The immune system in MS patients is restarted

Every day in Switzerland, one person is diagnosed with multiple sclerosis
.
Multiple sclerosis is an autoimmune disease in which a person's own immune system attacks the myelin sheaths
of nerve cells in the brain and spinal cord.
The disease causes symptoms
such as paralysis, pain, and permanent fatigue.
Fortunately, treatments have advanced
a lot in recent decades.
A study by the Department of Neuroimmunology and MS Research at the University of Zurich (UZH) and the Department of Medical Oncology and Hematology at the University Hospital Zurich (USZ) now clarifies why the most effective treatment currently available – stem cell transplantation – is so effective
.

Removes useless immune cells

"80% of patients are disease-free for a long time or permanently after receiving an autologous hematopoietic stem cell transplant," said recently retired Professor Roland Martin, who led the study and last author
.
This treatment is especially suitable for young people
with this disease.
Four years ago, Martin's department and USZ clinic were approved to administer treatment because of the high efficiency of treatment
and now low mortality.
This is the only clinic
in Switzerland that is licensed to perform this treatment.

During treatment, several chemotherapy methods can completely destroy the patient's immune system — including a subset
of T cells that mistakenly attack the autonervous system.
The patient then receives their own blood stem cell transplants, which are collected before chemotherapy
.
The body uses these cells to build an entirely new immune system without the need for any self-reactive cells
.

Systematic analysis of immune cells

"Previous studies have shown the basic workings of this approach, but many important details and questions remain to be solved
," Martin said.
Some unclear aspects are what exactly happens after the immune cells are cleared, whether any of them survive chemotherapy, and whether the self-reacting cells really no longer appear
.

In a recently published study, Martin's team systematically investigated these questions
for the first time by analyzing the immune cells of 27 MS patients who received stem cell therapy in Zurich.
The analysis was done before, during, and up to two years after treatment
.
This allowed the researchers to track how quickly different types of immune cells regenerate

Immune system reset successful

Surprisingly, the cells, known as memory T cells, are responsible for ensuring that the body remembers the pathogen and can respond quickly in case of a new infection, appearing
immediately after the transplant.
Further analysis showed that the cells did not re-form, but survived after chemotherapy
.
However, these remnants of the original immune system do not pose a risk of multiple sclerosis recurrence: "They are pre-damaged by chemotherapy and are therefore no longer able to trigger an autoimmune response," Martin explains
.

In the months or years following transplantation, the body gradually rebuilds different types of immune cells
.
The thymus gland plays an important role
in this process.
This is where T cells learn, so to speak, to distinguish between foreign structures, such as viruses, and their own structures
.
Martin said: "There is very little functional tissue
left in the adult thymus.
But after the transplant, the organ appears to regain its function and ensures the creation of a whole new pool of T cells, which apparently does not trigger multiple sclerosis or cause it to recur.

”

Further research is needed to gain wider approval

The findings allow researchers to understand why stem cell transplants are often so successful
.
But sadly, Martin said, the therapy is not approved
in many countries due to a lack of phase III studies.
"Phase III research costs hundreds of millions of euros, and pharmaceutical companies are only willing to conduct these studies
if they can make money later.
" This is not the case with stem cell therapy, as the drugs used are no longer protected
by patents.

"So I'm very pleased that we were successful in getting approval for the treatment from the federal public health office and that the health insurance company covered the cost
," Martin said.
In the past, many multiple sclerosis patients from Switzerland had to travel to Moscow, Israel or Mexico for transplants
.