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Thirteen patients with metastatic melanoma who had not responded to standard treatments underwent a process called adoptive transfer. They were given immune cells produced in the laboratory specifically to destroy their tumors. Six of the patients experienced at least 50 percent tumor shrinkage, with no new tumor growth. In four additional patients some cancer growths disappeared.
In previous studies, the T cells would last only a few days, not long enough to do their job, according to NCI's Steven A. Rosenberg, M.D., Ph.D., senior researcher of the study. Improvements in the way the immune cells are generated in the lab and in the way patients' bodies are prepared to receive them made all the difference.
The scientists use a small fragment of each patient's melanoma tumor to grow T cells in the lab, using T cells taken from the patients. Exposure to the tumor activates the T cells to recognize and attack cells from that specific cancer. As the T cells were growing, patients were given chemotherapy drugs to diminish their immune systems so that the new T cells would have the opportunity to rebuild
the immune system. Once the T cells had multiplied to sufficient numbers in the lab, they were returned to the patients, who were also given a high dose of interleukin-2, a protein that stimulates continued T cell growth in the body.
The approach is still highly experimental, but Rosenberg and his colleagues are optimistic that adoptive transfer could be used to raise immune cells that will recognize and attack many tumor types, or to treat some infectious diseases,
such as AIDS.
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