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.