Expansion of EBNA1-specific effector T cells in posttransplantation lymphoproliferative disorders

Abstract

Immunosuppression resulting in impaired Epstein-Barr virus (EBV)-specific T-cell immunity is involved in the pathogenesis of EBV-positive post-transplantation lymphoproliferative disorder (EBV ؉ PTLD).Restoration of EBV-specific T-cell immunity by adoptive immunotherapy can induce remission. EBV-nuclear antigen-1 (EBNA1) is unique in being expressed in all cases of EBV ؉ PTLD. Recent data demonstrate that EBNA1 is not immunologically silent and can be exploited as a T-cell target. There are no data on EBNA1-specific T cells in PTLD. EBNA1-specific T cells capable of proliferation, interferon-␥ release, and CD107a/b degranulation were assayed in 14 EBV ؉ PTLD diagnostic blood samples and 19 healthy controls. EBNA1-specific CD4 ؉ T cells predominated and were expanded in 10 of 14 patients and 19 of 19 controls. Although human leukocyte antigen class I alleles influenced the magnitude of the response, EBNA1-specific CD8 ؉ effector T cells were successfully generated in 9 of 14 EBV ؉ PTLD patients and 16 of 19 controls. The majority of PTLD patients had a polymorphism in an EBNA1 epitope, and T-cell recognition was greatly enhanced when EBNA1 peptides derived from the polymorphic epitope were used. These results indicate that EBNA1-specific T cells should be included in adoptive immunotherapy for PTLD. Furthermore, expansion protocols should use antigenic sequences from relevant EBV strains. (Blood. 2010;116(13):2245-2252) IntroductionPost-transplantation lymphoproliferative disorder (PTLD) encompasses the spectrum of lymphoproliferative diseases that arise as a complication of organ transplantation. The incidence of PTLD varies depending on the type of organ transplanted (up to 30% for lung and small bowel transplantations vs 1%-5% for renal, cardiac, and liver transplantations) and the degree of immunosuppression. 1 Management remains suboptimal, relapses are frequent, and treatment-related mortality is high. 2 The rise in solid-organ transplantation, including high-risk solid-organ transplantation requiring more intense immunosuppression, coupled with improvements in long-term survival will probably result in a rise in the incidence of PTLD.The majority of PTLD cases (50%-80%) are positive for Epstein-Barr virus (EBV ϩ PTLD). EBV is an oncogenic ␥-herpes virus that infects more than 90% of adults worldwide. After primary infection, the virus persists for life within B cells. This asymptomatic state is, in part, maintained by T-cell-mediated immune control. 3 EBV ϩ PTLD arises partly as an iatrogenic consequence of immunosuppression resulting in the loss of antiviral immunity. 4 However, reduction of immunosuppression fails to induce a response in the majority of cases, suggesting that other mechanisms, including intratumoral immunosuppression, could operate in established PTLD. The expression of EBVlatent antigens in EBV ϩ PTLD provides an ideal target for in vitro-generated tumor antigen-specific T cells in an environment free from the constraints of ongoing iatrogenic and/or lymphomamediated immunosuppression. ...

Adenovirus-Based Vaccines against Rhesus Lymphocryptovirus EBNA-1 Induce Expansion of Specific CD8 + and CD4 + T Cells in Persistently Infected Rhesus Macaques

“…While adoptive transfer of ex vivo-expanded EBV-specific T cells has resulted in sustained clinical responses in some patients (56), adoptive immunotherapy is costly, requires access to highly specialized health care facilities, and is therefore an impractical solution for the thousands of patients diagnosed annually with EBVassociated diseases. Another study showed that EBNA-1-specific CD8 ϩ T cells could be isolated from healthy human adults as well as from patients with posttransplantation lymphoproliferative disease (57). These results are in agreement with our studies, which showed not only that rhLCV-infected rhesus macaques mount an rhEBNA-1-specific CD8 ϩ T cell response upon natural infection but also that these CD8 ϩ T cells can be expanded in vivo upon vaccination.…”

The impact of HLA class I and EBV latency-II antigen-specific CD8+ T cells on the pathogenesis of EBV+ Hodgkin lymphoma

“…Indeed, low‐frequency responses can be detected via in‐vitro expansion in patients receiving immunosuppressive therapies 13. Furthermore, up to four different HLA‐A/B molecules can potentially present relevant EBV‐derived epitopes in each individual, adding a confounding layer of complexity to single allele‐based effects.…”

Immune defence against EBV and EBV-associated disease

“…CD4+ T cells are also potential effectors against such tumours with the description of cytotoxic clones against CD4 epitopes in LMP1 [53,54], LMP2 [53] and EBNA1 [55], the latter with proven activity against T/NK lymphoma cells in vitro. Various methods have been designed to produce effector populations enriched in appropriate specificities, for example by ex vivo selection with EBVspecific pentamers [56] or by in vitro stimulation either with epitope peptides [57,58], with the autologous LCL over-expressing the particular antigen of choice [59], or with an adenovirus encoding EBNA1/LMP1/LMP2 epitope strings [60] or a scrambled EBNA1, LMP1, LMP2 protein sequence [61]. Such chimaeric constructs could also be used to boost relevant antigen-specific responses in the patient by vaccination.…”