Introduction: Epstein-Barr virus (EBV) is associated with clinical symptoms, such as lymphadenopathy, fever, and hepatitis as well as development of EBV+ post-transplant lymphoproliferative disorders (PTLD), which is the most common malignancy in children after transplant; however, there is insufficient evidence of risk factors for EBV DNAemia investigated based on prospectively collected data in pediatric transplantation.

Methods: This prospective, multicenter, study (NCT02182986) enrolled 944 children (≤ 21 years of age). Of these, 872 patients received liver, heart, kidney, intestinal, or multivisceral transplants (LT, HT, KT, and IT, respectively) in seven US centers between 2014 and 2019 (NCT02182986). EBV DNAemia was monitored by collecting blood samples prospectively (n = 4753) at multiple timepoints: enrollment or transplant, every 3 months during the first 2 years, twice yearly thereafter. After patient selection, 470 patients (261 LTs, 97 HTs, 79 KTs, and 33 ITs) were retrospectively analyzed. The clinical variables included sex, age, race, ethnicity, pre-transplant EBV and cytomegalovirus (CMV) serologies, and induction therapy. Cumulative incidence of EBV DNAemia within a year of transplant was compared, with patient death as a competing risk.

Results: The cohort included 265 males and 205 females, and the median age at transplant was 4.1 years (IQR: 1.3–12.7). Uni/multivariable analyses revealed the combination of EBV-seropositive donor and EBV-seronegative recipient (D+R-) vs. D-R+ (sub-hazard ratio: 9.81 [3.05–31.5], P <0.001), D+R- vs. D-R- (7.22 [2.18–23.9], P =0.001), D+R+ vs. D-R+ (6.81 [2.13–21.7], P <0.001), and D+R+ vs. D-R- (5.01 [1.54–16.3], P =0.007) were significant risk factors for EBV DNAemia within a year post-transplant (Fig. 1A). Additionally, LT vs. HT (3.11 [1.54–6.28], P =0.002) and CMV IgG-negative recipient (1.73 [1.05–2.85], P =0.03) were also significant risk factors for EBV DNAemia within a year post-transplant (Fig. 1B, 1C)

Subgroup analyses for each transplanted organ showed that D+R-, D+R+, and CMV-IgG+ in LT, younger age in KT, and CMV-IgG+ in HT were significant risk factors for EBV DNAemia. Focusing on D/R relationship, LT showed a similar impact of D/R relationship on EBV DNAemia to the entire cohort (Fig. 2A). In contrast, KT presented a significantly higher incidence rate of EBV DNAemia in D+R- than in D+R+ (Fig. 2B). HT and IT showed almost similar incidences of EBV DNAemia in all groups except D-R+ and D-R- groups, respectively (Fig. 2C, 2D).

Conclusions: Of note, D+R- as well as D+R+ were risk factors for EBV DNAemia compared to the D- group, suggesting that EBV-seropositive recipients were probably reinfected by genetically different EBV from recipients’ EBV. The fact that D+R+ patients, the most common population of transplant recipients, are more likely to develop EBV DNAemia than recipients of EBV-naïve organs should be emphasized in terms of post-transplant follow-up.