Rejection is a big risk

Reducing the rate of acute rejection is important in kidney transplantation, as rejection reduces the chances that a transplant will remain viable in the long term by at least 50%.

Doctors try to minimise the risk by using drugs designed to dampen down the patient's immune system.

However, they are reluctant to use large doses of immunosuppressant drugs as this increases the risk of infection, and even of developing cancer.

So any alternative treatment could prove to be a real boon.

A team from Queen Elizabeth Hospital, Birmingham, examined whether administering antibodies may fit the bill.

In total, they reviewed eight trials covering 1,858 patients who underwent a kidney transplant.

Each patient was either given antibodies or a dummy treatment alongside standard immunosuppressant drugs.

Treatment with antibodies reduced the risk of acute rejection by 49% after six months.

And, crucially, infection rates were no higher in patients given the antibodies.

Blocking cell production

However, the researchers say that longer follow up studies are needed to find out whether the use of antibodies improves transplant and patient survival in the long term.

The antibodies work by binding to a particular receptor called interleukin-2.

This receptor plays a crucial role in the rejection process by triggering the activation of immune cells called T lymphocytes specifically which are designed to attack the transplanted kidney tissue.

When the antibodies bind to the receptor, it can no longer trigger the increased activation of these cells.

Mr Robert Johnson, a transplant expert from Manchester Royal Infirmary, told BBC News Online that antibody-based drugs were already available, but that many doctors were put off by their expense.

"There is every justification for their use, particularly as, if they are used in tandem with other immunosuppressants, they can replace other, much more toxic drugs such as cyclosporin," he said.

Over 15,000 people in the UK are currently living with a transplanted kidney.

The research is published in the British Medical Journal.