Clinical trials on six multiple sclerosis (MS) patients who have had stem cell injections have produced "encouraging" results, scientists say.
The trials, which are thought to be a world first, are taking place at Frenchay Hospital in Bristol.
The six were injected with stem cells harvested from their own bone marrow. Research found this increased nerve function by up to 20%.
The team is planning a much larger trial of the technique.
MS is a nervous system disorder that affects around 40 in every 100,000 people in the UK.
It can lead to a variety of symptoms, including muscle weakness, fatigue, loss of co-ordination, visual and speech difficulties.
The Bristol study, undertaken by a team from the University of Bristol, collected and filtered hundreds of thousands of the patients' PCT stem cells from their bone marrow while they were under general anaesthetic.
The cells, which are known to transform into other forms of cell and repair damage, are injected en masse into the patients' bloodstream.
Because the cells come from the patients' own bodies there are no ethical issues surrounding their use.
Study leader Prof Neil Scolding stressed to the BBC that the research was still in its infancy.
"We didn't see patients throwing away their wheelchairs, throwing away their walking sticks, the symptoms that the patients had didn't change a great deal.
"They didn't get a lot worse over the 12-month period - and you might have expected them to - but neither was there a great difference in what patients could actually do. So this is just a beginning."
Liz Allison, one of the volunteers being studied, said: "My long-term hope is that stem cell research will be a cure for MS and will be available for everyone who is afflicted with this disease.
"It has the added benefit of being a relatively pain-free procedure and having no side effects."
Prof Scolding said he was encouraged by this early study, the data from which may indicate that stem cells can stabilise MS.
"A larger study is required to assess the effectiveness of bone marrow cellular therapy in treating MS.
"We are hopeful that recruitment to this phase 2/3 study may begin towards the end of this year."