The viral load of Epstein-Barr virus (EBV) DNA in peripheral blood predicts for biological and clinical characteristics in Hodgkin lymphoma

Purpose: The Epstein–Barr virus (EBV) is present in the malignant Hodgkin/Reed–Sternberg (HRS) cells 8 of 20% to 40% cases of Hodgkin lymphoma (HL) in Western countries. We were interested in the detection 9 and quantification of cell-free plasma EBV-DNA as an indicator of biological and clinical characteristics in 10 EBV-associated HL. 11 Experimental Design: EBV was detected in peripheral blood compartments (whole blood, plasma, and 12 Q1 mononuclear cells) at diagnosis by real-time PCR for the EBNA (EB nuclear antigen) region (n ¼ 93) and in 13 Q2 HRS cells by in situ hybridization for EBV-encoded small RNAs (EBER; n ¼ 63). These data were correlated 14 to histological and clinical characteristics, EBV serology, circulating cell-free DNA, and interleukin (IL)-6 15 levels. 16 Results: Detection of EBV-DNA in plasma had a high specificity (90%), but a relatively low sensitivity 17 (65%) to predict for EBV association. The viral load was higher in patients with advanced stage disease, 18 older age in the presence of B-symptoms, and international prognostic score more than 2. The presence of 19 EBV in HRS cells and higher plasma EBV-DNA copy numbers correlated to an increased frequency of 20 tumor-infiltrating CD68þ macrophages in lymph node biopsies. Plasma EBV-DNA load correlated to 21 circulating cell-free DNA and IL-6 levels, and inversely correlated to lymphocyte counts and EBNA1 22 antibody titers. 23 Conclusion: Although the presence of EBV-DNA in peripheral blood cannot be regarded as a surrogate 24 marker for EBER, the plasma EBV-DNA load at HL diagnosis is an indicator of disease activity and 25 biological characteristics associated with negative prognosis. Moreover, the inverse correlation to EBNA1 26 antibody titers and lymphocyte counts may indicate a reduction in immunosurveillance, favoring the 27 expansion of EBV-HRS cells in HL. Clin Cancer Res; 17(9); 1–8. 2011 AACR.