Canadian doctors have begun using stem cell transplants to treat "stiff person syndrome," a rare neurological condition in which a patient's leg and other muscles suddenly contract painfully, often leaving them immobilized like a tin soldier.
The disorder, which affects an estimated one in a million people, occurs when the immune system turns against a person's own tissues, in this case attacking cells in the brain and spinal cord.
Stem cell transplants have been used to treat patients with other auto-immune diseases, among them multiple sclerosis, scleroderma and Crohn's disease, but this may be the first time the procedure has been employed to alleviate the symptoms of stiff person syndrome, or SPS, the researchers reported Monday in the journal JAMA Neurology.
SPS is characterized by episodes of stiffness in the muscles and painful muscle spasms, which can be brought on by stress, loud noises or emotional distress. Some people with the disorder are so disabled they are unable to walk or move and may isolate themselves at home to avoid triggering an attack.
"Sometimes this happens when they're startled," said Dr. Harry Atkins of the Blood and Marrow Transplant Program at the Ottawa Hospital, who headed a team that transplanted stem cells into two women with the disease.
"So you can imagine walking across the street and someone honks the horn and you can't move, or you start falling and because your muscles can't move, you just fall and you hurt yourself," Atkins said Monday from Ottawa.
"It really does provide a barrier with just going on with your life."
Tina Ceroni of Toronto is one of the two SPS patients who had the stem-cell transplant — and she said it has given back her life.
The personal fitness trainer, now 36, started getting severe symptoms in her late 20s. Initially she was diagnosed with hyponatremia, or low blood sodium, thought to be related to her heavy training schedule for a half-ironman competition.
But when she tried to water-ski at a friend's cottage and had to be helped from the water because she was unable to move, Ceroni "knew that there was something definitely not right."
"My legs stiffened up like they were two complete boards. I had no ability to relax the muscles. They started to constrict to a point where I thought a bone might break or a tendon might rupture, and I was in pain for about eight hours."
She eventually was diagnosed with stiff person disease, which not only affected her legs but also the muscles in her arms and torso, leaving her unable to breathe properly when the muscles that control respiration would contract and go into spasm.
The year before her stem-cell transplant, she was rushed to the hospital 47 times because of life-threatening respiratory distress.
Ceroni had been living with her twin sister in Toronto but had to move back with her parents in nearby Burlington, Ont., because she couldn't be left alone.
"I started to withdraw from social events and social gatherings or being in a situation that was slightly unpredictable or if there was a potential for a loud noise, even walking down the street," she said. "If a car drove by and honked its horn and I was startled ... within minutes I could be on the ground.
"I wasn't able to live a normal life at all. The disease was dictating my life entirely. It became very, very isolating."
Ceroni had her stem-cell transplant in May 2011, and she said her symptoms have disappeared.
"My body doesn't react to noise. I can go to concerts now. I have no sensitivity to the triggers anymore."
The other patient, who was not identified, had her transplant in 2009, and she too has seen her symptoms abate, allowing her to return to work and resume activities such as skiing and cycling, the researchers reported.
"I think for the period we've commented on for both patients, they've done very, very well," said Atkins. "And it's nice to see them back enjoying life."
Conventional treatment involves a number of medications, including anti-anxiety drugs, muscle relaxants, anti-convulsants and pain relievers. Intravenous immunoglobulin can also reduce muscle stiffness and lower sensitivity to noise and other triggers. While such treatments can ease symptoms, they don't cure the disorder, and not all patients get relief from the drugs.
Still, Atkins stressed that not every patient with SPS would be considered for a stem-cell, or bone-marrow, transplant, which requires that the person's immune system be destroyed with high-dose chemotherapy before their previously removed and purified stem cells are reintroduced to create a new, disease-free immune system.
"It should only be considered where nothing more conventional is working ... the symptoms have to be severe and the impact on their life very, very profound because there are risks associated with this," he said, adding that one in 20 patients who receives a bone marrow transplant to treat leukemia, lymphoma or an auto-immune disorder will die of a complication.
"And we don't think stiff person syndrome patients ... would have a lower risk," he said.
There are also other complications from the chemo, including infertility and premature disorders such as heart disease and diabetes.
"I think for the right patient it might offer some benefit in helping them improve, but it's too early to say that this is the answer to stiff person syndrome. It's a pretty dramatic treatment and we need to keep thinking about better ways to do what we're doing — getting rid of the immune system perhaps with less toxicity and being able to grow back a new one more quickly.
"So I think there are a lot of unanswered questions yet."
Despite the risks, Ceroni said she had no qualms about going ahead with the transplant.
"I saw it as my only hope for a better future and my only hope to even lessen the disease. Any kind of improvement would have been remarkable for me.
"I saw this transplant as being given a gift of life, literally."