In some cases, yes, with a “mini-transplant.”

In a normal transplant, blood stem cells and immune cells are taken from the bone marrow or blood of the patient or from a well-matched donor. After the patient has high dose chemotherapy and radiation to destroy his own marrow, and, with luck, his cancer cells as well, the marrow or blood cells are re-infused into the patient to grow up a new immune system and blood. Both the high doses of therapy and, in the case of donor transplants, the new immune system, play important roles in fighting the cancer.

But high dose chemotherapy and radiation are very toxic. So doctors are experimenting with lower and lower doses of chemotherapy in patients with blood cancers who have not had a previous transplant and who have a donor available. (Mini-transplants do not work if the patient is his own donor, in part because it’s the foreign immune cells that seem to be crucial for killing cancer cells.)

So far, mini-transplants are used primarily for people with leukemia, lymphoma or myeloma, said Dr. Robert Soiffer, director of hematologic malignancies at Dana-Farber Cancer Institute. Success varies, depending on the type of cancer, but emerging data suggest mini-transplants are “at least as good as standard transplants” at putting patients into remission, he said.

At Johns Hopkins, Dr. Rick Jones, director of the bone marrow transplant program, added that mini-transplants “are not a panacea, but they do lessen the toxicity from high dose chemotherapy.” The chances of putting a cancer into remission are highest in people with slower-growing lymphomas.

OPTIONAL TRIM: In people with blood cancers who have had a previous transplant from a donor but have relapsed, another technique is also showing promise. It’s called a “donor lymphocyte infusion” and it means giving the patient another dose of the donor’s immune cells (often without any chemotherapy). These cells must come from the original donor because, as a result of the previous transplant, the patient’s immune system is now partly like that of the donor. Because these donor immune cells recognize the patient’s cells (both normal cells and those with cancer) as “foreign,” this booster infusion appears to energetically attack lingering cancer cells in the patient’s body.