Epidemiology and outcome of chronic high Epstein-Barr viral load carriage in pediatric kidney transplant recipients

INTRODUCTION: The development of Epstein-Barr virus (EBV) infection and post-transplant lymphoproliferative disorder (PTLD) is normally associated with a high EBV viral load in peripheral blood. Observations have previously identified existence of a chronic EBV high load (CHL) carrier state which demonstrated variable outcomes based upon the organ which was transplanted. Data defining the incidence and outcome of CHL in pediatric kidney transplantation (KTx) are not well described. METHODS: The charts of children undergoing isolated KTx at Children’s Hospital of Pittsburgh between January 2000 and December 2014 were retrospectively reviewed. EBV loads in the peripheral blood were routinely measured as part of surveillance protocols at our center. CHL was defined as the presence of high load for >50% of samples for ≥6 months. PTLD was defined histologically using WHO definitions. RESULTS: Of 188 isolated KTx recipients, we identified a total of 16 (8%) children who developed CHL carrier state. No patient developed EBV-driven late onset PTLD. Age at the time of KTx was significantly lower in CHL group (median 3.9 years, interquartile range: IQR 2.9-6.6, p=0.0004). Children in the CHL group were more likely to be EBV seronegative prior to KTx (94%, 15/16), compared to the undetectable viral load (UVL) and low viral load (LVL) groups (55% and 50%, respectively, p