Haemophiliacs will anxiously await news of more positive outcomes from the ongoing medical research

Karin Pappenheim Haemophilia Society

But scientists from three hospitals in Boston, USA, found that they could temporarily reverse the effects by extracting skin cells from patients whose DNA can't make factor VIII.

The connective cells, known as fibroblasts, are then isolated and an electrical current is used to force-feed them with the snippets of DNA that make factor VIII.

The fibroblasts are grown in a test tube and then implanted into tissue near the stomach.

Tests on six volunteers showed success in four of the cases. These patients needed fewer injections to stop their uncontrolled bleeding.

And in two of these patients the factor VIII levels were high enough to bring the level of their disease from "severe" to either "mild or moderate" haemophilia.

But scientists found that within just 10 months after the experiment all signs of improvement had disappeared.

The team, led by Dr David Roth, director of haemophilia research at the Beth Israel Deaconess Medical Centre, said the test has been carried out on another six patients, but that these results are not ready.

Reject tissues

Dr Roth said the studies showed that the technique of transplanting cells could be carried out safely.

"Nobody hit normal levels of factor VIII in the blood, but that wasn't our goal.

"We believe the cells have the potential for a durable effect."

Scientists are now working to ensure the body does not reject the implanted tissues.

Karin Pappenheim, chief executive of the Haemophilia Society said: "The findings from the United States look to be encouraging. The haemophilia community have a strong interest in any new forms of treatment which avoid the invasive methods of treatment which are currently available.

"Haemophiliacs will anxiously await news of more positive outcomes from the ongoing medical research."

The report is published in the New England Journal of Medicine.