Infusions of Epstein-Barr virus-specific cytotoxic T lymphocytes as post-remission therapy in high-risk post-transplant lymphoproliferative disorder patients: report of two cases.

Conventional therapeutic approaches to post-transplant lymphoproliferative disorder (PTLD) occurring after solid-organ transplantation have shown only limited success in achieving durable response. Key factors driving the pathogenesis of PTLD include Epstein-Barr virus (EBV) reactivation and impaired immune surveillance due to prolonged immune suppression. Thus, EBV-specific cytotoxic T lymphocytes (EBV-CTLs) have emerged as an alternative therapeutic approach for the treatment of EBV-associated PTLD by enhancing EBV-specific immunity. We evaluated the safety and efficacy of EBV latent membrane proteins (LMP)-1- and 2-specific CTLs in two PTLD patients at high risk for relapse. Following diagnosis, patients were initially treated with a combination of chemotherapy and/or radiotherapy. Patients then received a total of eight doses of 2 × 10 EBV-CTLs/m. Following initial therapy, both patients achieved complete remission confirmed by FDG-PET/CT imaging. Post-remission therapy using adoptive transfer of EBV-CTLs was safe without immediate or late toxicities. Infusion of EBV-CTLs led to an overall reduction in plasma EBV levels in the peripheral blood, which was associated with long-term remission of both patients during a follow-up of more than 65 months. Further prospective studies with larger number of patients will be needed to confirm the role of EBV-CTLs as post-remission therapy in high-risk PTLD.