Epstein-Barr virus-positive diffuse large B-cell lymphoma features disrupted antigen capture/presentation and hijacked T-cell suppression.

: B cells can function as antigen-presenting cells by presenting antigens captured by the B-cell receptor (BCR) on Class II Major Histocompatibility Complex (MHC II) to T cells. In addition, B-cells can also maintain immune homeostasis by expressing PD-L1 and suppressing T-cell activity. Epstein-Barr virus (EBV) infection can disrupt B-cell function and lead to B cell malignancies, including diffuse large B-cell lymphoma (DLBCL). Here we show that EBV-positive DLBCL (EBV+ DLBCL) has decreased expression of BCR and MHC II, but over-expressed PD-L1, which may lead to immune evasion. : An EBV+ DLBCL cohort (n = 30) and an EBV- DLBCL control cohort (n = 83) were established. Immunostaining of PD-L1, MHC II, MHC II Transactivator (CIITA) and pBTK was performed on automated stainer. H-score was used to denote the results of staining of PD-L1 and pBTK. Break apart and deletion of locus was studied by fluorescent hybridization. Surface immunoglobulin mean fluorescent insensitivity (MFI) was detected by flow cytometry to demonstrate the level BCR. : EBV+ DLBCL showed significantly lower expression of CIITA and MHC II compared to EBV- DLBCL. Genetic aberrations involving were also more common in EBV+ DLBCL, with 23% break apart events and 6% deletion events, comparted to 2% break apart and 0% deletion in EBV- DLBCL. In addition to the loss of antigen presentation molecule, the antigen capture receptor, BCR, was also down-regulated in EBV+ DLBCL. Accordingly, BCR signaling was also significantly decreased in EBV+ DLBCL as denoted by the respective pBTK levels. : EBV+ DLBCL shows over expression of the T-cell inhibitory ligand, PD-L1. Antigen capture and presentation system were disrupted, and T-cell inhibitory molecule was hijacked in EBV+ DLBCL, which may contribute to immune escape in this high risk disease. Therapies targeting these aberrations may improve the outcome of patients with EBV+ DLBCL.