No abstract

T-cell immunotherapy that takes advantage of Epstein-Barr virus (EBV)-

Adoptive transfer of antigen-specific cytotoxic T lymphocytes (CTLs) offers safe and effective therapy for certain viral infections and could prove useful in the eradication of tumor cells. Whether or not the infused T cells persist for extended periods, retaining their ability to expand in response to antigenic stimulation, is not known. We now report long-term detection of gene-marked Epstein-Barr virus (EBV)-specific CTLs in immunocompromised patients at risk for the development of EBV lymphoproliferative disease. Infusions of CTLs not only restored cellular immune responses against EBV, but also established populations of CTL precursors that could respond to in vivo or ex vivo challenge with the virus for as long as 18 months. Our findings support wider use of antigen-specific CTLs in adoptive immunotherapy.

Epstein-Barr virus (EBV) causes potentially lethal immunoblastic lymphoma in up to 25% of children receiving bone marrow transplants from unrelated or HLA-mismatched donors. Because this complication appears to stem from a deficiency of EBV-specific cytotoxic T cells, we assessed the safety and efficacy of donor-derived polyclonal (CD4+ and CD8+) T-cell lines as immunoprophylaxis and treatment for EBV-related lymphoma. Thirty-nine patients considered to be at high risk for EBV-induced lymphoma each received 2 to 4 intravenous infusions of donor-derived EBV-specific T lymphocytes, after they had received T-cell–depleted bone marrow from HLA-matched unrelated donors (n = 33) or mismatched family members (n = 6). The immunologic effects of this therapy were monitored during and after the infusions. Infused cells were identified by detection of the neo marker gene. EBV-specific T cells bearing theneo marker were identified in all but 1 of the patients. Serial analysis of DNA detected the marker gene for as long as 18 weeks in unmanipulated peripheral blood mononuclear cells and for as long as 38 months in regenerated lines of EBV-specific cytotoxic T cells. Six patients (15.5%) had greatly increased amounts of EBV-DNA on study entry (>2,000 genome copies/106 mononuclear cells), indicating uncontrolled EBV replication, a complication that has had a high correlation with subsequent development of overt lymphoma. All of these patients showed 2 to 4 log decreases in viral DNA levels within 2 to 3 weeks after infusion and none developed lymphoma, confirming the antiviral activity of the donor-derived cells. There were no toxic effects that could be attributed to prophylactic T-cell therapy. Two additional patients who did not receive prophylaxis and developed overt immunoblastic lymphoma responded fully to T-cell infusion. Polyclonal donor-derived T-cell lines specific for EBV proteins can thus be used safely to prevent EBV-related immunoblastic lymphoma after allogeneic marrow transplantation and may also be effective in the treatment of established disease. © 1998 by The American Society of Hematology.