Stem-cell transplant keeps neuromyelitis optica in remission

In a rare neuromyelitis optica spectrum disorder case, a man and a woman have stayed in remission for more than 15 years after allogeneic stem-cell transplants. Researchers say the results—plus a detailed look at immune reset and risks—justify moving toward a

For more than 15 years, two people living with a rare, devastating autoimmune disease have been able to live without the attacks that once derailed their bodies.

Their remission follows allogeneic haematopoietic stem-cell transplants—donor stem cells given in a single infusion—reported in Med. The study’s authors say the experimental approach merits a larger clinical trial. while also emphasizing that stem-cell transplantation carries serious risks and is unlikely to be appropriate for all patients.

The disease is neuromyelitis optica spectrum disorder (NMOSD). in which immune cells produce antibodies that trigger an assault on the spinal cord and on the nerve connecting the eye and the brain. Episodes typically arrive in attacks that can last for days or months. bringing eye pain. vision loss. vomiting. and weakness or paralysis in the arms and legs.

Standard treatments can prevent relapses for many people through ongoing medication, but in these two individuals, that prevention failed.

After treatment, the difference was stark. The man’s neurological function improved, allowing him to resume a normal life—and he went on to have two children. The woman was able to use her arms more effectively than before the transplant, and she no longer requires medication to reduce symptoms.

“I don’t think we can say it’s a cure, but then again, it has addressed the problem the disease has caused over this very long period of time,” says Jiao Jiao Li, a biomedical engineer at the University of Technology Sydney in Australia.

The transplant procedure used donor stem cells collected from the blood of another person. It has been used to treat some cancers, sickle-cell disease, and other blood conditions, but the study team says this is the first use of the therapy to treat NMOSD.

Massimo Filippi. a co-author and a neurologist at the IRCCS San Raffaele Hospital in Milan. Italy. and his colleagues report that the man was the first to receive the allogeneic transplant. in 2009. when he received stem cells from his sister. The woman received cells from an unrelated donor the following year. and both participants received a single infusion of their donor’s stem cells.

The key idea is that the transplant doesn’t just tamp down immune activity—it replaces it.

Before the stem-cell transplants. both participants received chemotherapy drugs called fludarabine and treosulfan. plus a monoclonal antibody drug designed to remove immune system B cells that produce the antibodies that attack the spinal cord and optic nerve. They also received a short course of antibodies and immunosuppressant drugs to prevent graft-versus-host disease. a common complication in stem-cell transplants in which donor cells attack the recipient’s healthy cells and can become life-threatening.

Li says the procedure completely replaces the person’s immune system. She contrasts this with other versions of the treatment that use a person’s own stem cells. which can “reset” the immune system but may not work as well for autoimmune conditions if the B cells that produce the harmful antibodies are not totally eradicated.

The authors report that neither participant developed antibodies associated with NMOSD, and that they developed healthy immune systems.

For Bruce Milthorpe, a scientist at the University of Technology Sydney, the long symptom-free period is what makes the findings hard to ignore. “Being able to keep these people symptom-free for a long period of time is exciting,” he says.

But he also points to the limits of what can be concluded from just two patients. “It is not clear whether a stem-cell transplant would benefit every person with NMOSD,” Milthorpe says, citing the study’s small sample size. Finding suitable donors can also be challenging.

Still, Milthorpe adds that the study could be used as evidence to start a clinical trial. He also highlights a practical detail in the method: the team obtained the stem cells directly from donor blood. a step he calls positive because it is less invasive than collecting stem cells from a person’s bone marrow.

The report also documents the costs of such an intensive intervention.

The participants developed negative outcomes, including swollen lymph nodes, an antibody deficiency that required treatment, and bladder cancer. Secondary cancers are not uncommon after stem-cell transplants. and the authors say the risks should be weighed against improvements in symptoms and quality of life.

The procedure itself remains dangerous in ways that reach beyond these two people. Infections that develop after treatment are described as the second most common cause of death associated with this therapy. The team says the procedure should be reserved for young people who do not see improved symptoms from standard treatment or have co-occurring autoimmune disorders.

All of these details land together in a reminder that even if a therapy can halt a devastating disease for years, it still has to earn its place—carefully, patient by patient.

The article was reproduced with permission and was first published on June 19, 2026.

stem-cell transplant neuromyelitis optica spectrum disorder NMOSD autoimmune disease immune system reset allogeneic haematopoietic stem-cell transplant graft-versus-host disease fludarabine treosulfan B cells monoclonal antibody clinical trial