A radical treatment can halt the progression of multiple sclerosis and even reverse symptoms of the autoimmune disease, research suggests.

The "highly exciting" therapy involves destroying the patient's immune system and regenerating a new one using stem cells taken from their bone marrow.

A 13-year trial involving 24 people with a highly active, relapsing form of MS saw 70% of patients experience a complete halt in the disease's progression.

In 40% of patients, symptoms such as vision loss, balance problems and muscle weakness were reversed for prolonged periods of time.

Although doctors say the findings hold a lot of promise, experts have warned the treatment can have serious side effects and risks.

It is also thought the therapy will only help a small proportion of patients in the early stages of MS - and patients who have had significant disabilities for a prolonged period of time are unlikely to benefit.

One of the main dangers associated with the therapy is the threat of infection for patients while they are unprotected by an immune system.

The treatment is known as IAHSCT (immunoablation and autologous hematopoietic stem cell transplantation) and a similar procedure has been used for treating patients with life-threatening leukaemia for several decades.

Jennifer Molson, who participated in the MS trial six years after she was diagnosed with the disease, said: "Before my transplant, I was unable to talk or work and was living in assisted care. Now, I am able to walk independently, live in my own home and work full time.

"I was also able to get married, walk down the aisle with my dad and dance with my husband. I've even gone downhill skiing."

The MS Society in the UK has welcomed the findings, published in the Lancet journal, as it "provided valuable information about the long-term safety and effectiveness" of the treatment.

Professor Siddharthan Chandran, from the Medical Research Council Centre for Regenerative Medicine at the University of Edinburgh, said the study appeared to render some of the patients in the study "effectively disease-free".

He added: "However, the treatment regime has substantial risks and safety concerns that underline the need for future studies with a larger sample size, control group and ideally identification of predictive markers to allow targeting of this treatment to those MS patients at greatest risk of rapid and severe decline."