ASBMT 2001 Best Abstract Awards
Biology of Blood and Marrow Transplantation
The risk of EBV-associated Lymphoproliferative Disease (EBV-LPD) ranges from 5-25% after T-cell-depleted BMT from an unrelated or a mismatched-related donor. From 1993-99, we generated donor-derived EBV-specific CTLs and administered them as prophylaxis and treatment for this complication. 59 patients received a T-cell-depleted BMT from a matched unrelated or a haploidentical family donor. 56 patients received CTLs prophylactically. The 4 year overall survival is 71%. 13 patients died of
... of their primary disease and 3 of infection. Only 2 patients developed exacerbations of preexisting GVHD within 1 month post infusion. 9 of the patients on the prophylaxis study had evidence of incipient EBV-LPD prior to CTL infusion. In 6 patients the abnormalities resolved without sequelae after CTL infusion. The other 3 developed local inflammation during a therapeutic response with one developing adenoid enlargement with necrosis, one developing fever and a LLL pulmonary infiltrate and the third, a transient elevation in transaminases. None of the 56 patients in the prophylaxis study developed EBV-LPD compared to an incidence of 11.5% in patients not receiving prophylaxis. 4 patients not enrolled on the prophylaxis study received CTLs as treatment for EBV-LPD. One patient with a mutation in EBNA 3b was resistant to CTL therapy and 2 patients attained remission after CTL therapy. The CTLs of the first 26 patients were marked with the neo gene to track their persistence. Real time PCR assay showed the marker gene persisted for up to 78 months in peripheral blood. Multiple integration sites were demonstrated on inverse PCR studies confirming the persistence of multiple clones. Polyclonal donor-derived EBV-specific T-cell lines can be used safely to prevent EBV-LPD post allo-BMT with long-term persistence of adoptively transferred cells. However infusion of CTLs to patients with active or incipient disease may produce morbidity secondary to tissue inflammation at sites of disease. REAL-TIME IN VIVO IMAGING OF EXPANDED CD8+ NK-T CELLS INFILTRATING AND ERADICATING LYMPHOMAS Edinger, M.; Cao, Y.; Verneris, M.R.; Bachmann, M.H.; Contag, C.H.; Negrin, R.S. Stanford Medical School, Stanford, CA Revealing the mechanisms of neoplastic disease and enhancing our ability to intervene in these processes requires an increased understanding of cellular and molecular changes as they occur in living animals. Since light is transmitted through mammalian tissues, cells expressing the bioluminescent reporter gene luciferase can be detected within living mice using low light imaging cameras. To establish animal models of leukemia and lymphoma, the B cell lymphoma lines A20 and BCL1 were labeled with a luciferase reporter gene. Tumor engraftment was visualized after sc, ip and iv injections. As few as 7000 cells were detected after iv injection. Measuring light emission over time enabled us to quantify tumor growth within internal organs. Following iv injection of 10 4 A20luc cells in a syngeneic BMT model, tumor infiltration in the BM of femurs, humeri, sternum and vertebrae was observed. Using these tumor models we investigated the therapeutic application of a cytotoxic cell population, previously described as cytokine induced killer cells (CIK). These cells co-express T cell and NK cell markers and are generated from splenocytes by stimulation with IFN-γ on day 0, followed by anti-CD3-Ab and IL-2 stimulation and expansion over 2-3 wks. Treatment of A20-luc tumor bearing animals with CIK cells led either to a complete eradication or significant attenuation of tumor signal from sc growing tumors. To examine trafficking of these effector cells in vivo we used a retroviral transduction system to label the cells with a gfp/luciferase fusion protein. Shortly after iv injection transduced cells were detectable in the lungs, 16h later they were located in liver and spleen and infiltrated a sc growing A20 tumor after 72h. They were detectable at this tumor site for the following 9 days until the tumor was finally eradicated. Using this system, unique insights into dynamic biologcal processes can be readily visualized. ASBMT Best Abstract Awards The ASBMT Abstract Review Committee selected the following two abstracts for the annual Best Abstracts Award.