Utility of semiquantitative polymerase chain reaction for Epstein-Barr virus to measure virus load in pediatric organ transplant recipients with and without posttransplant lymphoproliferative disease

We examined the utility of Epstein-Barr virus (EBV) load as a test for the presence of posttransplant lymphoproliferative disease (PTLD). A semiquanti tative (SQ) EBV polymerase chain reaction (PCR) on peripheral blood mononuc lear cells (PBMC) was used to determine virus load. We compared the values from pediatric patients, both with and without PTLD, with those from health y pediatric and adult subjects. The virus loads for asymptomatic healthy su bjects had a range of 0-1 log(10) cells/10(6) PBMCs. Among transplant recip ients (n = 135), the mean virus load (+/- standard deviation) at the time o f diagnosis of PTLD was 3.1 +/- 1.2 log(10) cells/10(6) PBMCs versus a base line value of 1.3 +/- 1.4 log(10) cells/10(6) PBMCs in children without PTL D (P < .0001). A cutoff of <greater than or equal to>3 log(10) cells/10(6) peripheral blood leukocytes resulted in the following values for use of vir us load as a test for PTLD: sensitivity, 69%; specificity, 76%; positive pr edictive value, 28%; and negative predictive value, 95%. We conclude that d etermination of EBV load by use of SQ PCR is more useful in ruling out than in indicating the presence of PTLD.