatched Adult and Pediatric Solid Organ Transplant Recipients.

Background: Epstein-Barr virus (EBV) viral load (VL) monitoring is recommended post-transplant for EBV-mismatched (donor EBV seropositive/recipient EBV seronegative) solid organ transplant (SOT) recipients as a component of post-transplant lymphoproliferative disorder (PTLD) prevention, but the optimal frequency and timing of EBV VL monitoring remains unknown.

Methods: In this retrospective cohort study, we investigated the incidence and timing of whole blood EBV DNAemia in EBV-mismatched adult and pediatric SOT recipients, who had EBV VL monitoring as part of a pre-emptive approach to PTLD prevention to optimize monitoring algorithms. We explored associations between donor-acquired EBV DNAemia (DA-EBV), defined as EBV DNAemia within 1 year post-transplant, and donor and recipient characteristics, and determined the proportion who developed PTLD.

Results: We analyzed 257 D⁺/R^- recipients (kidney n = 64, heart n = 75, liver n = 93, lung n = 25); 126/257 (49.0%) developed DA-EBV at a median of 83 days (Q1-Q3: 50-130 days) post-transplant. Incidence of DA-EBV varied by organ and was highest in liver (62.4%) and lowest in heart recipients (28.0%). PTLD was diagnosed in 38/257 (14.8%) EBV-mismatched recipients, 25/162 (15.4%) children, and 13/95 (13.7%) adults. DA-EBV was uncommon in recipients less than 6 months old (3/29, 10.3%) and among recipients less than 12 months with donors less than 12 months (2/29, 6.9%); possible mechanisms of protection other than recipient passive maternal antibody and false-positive donor serostatus are discussed.

Conclusion: Monitoring for DA-EBV should be focused on months 2-6 post-transplant. Less frequent whole blood EBV VL monitoring is likely a safe option in recipients less than 6 months old and recipients 6-12 months old with donors less than 12 months old.