Chronic high Epstein-Barr viral load carriage in pediatric liver transplant recipients EBV-associated PTLD is a significant cause of morbidity and mortality after solid organ trans- plantation in children (1–3). The risk of devel- oping EBV-associated PTLD appears to be highest in children who experience primary EBV infection following transplantation (4). The development of PCR assays to measure EBV load in the peripheral blood has had an important impact on the management of trans- plant recipients providing a tool for both sur- veillance for, and diagnosis of, EBV infection and PTLD in these patients (5–8). EBV-associ- ated PTLD in children is usually accompanied by the presence of very high EBV viral loads in the peripheral blood, with the rise in load generally proceeding onset of clinical disease. A similar rise in viral load has been observed in pediatric transplant recipients experiencing asymptomatic primary infection and with symptomatic EBV disease not meeting the definition of PTLD. Following the resolution of primary EBV infection or EBV-associated disease (including PTLD), EBV loads generally fall to low levels. However, the availability to perform serial viral load monitoring has identified a population of children who subsequently develop and maintain very high viral loads over prolonged periods of time (9–11). We have termed this population Green M, Soltys K, Rowe DT, Webber SA, Mazareigos G. Chronic high Epstein-Barr viral load carriage in pediatric liver transplant recipients. Pediatr Transplantation 2009: 13: 319–323. Ó 2008 John Wiley & Sons A/S. Abstract: Development of EBV disease and PTLD is usually accom- panied by the detection of a high EBV load in peripheral blood. However, many children undergoing primary EBV infection following LTx will maintain chronically elevated EBV loads in the absence of clinical symptoms. To better understand this phenomenon, we retro- spectively reviewed the records of children undergoing LTx at our center from 1997 to 2007 to identify chronic high EBV load carriers in this population. A CHL state was defined by the presence of a high load for >50% of samples for greater than or equal to six months following either asymptomatic or complete clinical resolution of EBV disease/ PTLD. A total of 35 CHL carriers were identified. Pretransplant serologies were available for 29 of the 35; 22/29 (76%) were EBV negative prior to LTx; eight of these 22 developed their CHL state at the time of their primary EBV infection. Fourteen of the 35 had EBV dis- ease (n = 7) or PTLD (n = 7) prior to development of the CHL state. Only one of 35 CHL carriers developed PTLD or lymphoma while they were a high load carrier. In all, 23/35 resolved their CHL state without apparent sequelae while 11 children continue to be asymptomatic high load carriers. These data provide important information about the outcome of chronic EBV high load carriage in pediatric liver transplant recipients. Michael Green 1,2 , Kyle Soltys 2 , David T. Rowe 3 , Steven A. Webber 1 and George Mazareigos 2 Departments of 1 Pediatrics, 2 Surgery, School of Medicine, ChildrenÕs Hospital of Pittsburgh, University of Pittsburgh, Pittsburgh, PA, USA, 3 Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA Key words: Epstein-Barr virus – post-transplant lymphoproliferative disorders – liver transplantation Michael Green, Division of Infectious Diseases, ChildrenÕs Hospital of Pittsburgh, 3705 5th Avenue, Pittsburgh, PA 15213, USA Tel.: +1 412 692 7438 Fax: +1 412 692 8499 E-mail: michael.green@chp.edu Accepted for publication 8 January 2008 Abbreviations: CHL, chronic high load carrier; EBV, Ep- stein-Barr virus; LTx, liver transplantation; PBMC, peripheral blood mononuclear cells; PCR, polymerase chain reaction; PTLD, post-transplant lymphoproliferative dis- order; QC-PCR, quantitative-competitive EBV-PCR. Pediatr Transplantation 2009: 13: 319–323 Ó 2008 John Wiley & Sons A/S. Pediatric Transplantation DOI: 10.1111/j.1399-3046.2008.00926.x 319