Immune cells taken from one person may be able to join the battle against cancer in another, says a researcher.
Granulocytes help fight off invaders
New Scientist reported evidence that certain people seem to have cells with a more powerful ability to tackle cervical cancer cells in the test tube.
US scientist Dr Zheng Cui now wants to transplant more potent "granulocytes" into patients.
The finding has surprised some experts, who had thought granulocytes played a fairly minor role in fighting cancer.
The body's immune system helps beat infections, but also plays a key role in the destruction of cancer cells.
The idea that an infusion of souped-up immune cells, either from yourself or a donor, could help you in the struggle against cancer, is not new.
Test tube result
However, the research from Wake Forest University of Medicine in North Carolina points to a completely different cell as a potential saviour. Granulocytes are normally associated with the body's response to bacterial infections.
Dr Cui took blood samples from 100 volunteers, and mixed just their granulocytes with cervical cancer cells in the laboratory.
He found that one sample appeared to kill 97% of the cancer cells in just two days, while at the other end of the scale, after 48 hours, one sample had destroyed just 2% of the cancer cells.
Patients with cancer provided granulocytes with a lower than average cancer-killing ability, as did people who reported being stressed, or those over the age of 50.
Remarkably, even the time of year seemed to have an effect on the potency of granulocytes.
"Nobody seems to have any cancer-killing ability during the winter months from November to April," said Dr Cui.
In other research, granulocytes from a strain of mice completely resistant to cancer cured the disease when they were transplanted into other mice.
Dr Cui now plans human trials next summer to see if donor granulocytes - which are plentiful and easily harvested - can have a similar effect.
However, a British expert pointed to the possible risks of trials.
Although granulocyte transfusions are already given to some patients with depleted immune systems, they are normally irradiated to make sure that no other immune cells are given to the patient by mistake.
If this happens it can cause "graft-versus-host" disease, in which the donor cells recognise their new body as an invader, and launch an attack on it, with occasionally fatal consequences.
Dr John Gribben, an Cancer Research UK immunologist from St Bartholomew's Hospital in London, said that he would be surprised if Dr Cui got the go-ahead for the transplantation of "live" cells into a cancer patient.
"It's more than a theoretical risk, in my view," he said.
He said that the findings were surprising, and that more work needed to be done to confirm them in a wider variety of cancers, not just cervical cancers.
"There are quite a lot of people looking into the possibility of cellular therapies for cancer, but not working on granulocytes."