The therapy takes advantage of the immune system's ability to deliver a specially targeted assault on an unwanted invader, and helps boost that assault by multiplying the number of immune cells involved inside the patient's body. This approach may also work for treating other cancer type, as well as infectious diseases, such as AIDS, according to the researchers.
Unlike many other cancer studies, which are done on mice, this study was done on human patients, who had not responded to standard therapies.
"To be able to do something as complex as this in humans, where every human is different and every tumor is different, has been quite difficult," said study author Steven Rosenberg of the National Cancer Institute.
The body's immune system can produce a set of T cells that attack tumors, but often these alone aren't a match for aggressive cancer. In the past, researchers have tried to boost these cells' numbers by extracting some from patients, inducing them to multiply in culture, and then transferring the expanded population back into the patients. The cells generally failed to "stick," however and disappeared quickly after the transfer.
By suppressing the patients' immune systems to "make room" for the new cells, as physicians do during a tissue transplant, Rosenberg and his colleagues induced the transferred cells to remain and grow in the body and start killing the tumor cells. In two cases, the transferred cells repopulated the patients' blood, becoming the dominant type of active T cell.
"It's very rare to be able to sustain large numbers of T cells in the body," said Rosenberg. "When your body fights the flu, maybe three percent of the
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Contact: Lisa Onaga
lonaga@aaas.org
202-326-7088
American Association for the Advancement of Science
19-Sep-2002