Presence of EBV antigens detected by a sensitive method in pediatric and adult Diffuse Large B-cell lymphomas.

In 2017, the World Health Organization (WHO) confirmed a new entity, Epstein Barr virus (EBV) + Diffuse large B cell lymphoma (DLBCL), not otherwise specified (NOS). Traces of EBV transcripts were described in lymphomas, including DLBCL, that were diagnosed as EBV negative by conventional methods. The aim of this study was to detect viral genome by qPCR, as well as LMP1 and EBNA2 transcripts, with a more sensitive method in DLBCL cases from Argentina. Fourteen cases originally considered as EBV negative expressed LMP1 and/or EBNA2 transcripts. In addition, LMP1 and/or EBNA2 transcripts were also observed in bystander cells. However, EBERs+ cells cases by conventional ISH showed higher numbers of cells with LMP1 transcripts and LMP1 protein. In the cases that were EBERS- in tumor cells but with expression of LMP1 and/or EBNA2 transcripts, the viral load was below the limit of detection. This study provides further evidence that EBV could be detected in tumor cells by more sensitive methods. However, higher expression of the most important oncogenic protein, LMP1, as well as increased viral load, are only observed in cases with EBERs+ cells by conventional ISH, suggesting that traces of EBV might not display a key role in DLBCL pathogenesis.

PD-1 and LAG-3 expression in EBV-associated pediatric Hodgkin lymphoma has influence on survival.

In pediatric Hodgkin lymphoma (HL), the inability of the cytotoxic microenvironment induced by EBV presence to eliminate tumor cells could reflect the fact that the virus might be able to induce the expression of exhaustion markers to evade an immune response. Therefore, the expression of exhaustion markers in pediatric EBV-associated HL was evaluated. A balance between cytotoxic GrB and Th1 Tbet markers with regulatory Foxp3 was proved in EBV+ cases. In addition, exclusively in EBV-associated cHL, a correlation between PD-1 and LAG-3 expression was observed. Furthermore, those cases also displayed a trend to worse survival when they expressed LAG-3 and inferior event-free survival when both PD-1 and LAG-3 molecules were present. Therefore, even though a cytotoxic and inflammatory environment was supposed to be triggered by EBV presence in pediatric cHL, it seems that the virus may also induce the synergic effect of inhibitory molecules LAG-3 and PD-1 in this series. These observations may reflect the fact that the permissive and exhausted immune microenvironment succeeds to induce lymphomagenesis.