The Use of Autologous LMP2-Specific Cytotoxic T Lymphocytes (CTL) for the Treatment of Relapsed EBV-Positive Hodgkin Disease and Non-Hodgkin Lymphoma.

Abstract

EBV-associated Hodgkin's Disease (HD) and some non-Hodgkins lymphoma (NHL) show type II latency expressing the subdominant EBV antigens EBNA1, LMP1 and LMP2, which may serve as targets for immunotherapy approaches. In previous studies, we used polyclonal EBV-specific CTL in patients with relapsed EBV +ve HD and saw 2 complete and 1 partial response in 11 patients. Analyses of EBV-CTL lines showed that small populations of T cells reactive against the tumor-associated antigen LMP2 were present in the majority of the infused lines, with some expansion in the peripheral blood following infusion. We therefore hypothesized that CTL specifically targeting LMP2 might have greater efficacy in these patients. LMP2-CTL were generated from 14 patients using Dendritic Cells for initial stimulations then Lymphoblastoid Cell Lines (LCL) both of which had been genetically modified to overexpress LMP2 by transduction with an Ad5f35LMP2 vector. Polyclonal LMP2-CTL lines recognized 1–7 (median 2) LMP2 epitopes, as determined using pentamers and overlapping LMP2 peptide pools in ELISPOT assays. A mean of 22.8% (5–42.1%) of CD8+ T cells bound HLA-restricted LMP2 pentamers, compared to a mean of 0.11% (0.01–0.24%) of LMP2-pentamer positive CD8+ T cells found in CTL generated with genetically unmodified LCL from the same patients. So far, 11 patients have been treated on this dose escalation study - 6 patients have been treated on dose level (DL)1 (2 doses of CTL at 2x107/m2/dose given 2 wks apart in the outpatient clinic), 4 patients on DL2 (2x107/m2 and 1x108/m2) and 1 patient on DL3 (1x108/m2 and 2x108/m2). No immediate toxicity was observed. After CTL infusion, an increase in the frequency of EBV +/- LMP2-specific T cells could be detected in the blood in 8/10 evaluated patients (range 2–17.6 fold). Five of 6 patients who received LMP2-CTL as adjuvant therapy post stem cell transplant or chemotherapy remain in remission up to 22mths post LMP2-CTL. 1 patient presented with progressive disease 8 wks post CTL therapy. Five patients had detectable disease at the time of CTL therapy of whom 1 had progressive disease 8 wks post CTL and 4 had clinical responses (1 very good partial response and 3 clinical or radiologic complete responses). One of these 3 patients was evaluated 7 wks after receiving CTLs, which were predominantly CD4+ve (91.6%). Biopsies showed minimal residual NHL cells with increased CD4+ve T cells compared to pre-CTL biopsy specimens. Imaging studies performed 1 wk later were negative for NHL. This patient received 2 extra doses of CTL (given 8 wks apart) and re-evaluations showed CR on PET and CT scans. Two other patients had stable disease 8 wks post LMP2-CTL. Both patients received 2 further doses of LMP2-CTL. One patient is without evidence of disease 12 months post CTL. The other patient had a complete radiological response. This patient had a supraclavicular lymph node resection, which showed selective accumulation of LMP2-tetramer +ve T cells (0.3% compared to 0.01% in the peripheral blood) with few residual tumor cells. Immunotherapy with autologous LMP2-CTL is therefore well tolerated in patients with relapsed EBV+ve HD/NHL and infused LMP2-CTL cells can accumulate at tumor sites and induce clinical responses.