Study author Martin: '80 percent of patients remain disease-free long-term or even forever following an autologous hematopoietic stem cell transplant'

A study conducted by the University of Zurich's (UZH) Department of Neuroimmunology and MS Research and the University Hospital Zurich's (USZ) Department of Oncology and Haematology Clinic has examined how blood stem cell transplantation treats multiple sclerosis (MS) and how the immune system heals afterward according to a UZH News article published on October 11.

MS is an autoimmune disease in which a person's immune system attacks the myelin sheath of nerve cells in the brain and spinal cord. It's a very common condition, with one person in Switzerland diagnosed with MS each day. MS leads to symptoms including paralysis, pain, and permanent fatigue. Fortunately, recent years have brought great advances in therapeutic treatments.

“80 percent of patients remain disease-free long-term or even forever following an autologous hematopoietic stem cell transplant,” said retired professor Roland Martin, who was also the study lead and one of its authors.

The treatment is especially suitable for younger people with aggressive forms of MS. Four years ago, Martin's department and the USZ clinic were given approval for administering the therapy due to its high effectiveness and low mortality rate. Currently, the USZ clinic is the only clinic in Switzerland to get this approval.

During the treatment, various chemotherapies are used to completely destroy the patient's immune system, including the subset of T cells that mistakenly attack their own nervous system. The patient then receives a transplant of their own blood stem cells, which were collected prior to chemotherapy. The body uses the cells to create a completely new immune system without any autoreactive cells.

“Previous studies have shown the basic workings of the method, but many important details and questions remained open,” said Martin.

Martin's study aimed to learn more about the minute details of the treatment by analyzing the immune cells of 27 MS patients who received stem cell therapy in Zurich. The analysis was conducted before, during, and up to two years following treatment. This allowed the researchers to better monitor how quickly each type of immune cell regenerated.

Surprisingly, the study revealed that memory T cells, which ensure that the body remembers pathogens and can quickly react in the case of a new infection, immediately reappeared after the transplant. Further analysis showed that the cells had not re-formed, but had actually survived the chemotherapy. The remnants of the original immune system also posed no risk of MS recurrence.

“They are pre-damaged due to the chemotherapy and therefore no longer able to trigger an autoimmune reaction,” said Martin.

In the months and years following the transplant, the body gradually recreates the different types of immune cells, with the thymus gland playing an important role in the process. The gland serves as a "school" for T cells, teaching them to tell foreign structures, such as viruses, from the body's own.

“Adults have very little functioning tissue left in the thymus,” said Martin. “But after a transplant, the organ appears to resume its function and ensures the creation of a completely new repertoire of T cells which evidently do not trigger MS or cause it to return.”

While the study's findings have provided valuable insight into the success of stem cell transplants, Martin said that the treatment isn't approved in many countries due to the lack of phase III studies.

“Phase III studies cost several hundred million euros, and pharmaceutical companies are only willing to conduct them if they will make money afterward," he said. However, this isn't the case with stem cell therapy, as the drugs used are no longer patent-protected.

“I am therefore very pleased that we have succeeded in obtaining approval for the treatment from the Federal Office of Public Health and that health insurers are covering the costs,” Martin said. In the past, many Swiss MS sufferers had to travel to Russia, Israel or Mexico to receive transplants.