Brother, Can You Spare Some Cells to Fight Kidney Cancer?
In this recent study, the researchers used an offshoot of a complex (and controversial) form of treatment used to fight cancers affecting the immune system or blood system (like leukemia) by exposing patients to extremely high doses of chemotherapy to destroy the cancer. The problem is, though, that the treatment also kills off all the patient's bone marrow, where the cells of the immune system are formed. So the patient then receives new bone marrow, or immune cells -- either his own that have been purged of disease, or from a closely matched, disease-free donor such as a sibling, child, or parent. But because the patient's immune system has been wiped out, he must remain in isolation to avoid infections until the donor bone marrow has a chance to build him a "new" immune system.
The current study involves a modification of this combination of chemotherapy and immunotherapy. The 19 patients were given enough chemotherapy drugs to suppress butnot destroy their immune systems. Each patient was then given immune cells from a sibling. The suppressed immune systems allowed the transplanted cells to "take" -- that is, to become one with the recipient's immune system.
"For whatever reason, the patient's body is telling us that the cancer has spread and their immune system is not successfully beating the cancer. The transferred [cells] from the sibling seem to be having significant effect," Linehan tells WebMD.
Study author Richard Childs, MD, medical oncologist and hematologist at the National Heart, Lung, and Blood Institute, explains further. He tells WebMD the immune systems of the donor and the recipient are quite different, even though they match, and in that difference lies the advantage: What the patient's immune cells are apparently unable to do, the donor's immune cells may be able to do.
"When you very suddenly replace the patient's immune system with a naive, healthy immune system in a setting where there's no tolerance, this is a way to break tolerance," Childs tells WebMD.
In an accompanying editorial, Shimon Slavin, MD, from Hadassah University Hospital in Jerusalem, agrees with the researchers. These donor cells have the capacity to attack the tumor the same way they would a foreign object, according to Slavin. Traditional cancer treatment may have overestimated the cancer-killing effects of chemotherapy and underestimated the ability of a donated immune system to help fight the cancer, he writes.