Patients regularly reach out and ask me about something called HSCT.
“What is HSCT?” and is it proven as a therapy?
Often the patients asking about this have multiple sclerosis (MS) or some other autoimmune disease.
I’m not a physician so I can’t give medical advice, but as a stem cell biologist here at UC Davis School of Medicine I give them my perspectives. I’ve been following the idea of stem cells and more specifically of HSCT for MS and other conditions for many years.
The goal of today’s post is to provide a general overview of HSCT. At the same time, there is great interest in HSCT for MS and other autoimmune diseases so I will discuss that as well.
What is HSCT?
The HSCT abbreviation stands for hematopoietic stem cell transplantation. Sometimes I have also seen people use the HSCT acronym for the related term, hematopoietic stem cell therapy or even say HSCT therapy, but that is rarer.
The transplanted cells here are mostly bone marrow stem cells but can also come from peripheral blood or umbilical cord.
Bone marrow stem cells are now often given the more specific name hematopoietic stem cells. Some hematopoietic stem cells also circulate in the bloodstream. More marrow stem cells can be mobilized into the blood with specific drugs like GSCF.
You can read the moving story of a young donor of peripheral blood stem cells.
Depending on where the stem cells come from, the transplants can be an allogeneic HSCT (from a donor) or autologous, which uses your own cells. The autologous approach is called AHSCT.
Why use hematopoietic stem cell transplantation?
HSCT is used to replenish blood stem cells.
Typically it is given after chemotherapy. The rationale is that chemo destroys some or all of the immune system and HSCT can replace that loss.
The chemo associated with HSCT is most often used to kill blood cancer cells or more rarely other kinds of cancer cells. It can also kill defective cells that cause immune disorders. This is in part where it can play a role in treating MS, scleroderma or other autoimmune disorders. However, that hasn’t been approved in the U.S. yet.
With current technology, it is difficult to specifically kill just the cancer cells so unfortunately the chemo also kills many normal cells. Some types of cells are more sensitive to chemo than others including the hematopoietic stem cells and other cells in the marrow.
With chemo that is strong enough to kill essentially all of the blood cancer cells, the immune system may be destroyed too or severely damaged. In order for patients to survive they need a new complement of hematopoietic stem cells to replenish their immune systems. That’s where HSCT comes into play. The goal is to give the patient a restored immune system, which is necessary for survival.
There are major risks here including death and immune problems, but for some lethal conditions like certain cancers or severe immune disorders, the risks are likely worth it for some patients. You should consult your doctor if you are considering HSCT for yourself or for a family member.
Another risk is graft versus host disease or GvHD, where the transplanted immune cells attack the patient who gets them. This is a risk for allogeneic transplants. Sometimes the transplanted cells view the host as foreign and so attack. Interestingly there is hope that other kinds of stem cells like MSCs may help patients who develop GvHD by turning down immune system activity.
HSCT for MS and other autoimmune disorders
In MS the patient’s immune system attacks specific brain cells. This causes cell death and damage to the brain. MS can damage other parts of the central nervous system too such as the spine and optic nerves.
Researchers came up with the idea of trying to reboot the immune system in MS. If you give MS patients chemo then it might kill off the auto-reactive immune cells. Those are the cells responsible for the body’s attack on its own nervous system. Then HSCT replaces the now dead immune cells. If all goes well, the transplant generates a new complement of hopefully non-auto-reactive immune cells. This approach is autologous, meaning that your own previously isolated hematopoietic stem cells are given back after the chemo.
In certain patients these stem cells produce normal non-autoreactive mature blood cells so you have fewer symptoms of autoimmune disease.
Extensive research suggests this approach works for some but not all MS patients. It also seems to help some patients with other autoimmune diseases too.
There are serious risks here, but for patients with severe MS or other autoimmune diseases it may be worth it. Again, talk to your doctor.
Looking back and ahead
I’ve written before about the now defunct Dr. Burt HSCT treatment for MS program. I had several concerns about that program at Northwestern. However, many of his patients wrote me or left comments here on The Niche in support of Dr. Burt. They feel the HSCT really helped them. On the other hand a few patients have died as well so that can’t be ignored.
Burt published a new paper that looks generally encouraging: Real-world application of autologous hematopoietic stem cell transplantation in 507 patients with multiple sclerosis.
Because of HSCT research, the future is more encouraging for some patients with autoimmune diseases.
The UK MS Society has a nice diagram (above) explaining HSCT for MS and some good resources.
Note that many unproven stem cell clinics sell adipose cell-based or other kinds of stem cell interventions for MS, which are entirely unproven and have their own risks.
- UK MS Society diagram explaining HSCT for MS
- 2022 Dr. Burt HSCT for MS paper: Real-world application of autologous hematopoietic stem cell transplantation in 507 patients with multiple sclerosis.
- Review article on HSCT for multiple sclerosis