Scientists feel that they have found a innovative way to fight deadly cancers: increase a patient's immune cells in the laboratory to recognize and fight the patient's own tumor, then inject the cells back into the body and let them go to work.
Known as adoptive transfer, the experimental technique involves the body's T cells, which are responsible for finding and attacking foreign cells that have entered the body. In the experiment, the scientists extracted some of these cells from 15 patients suffering from the deadly form of skin cancer, melanoma, then exposed them in the laboratory to a small segment of the patient's tumor. The cells learned to recognize the tumor fragment as a foreign body and fight it. Additionally the cells also multiplied, providing enough cells to replace the patient's existing immune system, which had proven ineffective at fighting the cancer on its own.
The researchers then used chemotherapy to destroy the patient's ineffective immune system and replaced it with the T cells grown in the laboratory. In 10 of the 16 patients, the treatment resulted in at least a 62 percent shrinkage of the tumors, with no re-growth or appearance of new tumors. Some tumor disappearance was noted in four other patients. The effects lasted for four months, at which time the patient's own immune system recovered and took over its usual job of fighting infections.
The technique, say the investigators, is a major improvement over past attempts to treat cancer with immune cells. Steven A. Rosenberg, M.D., Ph.D., "In the past, only a fraction of a percent of the cells we injected were able to survive, and they would persist for only a few days." In this study, he continues, "We have been able to generate a very large number of immune cells that appear in the blood and constitute a majority of the immune system of the patient. These persist for over four months and are able to attack the tumor."