Successful treatment of refractory retroperitoneal Epstein-Barr virus-positive diffuse large B-cell lymphoma with secondary hemophagocytic syndrome by sequential combination regimen of PD-1 blockade and chimeric antigen receptor T cells: a case report

Epstein-Barr virus (EBV) is convincingly contributed to the development of several types of lymphomas such as NK/T cell lymphoma, Burkitt lymphoma, plasmablastic lymphoma, and diffuse large B cell lymphoma (DLBCL). Herein, we reported an atypical case of EBV-positive DLBCL in an immunocompetent young male patient who presented with epistaxis due to hypergammaglobulinemia. 2-Deoxy-2-[fluorine-8] fluoro-D-glucose PET/computed tomography showed multiple highly metabolic retroperitoneal tissue masses with the involvement of bilateral adrenal gland. Ultrasonography-guided biopsy revealed a significant number of lymphocytes and plasma-like cells that are immunopositive for plasma-cell markers and partly positive for pan-B cell markers. The Ki-67 proliferation index was 20%. The extensive distribution of EBV-encoded small RNAs was confirmed by in-situ hybridization. Due to atypical/overlapping pathological characteristics, it was initially misdiagnosed as extramedullary plasmacytoma and treated with two cycles of bortezomib, lenalidomide, and dexamethasone. Disease progression occurred and pathology consultation for the retroperitoneal biopsies modified the diagnosis to EBV-positive DLBCL with plasma cell differentiation. The treatment was adjusted to etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, rituximab, and lenalidomide (R2-EPOCH), but no response was observed after three cycles of treatment and he developed hemophagocytic syndrome during treatment. A monotherapy of anti-programmed cell death-1 (PD-1) treatment with tiririzumab was administered, successfully controlling hemophagocytic syndrome and EBV infection. The response assessment was partial for EBV-positive DLBCL, subsequent anti-CD19 chimeric antigen receptor-T (CAR-T) cell therapy resulted in complete remission including lumps, immunoglobulins, and negative EBV-DNA 1.5 months later. The present case study proved the possibility of PD-1 blockade in controlling EBV infection and associated hemophagocytic syndrome and offered an example of the combination of CAR-T therapy and PD-1 blockade for refractory EBV-positive DLBCL in clinic.