T cells cure leukemic mice.

A new treatment based on a type of white blood cell eradicates or slows an aggressive leukemia in mice. The finding holds out the hope that a similar therapy might aid humans with leukemia or other cancers.

T lymphocytes form the basis of the experimental therapy. Daniela Santoli of the Wistar Institute in Philadelphia and her colleagues harvested some of these small immune system cells from the blood of a child with acute T lymphoblastic leukemia. Then they allowed the cells to proliferate in culture. When these lymphocytes proved potent killers of a variety of test-tube-grown cancer cells, the researchers decided to test them against cancer cells proliferating in mice lacking an immune system. These mice have no T cells of their own to defend against a variety of diseases, including leukemia.

First, Santoli's team irradiated the human-derived T cells to ensure that these lymphoctyes died soon after completing their cancer-killing mission. Next, they treated the T cells with a substance known to rev up the cells' destructive potential. When injected with the cells, immunologically deficient mice with an early form of leukemia remained cancerfree for at least 2 months. This suggests the rodents "were essentially cured," Santoli says.

The same treatment also fought advanced leukemia, according to her group's report in the September JOURNAL OF CLINICAL INVESTIGATION. Among mice with severe disease that receive multiple injections of the revved-up T cells, half remained free of leukemia for at least 6 months. Though the rest continued to show symptoms of the cancer, they survived significantly longer than untreated mice.

Santoli hopes that, for humans, the treatment may be useful for mopping up any cancer cells that escape the surgeon's knife.