'Killer' marrow transplant hope for leukaemia patients

London, Mar 23 : Patients with leukaemia who do not respond to conventional treatments may soon benefit from bone marrow transplants selected to target the cancer directly, thanks to a technique, pioneered in Italy, which uses transplants from family members who are not a perfect match.

'Natural killer' cells in the new bone marrow then attack the leukaemia, says Professor Andrea Velardi, from the University of Perugia in Italy.

Bone marrow transplantation has been around for a long time, and, in leukaemia, it is traditionally given to patients to replace bone marrow destroyed by powerful anti-cancer treatments.

However, one of the biggest problems in bone marrow transplantation is when the immune cells in the donated bone marrow 'reject' their new host.

They launch attacks, which can prove fatal in the worst cases, a condition called 'graft versus host disease'.

To avoid this, patients and donors are carefully screened to produce as perfect a match as possible.

However, some of the most recent research in bone marrow transplantation focuses on using the disease-fighting qualities of bone marrow to destroy cancer cells, either to prevent the disease coming back or to tackle it head-on, even where it is resistant to drugs and other treatments. Professor Velardi is looking for ways to harness these qualities without raising the risk of graft versus host disease.

He has been using donors from the patient's own family who are only a partial match - sharing only 50percent of their genetic material.

He found that in some cases, immune cells called 'natural killer' cells were active in the donor bone marrow after transplantation, and could launch an effective attack on the leukaemia cells, and that he could predict in advance, using tests, how effective that would be.

In a small group of patients with acute myeloid leukaemia , the survival rates improved when this kind of transplant was given with the patient already 'in remission' - cleared of the disease by chemotherapy.

However, it significantly increased survival - from 2percent to 30percent, among those patients whose disease had not responded fully to treatment prior to the transplant.

"For patients considered ineligible because of chemo-resistant leukaemia, this is a potentially life-saving advancement. It's likely to make enormous changes in the practice of transplantation worldwide," BBC quoted him, as saying.

The study is due to be presented at a bone marrow transplantation research conference in London.

ANI