This is a major clinical achievement which looks likely to save many lives

Dr David Grant, Leukaemia Research Fund

One of the most common problems caused by CMV in bone marrow transplant patients is a form of lung infection similar to pneumonia.

The LRF estimates 15% of transplant patients receiving a transplant from a donor will suffer from such an infection after a bone marrow transplant. Between 80-90% of them will die.

In 1998, 3,000 patients in the UK received a transplant, with 714 of these being transplants from a donor.

A transplant is required when bone marrow fails to produce blood cells properly.

To restore normal blood cell production, the patient is given healthy stem cells - the mother cells from which all new blood cells are formed.

If this cannot happen, bone marrow fails and patients may die from infection or bleeding.

Dr Mackinnon said: "We believe we may have found a way to supply primed immune cells to bone marrow transplant patients in order to fight off CMV infection."

'Life-saving'

The UK trial involved 13 patients with Cytomegalovirus.

Six who were given specially primed T-cells were able to overcome their CMV.

A further six were cleared of CMV after they had taken antiviral drugs in addition to the cell treatment.

All 12 were free of the virus nine months after the procedure. Most complications are likely to develop in the first 100 days after transplantation when the patient's immune system is weakened.

The treatment involved taking a blood sample from the bone marrow donor, then culturing the cells in the laboratory and infusing them with protein from the inactivated CMV virus.

More trials needed

These cells then tell the immune cells (T-cells) from the donor to generate an 'extra-strong' response to the CMV virus.

Dr David Grant, scientific director of the LRF which funds the research University College London, said: "This is a major clinical achievement which looks likely to save many lives."

But he said further trials had to be carried out in larger groups of patients.

He added: "This will have a major impact on the use of bone marrow and stem cell transplantation.

"The more we are able to refine the technique the more lives we will save and the less punishing treatment will become."

The treatment of patients needing bone marrow transplants is improving on many fronts, say researchers, with better matching of donors and recipients, developments in the use of stem cells, and reducing the risk of complications from the procedures.