Clinical application of Epstein-Barr virus DNA loads in Epstein-Barr virus-associated diseases: A cohort study.

OBJECTIVES: This study evaluated the diagnostic value of Epstein-Barr virus (EBV) DNA load in blood samples of patients with EBV-associated diseases, and proposed a strategy for the interpretation of positive EBV DNA results. METHODS: Derivation and validation cohorts were established to evaluate the clinical significance of EBV DNA loads in the peripheral blood mononuclear cells (PBMCs) and plasma from EBV-infected patients. EBV DNA loads were compared and receiver operating characteristic curves were employed to assess the optimal cutoff values of EBV DNA for identification of EBV-associated diseases. RESULTS: The derivation and validation cohorts comprised 135 and 71 subjects, respectively. EBV DNA loads in the PBMCs of the EBV-associated diseases group was significantly higher than that of the EBV non-associated diseases group (5.8 × 104 vs 7.8 × 103 copies/106 cells, P<0.0001). The diagnostic cut-off value of viral load in PBMCs for EBV-associated diseases was determined to be 1.6 × 104 copies/106 cells. The combined EBV DNA load cutoff in PBMCs and positive EBV DNA qualitative detection in plasma (>500 copies/mL) allowed for the differentiation of EBV-associated and non-associated diseases; the sensitivity and specificity were 80.6 and 96.8%, respectively. CONCLUSIONS: The strategy of combining EBV DNA loads in PBMCs and plasma will potentially help identify EBV-associated diseases.