For the first time, researchers have reprogrammed the immune systems of MS patients to stop cells attacking the protective layer around nerves in the spinal cord.
The destruction of the insulating sheath – called myelin – prevents normal transmission of nerve signals, triggering symptoms of the disease such as limb paralysis.
The clinical trial showed that patients’ immune systems learned to recognise myelin as harmless. Further studies are expected to start shortly to confirm whether that in turn prevents relapses of the disease.
Northwestern University in Chicago, which took part in the research, hailed the study as a “big breakthrough”.
Researchers, working with scientists in Switzerland and Germany, took billions of white blood cells from nine patients and processed them to carry tiny fragments of myelin.
The cells were then re-injected, training the immune system to tolerate myelin.
Lead researcher Professor Stephen Miller said results showed the treatment stopped the body turning against itself – without the side effects of some other treatments that suppress the entire immune system, leaving patients vulnerable to infections and cancer.
“Our approach leaves the function of the normal immune system intact. That’s the holy grail,” he said.
Results published in the journal Science show that reactivity to myelin fell by between 50% and 75%.
Swiss authorities have already approved the next stage of clinical trials to confirm whether the treatment prevents progression of the disease. Experiments on mice show that it does.
“In the phase two trial we want to treat patients as early as possible in the disease before they have paralysis due to myelin damage,” said Prof Miller.
“Once the myelin is destroyed, it’s hard to repair.”
Dr Susan Kohlhass, head of biomedical research at the MS Society, said treatments that prevent progression of the disease are “urgently needed”.
“Being able to specifically stop the immune system attacking myelin but still keeping it fully functional poses an exciting potential therapy for people with MS,” she said.
“More research is now needed and we eagerly await the results of any future larger clinical trials of this therapy.”