Quantification of whole-blood EBV DNA in immunocompetent patients with lymphoma.

Abstract

e18524 Background: Epstein-Barr virus (EBV) is an oncovirus associated with several lymphomas. Quantification of EBV viral loads has been reported as a potential biomarker for EBV+ lymphoma. The goal of our study was to detect whole blood EBV DNA viral load at lymphoma diagnosis and correlate it with expression of EBV-encoded RNA (EBER) in tumor tissue. Methods: Between January to December 2009, 59 immunocompetent patients with a diagnosis of lymphoma were included. Five cc of whole blood were taken at diagnosis to determine EBV viral loads using real-time quantitative PCR. EBV in the tumor cells was evaluated by detecting EBER using a chromogenic in situ hybridization (ISH) technique. Results: From 59 patients, 46 (78%) had diffuse large B-cell lymphoma (DLBCL), 3 (5%) Hodgkin, 3 (5%) NK/T-cell extranodal (NKTCL), 4 (7%) adult T-cell leukemia/lymphoma (ATLL), 1 (2%) peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), 1 (2%) subcutaneous T-cell panniculitis-like lymphoma (SQPL) and 1 (2%) Hydroa-vacciniforme-like lymphoma (HVLL). Twelve cases (20%) showed elevated levels of EBV DNA ranging between 0.25-46,400 copies/ul. Six (50%) were DLBCL, 2 (17%) were NKTCL, 2 (17%) were ATLL, 1 (8%) Hodgkin and 1 (8%) HVLL. Ten cases (83%) expressed EBER in tumor tissue. Eight (80%) were EBER+ within tumor cells and 2 (20%) were positive within the microenvironment. Five (out of 6, 83%) DLBCL cases were positive for EBER. These cases were later defined as EBV+ DLBCL of the elderly (WHO). Two ATLL cases were EBER+ in the microenvironment. Two (out of 3, 66%) NKTL patients had detectable levels of EBV DNA as well as our case of HVLL; these 3 cases were positive for EBER. Conclusions: These results suggest that whole blood EBV DNA quantification correlates with the expression of EBER, detected by ISH, within the tumor tissue and might be of value as a biomarker in patients with EBV+ lymphomas, especially EBV+ DLBCL of the elderly. ATLL expresses EBER within the tumor microenvironment.