Abstract
Mogamulizumab is a defucosylated humanized anti-CC chemokine receptor type 4 (CCR4) antibody that exerts an anti-tumor immune effect against various tumors through a suppressive effect on regulatory T-cells. We herein report a patient with peripheral T-cell lymphoma who developed Epstein-Barr virus (EBV)-related primary diffuse large B-cell lymphoma of the central nervous system (CNS DLBCL) after mogamulizumab therapy. Our experience should alert physicians to the possibility of the development of EBV-related CNS DLBCL in patients treated for primary lymphoma and suggests that the anti-tumor immune effect of mogamulizumab is ineffective for the prophylaxis of EBV-related lymphomas.