Viral states and immune competence in Epstein–Barr virus-positive diffuse large B-cell lymphoma: conditions for therapeutic targeting

Epstein–Barr virus (EBV)-positive diffuse large B-cell lymphoma (DLBCL) exhibits distinct viral expression, antigen-presentation and immune states that shape therapeutic opportunities. Malignant-cell viral attribution anchors diagnosis, while therapeutic activity depends on the target and mechanism being engaged. This critical narrative review integrates current disease definitions with viral and host dependencies, local immune organization, peripheral antiviral function and treatment evidence. Recent spatial studies identify latent membrane protein 1 (LMP1)-associated myeloid niches and heterogeneous human leukocyte antigen (HLA) expression, including increased HLA expression in LMP1-positive compared with LMP1-negative malignant B cells. Peripheral studies report reduced peptide-pool interferon-γ responses and increased CD4 responses to autologous lymphoblastoid cells, emphasizing that stimulus and responding cell population define the measurement. These observations connect viral state with specific opportunities to improve recognition, effector function and tumor access. Virus-specific T cells require a relevant antigen and a shared restricting HLA allele; surface-antigen redirection uses a different recognition route; checkpoint blockade acts on recoverable immune responses; and induction–antiviral combinations require an induced cell fraction with functional drug activation and additional tumor killing. Small clinical series demonstrate activity in selected settings, while negative comparative findings and posted trial outcomes define the limits of that evidence. Studies with paired tissue and blood sampling, functional perturbation and prospectively specified biomarker-by-treatment analyses can establish which biological measurements improve treatment selection. The resulting research agenda links disease-specific viral and immune biology to measurable therapeutic requirements.