A two-arm prospective trial evaluating the ability of EBV PCR to diagnose and monitor posttransplant lymphoproliferative disorder

Abstract

8057 Background: EBV PCR is known to be useful in the management of patients with PTLD. However, the optimal DNA target, relative importance of peripheral blood intracellular versus free plasma EBV, and baseline profile of these EBV PCR variations in a transplant population remains unclear. This study explored these issues as well as assessed the utility of a 6 assay EBV PCR panel in the management of patients with suspected PTLD. Methods: A prospective 2-arm study was performed. Arm A consisted of 31 patients who underwent lung transplantation. Arm B consisted of 35 patients evaluated for possible PTLD. All patients underwent an initial evaluation with EBV PCR and EBV VCA antibody titer. Arm B patients were evaluated for PTLD with CT scans and biopsies of lesions. All patients in Arm A and those in Arm B with documented PTLD were then followed. For the EBV PCR panel, peripheral blood was separated into plasma and whole blood cells and then DNA was purified. Real time EBV PCR was then performed on both samples using primer sets against LMP, EBER and EBNA. Results: No patients on control Arm A developed PTLD. Seventeen (49%) patients on Arm B were found to have PTLD. Thirteen of 17 (76%) had EBV(+) PTLD. Eighteen Arm B patients were given non-PTLD diagnoses. Of 62 patients evaluable for EBV antibody titers, 60 (97%) had IgG for EBV VCA. In Arm A, only 1/31 (3%) patients developed a transient positive low level plasma EBV load. Fourteen of 31 (42%) had detectable low-level intracellular EBV. In patients with EBV(+) PTLD, 11/13 had EBV in plasma and intracellular samples, 1 had intracellular EBV only and 1 patient with isolated CNS PTLD had a negative EBV panel. The EBV PCR panel had high sensitivity (92%) and specificity (67%) for diagnosing EBV(+) PTLD. Comparing the individual PCR assays, whole blood EBER had the best sensitivity (92%) and plasma EBNA & EBER had the best specificity (100%). The EBV PCR panel tracked patient's clinical course well (p=0.06) as they proceeded through treatment. EBV plasma (p=<0.01) and whole blood (p=0.04) copy numbers by EBNA PCR inversely correlated with EBV VCA IgG titers. Conclusion: Peripheral blood EBV PCR is useful in the diagnosis and monitoring of patients with EBV(+) PTLD. No significant financial relationships to disclose.