Activation and adoptive transfer of Epstein-Barr virus-specific cytotoxic T cells in solid organ transplant patients with posttransplant lymphoproliferative disease

The treatment of Epstein-Barr virus (EBV)associated lymphoproliferative dis ease (PTLD) in EBV seronegative solid organ transplant recipients who acqui re their EBV infection after engraftment poses a considerable challenge bec ause of underlying immunosuppression that inhibits the virus-specific cytot oxic T cell (CTL) response in vivo. We have developed a protocol for activa ting autologous EBV-specific CTL lines from these patients and show their p otential use for immunotherapy against PTLD in solid organ transplant patie nts. Peripheral blood mononuclear cells from a panel of solid organ transpl ant recipients with and without active PTLD were used to assess EBV-specifi c memory CTL responses. The activation protocol involved cocultivation of p eripheral blood mononuclear cells with an autologous lymphoblastoid cell li ne under conditions that favored expansion of virus-specific CTL and hinder ed the proliferation of allospecific T cells. These CTL consistently showed (i) strong EBV-specificity, including reactivity through defined epitopes in spite of concurrent immunosuppressive therapy, and (ii) no alloreactivit y toward donor alloantigens. More importantly, adoptive transfer of these a utologous CTLs into a single patient with active PTLD was coincident with a very significant regression of the PTLD, These results demonstrate that a potent EBV-specific memory response can be expanded from solid organ recipi ents who have acquired their primary EBV infection under high levels of imm unosuppressive therapy and that these T cells may have therapeutic potentia l against PTLD.