Immune cells 'beat cancer'

Patients with skin cancer were studied

Specially trained immune cells are being harnessed to shrink tumours in cancer patients.

US researchers used the cells to treat patients with skin cancer who had not responded to other therapies, and saw "promising" results.

They hope more research will allow the technique to be used to treat different types of cancer and infectious diseases such as Aids.

Scientists treated 13 patients with metastatic melanoma, a deadly form of skin cancer.

There is probably a genuine step forward here

Dr Lesley Walker, Cancer Research UK

They were given immune cells created in the laboratory to destroy tumours in a process called adoptive transfer.

In six patients, tumours shrunk by at least 50%, and there was no growth or appearance of new tumours.

Four patients saw some cancer growths disappear.

Knocking out cells

The treatment takes T cells, immune cells that recognise and fight foreign cells in the body.

Researchers removed a small fragment of each patient's tumour and some T cells from the patient.

Exposure to the tumour activated the immune cells so that they would recognise and attack cells from each specific cancer.

Once enough specially trained T cells had been grown to use as a treatment they were given to the patient.

They were also given a high dose of a protein called interleukin-2 which stimulates continued T cell growth in the body.

To prime patients for the treatment, they were first given chemotherapy to knock-out their own immune cells which had been unable to fight the cancer, making room for the new, improved cells.

These T cells multiplied in the body and were able to attack the tumour cells, and took over the patient's immune system enabling it to fight the cancer for several months.

However, patients' old immune systems did recover, restoring their ability to fight infections.

Generating cells

Researchers said patients in the study only suffered occasional infections and mild autoimmune disorders during their treatment.

They admit their research is highly experimental, but say it is a significant step forward in the use of immune cells to fight cancer.

Dr Steven Rosenberg, of the National Cancer Institute, who led the research, said: "In the past, only a fraction of the cells were able to survive, and they would persist only for a few days."

But he said improvements in the way immune cells are generated in the laboratory and the way patients' bodies are prepared to receive them, have led to more successful treatments.

"We have been able to generate a very large number of immune cells that appear in the blood and constitute a majority of the immune system of the patient.

"These persist for over four months and are able to attack the tumour."

Individualised therapy

Dr Lesley Walker, head of cancer information at Cancer Research UK said the research was significant, but much more needed to be known about its effects on the body.

She told BBC News Online: "There is probably a genuine step forward here in that they are very careful in picking the T cells that they are growing up, and they are selecting really promising clones for use in patients.

"And they are using chemotherapy to basically make room for these immune cells. I think that really is a step forward."

But she said it was not yet clear how transient the treatment's benefits might be or what long term effects it could have on a patient's health

She added that the therapy was highly individualised, and had only been shown to work for a small number of patients.

The research is published in the journal Science.