A man and woman with a rare and devastating autoimmune disease have been in remission for more than 15 years after receiving a stem cell transplant. The positive results, reported in Withsuggest the experimental treatment warrants a larger clinical trial, scientists say.
Both people suffered from a serious and life-threatening condition in which immune cells produce antibodies that trigger an attack on the spinal cord and nerve connecting the eye and the brain, leading to a condition called neuromyelitis optica spectrum disorder (NMOSD). Symptoms tend to appear in episodes that last days or months and include eye pain, vision loss, vomiting, and weakness or paralysis affecting the arms and legs. Current treatments can prevent these episodes with continued medication, but they did not work in these two people.
After the stem cell transplant, the man’s neurological function improved and he returned to a normal life and had two children. The woman was able to use her arms more effectively than before her treatment and no longer required medication to reduce symptoms.
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“I don’t think we can say it’s a cure, but again it solved the problem that the disease caused over a very long period of time,” says Jiao Jiao Li, a biomedical engineer at the University of Technology Sydney in Australia.
In the treatment, called allogeneic hematopoietic stem cell transplantation, a donor’s stem cells are taken from another person’s blood. The procedure has been used to treat certain cancers, sickle cell disease and other blood diseases. Massimo Filippi, study co-author and neurologist at IRCCS San Raffaele Hospital in Milan, Italy, and colleagues say this is the first use of this therapy to treat NMOSD.
The man was the first to undergo an allogeneic transplant, receiving stem cells in 2009 from his sister. The following year, the woman received cells from an unrelated donor. Both participants received a single infusion of stem cells from their donor.
Being able to keep these people symptom-free for a long time is exciting, says Bruce Milthorpe, a scientist at the University of Technology Sydney.
Immune System Reset
Before the transplant, participants received chemotherapy drugs called fludarabine and treosulfan as well as a monoclonal antibody to eliminate immune system B cells that produce the antibodies that attack the spinal cord and optic nerve.
Before receiving their stem cell transplant, both individuals also received a short course of antibodies and immunosuppressive drugs to prevent the donor’s cells from attacking the recipient’s healthy cells, also known as graft-versus-host disease, a common complication after a stem cell transplant. The complication can be life-threatening, Li says. Neither person developed antibodies associated with NMOSD and developed healthy immune systems, the study report authors report.
Li says the procedure completely overrides the person’s immune system. While other versions of the treatment that use a person’s own stem cells reset the immune system. However, these versions might not work as well for people with autoimmune diseases if the B cells that produce the attacking antibodies aren’t completely eradicated, she adds.
Milthorpe says it’s unclear whether a stem cell transplant would benefit all people with NMOSD, due to the study’s small sample size. It may also be difficult to find suitable donors. But the study could serve as evidence to launch a clinical trial, he adds.
The team’s method of obtaining stem cells directly from donor blood is also a positive development, says Milthorpe, because it is less invasive than harvesting stem cells from a person’s bone marrow.
The authors say both participants also developed negative outcomes, including swollen lymph nodes, antibody deficiency requiring treatment, and bladder cancer. The development of secondary cancers is not uncommon after a stem cell transplant, and the authors say the risks must be weighed against improvement in symptoms and quality of life.
Stem cell transplants themselves are also risky. Infections that develop after treatment are the second leading cause of death associated with this treatment. The team says the procedure should be reserved for young people who don’t see improvement in symptoms with standard treatment or who have co-occurring autoimmune diseases.
This article is reproduced with permission and has been published for the first time June 19, 2026.
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