Predictive value of Epstein-Barr virus genome copy number and BZLF1 expression in blood lymphocytes of transplant recipients at risk for lymphoproliferative disease

Epstein-Barr virus (EBV) genome numbers and RNA transcripts from the immedi ate-early EBV gene BZLF1 were monitored by means of polymerase chain reacti on in peripheral blood lymphocytes (PBLs) of 44 children who received liver transplants. The 2 tests were compared, using several parameters to assess their value as predictors of posttransplantation lymphoproliferative disea se (PTLD), All patients were infected with EBV. BZLF1 mRNA was positive in 70% of patients, with highest expression in those with largest virus load, Four patients developed PTLD that could not be unequivocally diagnosed by a ny of the parameters considered alone, Sensitivity of EBV genome number (gr eater than or equal to 40,000 EBV copies/10(5) PBLs) and BZLF1 mRNA (BZLF1 : glyceraldehyde-3-phosphate-dehydrogenase ratio greater than or equal to 0 .5) was 100%. Specificity of each of the 2 tests alone (98% and 58%, respec tively) improved (to 100% and 83%, respectively) when measurement of serum IgG level was included. Because decreased virus load, but not BZLF1 mRNA ex pression, accurately predicted favorable responses of PTLD to therapy, moni toring of EBV genome numbers alone appears sufficient in children with live r transplants.