Molecular Methods for Detecting Epstein-Barr Virus (Part III): EBV Viral Load by Competitive Polymerase Chain Reaction

Epstein-Barr virus (EBV) viral load testing is rapidly gaining acceptance in the diagnosis and monitoring of patients with EBV-related neoplasia, including transplant recipients, autoimmune deficiency syndrome (AIDS) patients with brain lymphoma, and patients with nasopharyngeal carcinoma. In transplant recipients, several studies have shown that EBV viral load in blood is a useful marker of EBV-driven posttransplant lymphoproliferative disease (PTLD), both in terms of predicting disease and in monitoring efficacy of therapy (1 –4 ). In AIDS patients, high EBV viral load in cerebrospinal fluid (CSF) is so characteristic of brain lymphoma that the assay has been touted as sufficient for making that diagnosis without the need for brain biopsy, assuming that there is also clinical and radiographic support for the diagnosis (5 ). In nasopharyngeal carcinoma patients, a recent study showed that plasma EBV viral load is nearly always elevated, and the degree of elevation is higher in those with distant metastases (6 ). Additional studies are needed to more completely define the utility of EBV viral load measurement in monitoring residual disease following therapy, and to evaluate clinical utility in other EB V-associated diseases.