Monitoring of Epstein–Barr virus load and antibody in pediatric renal transplant patients

Background: Epstein–Barr virus (EBV) infection can lead to life-threatening post-transplant lymphoproliferative disorder (PTLD). The aim of the present study was to establish EBV monitoring methods to prevent PTLD. Methods: EBV-DNA load was investigated, using real-time polymerase chain reaction (PCR) and anti-EBV antibody titers, in peripheral blood mononuclear cells of 21 renal transplant patients (seven recipients who were EBV-seronegative, R[−]; 14 who were EBV-seropositive, R[+]) before grafting. The mean age at entry and the mean follow-up period was 7.8 years of age (range, 3.3–12.0 years) and 1.8 years (range, 0.4–4.0 years), respectively, in the R(−) group, and 12.5 years of age (range, 3.9–17.7 years) and 3.8 years (range, 0.8–8.2 years) in the R(+) group, respectively. Results: The mean maximum load of the EBV genome was 1071 copies/μg DNA (range, 106–20700 copies/μg DNA) in the R(−) group, and 61 copies/μg DNA (range, <50–552 copies/μg DNA) in the R(+) group. During follow up no patient in the R(+) group had any noticeable symptoms that could be related to EBV, but three recipients in the R(−) group developed EBV-related symptoms including adenoid hypertrophy, cervical lymphadenopathy, and PTLD (B cell lymphoma), in one patient each. In the R(−) group the first leukocyte-associated viremia was detected at 30–180 days, and seroconversion at 43–266 days after transplantation. Conclusions: Viral DNA detection using PCR is a useful tool for EBV surveillance, but the maximum EBV load was not markedly elevated (2474 copies/μg DNA) in a patient with PTLD. Therefore, EBV surveillance using only monitoring of EBV load in peripheral leukocyte may be insufficient. Histology may therefore be necessary to accurately diagnose PTLD.