Adoptive transfer of Epstein-Barr virus (EBV)-specific cytotoxic T lymphocytes (CTLs) is effective prophylaxis and treatment of EBV-positive immunoblastic lymphoma in immunocompromised patients. In 50% of patients with Hodgkin's disease, the tumor cells are EBV antigen-positive and may therefore also be suitable targets for treatment with virus-specific CTLs. However, Hodgkin's disease may produce several inhibitory effects on immune induction and effector function in vivo, which may preclude the generation or effector function of CTLs reactive against EBV viral proteins, including those expressed by the tumor cells. We have investigated whether EBV-specific CTLs could be generated ex vivo from 13 patients with Hodgkin's disease: nine with active relapsed disease and four who were in clinical remission after a first or subsequent relapse. CTL lines were successfully generated from nine of 13 patients (five active disease, four remission). Although these lines had an abnormal pattern of expansion comparable to EBV-specific CTLs generated from normal donors, their phenotype was normal except for reduced expression of the zeta chain of the T-cell receptor (TCR). Their cytotoxicity was also compared to EBV-specific lines generated from normal donors and included activity against LMP2a, one of the three weakly immunogenic viral antigens expressed by Hodgkin's tumor cells. To assess the activity of the CTLs in vivo, they were gene-marked and infused into three patients with multiply relapsed disease. The CTLs persisted for more than 13 weeks postinfusion and retained their potent antiviral effects in vivo, thereby enhancing the patient immune response to EBV. This approach may therefore have value in the treatment of EBV-positive Hodgkin's disease.