I have touched on this topic several times in the past in congress reports – in view of a currently increasing demand, I would like to go into more detail on HSCT (= engl. Hematopoietic Stem Cell Transplantation) today – also to prevent misconceptions.
Many MS sufferers think of stem cells as a “renewal” of their own tissue and not infrequently the term “stem cell transplantation” is associated with the hope of restoring a lost function and reversing disability.
In principle, this idea is not wrong, yet the objective of autologous hematopoietic stem cell transplantation – which is currently being discussed very intensively – is different from what is commonly assumed. It is actually quite similar to the principle of current drug MS therapy (“early and efficient treatment”).
In HSCT, after appropriate preparation, so-called hematopoietic stem cells are removed from a patient’s body. Hematopoietic stem cells are precursor cells of the blood-forming system (blood formation = hematopoiesis), including the precursors of white blood cells, which are responsible for fighting disease-causing agents, but also for the development of autoimmune diseases such as multiple sclerosis.
After these precursor cells have been obtained, the remaining part of the blood-forming system in the same patient is “destroyed” by aggressive chemotherapy, i.e. the patient no longer has any functioning white blood cells (immune cells) after this procedure and would not be able to defend himself against pathogens in this state. Since such a condition is incompatible with normal life, he is now reintroduced to the previously removed hematopoietic stem cells, in the hope that they will settle back into the body, multiply and start blood formation again.
As a rule, it works very well to restore the immune system in this way (reconstitute). But one can also imagine that the whole procedure is not entirely safe, even though the technology has now advanced to the point where serious complications or deaths are becoming increasingly rare.
The idea behind the procedure is to “flatten” the “old” aggressive immune system, which causes severe MS, and then give your own immune system a “second chance” to regenerate itself less autoaggressively. In many cases, this “reset” of the immune system works very well. Recent studies on HSCT show that active MS after HSCT is significantly less severe. Experts now believe that HSCT is the most effective anti-inflammatory therapy we currently have available.
However, it should also be clear from the presentation that HSCT does not “cure” MS – and the measure is also not able to restore body functions in a patient who is already severely affected. HSCT is primarily a measure that should be offered to patients with a very active disease as early as possible in the course of the disease, especially when complete stabilization is not achieved with effective drug therapies. The goal of the measure is – analogous to the early use of highly efficient drug therapies – to prevent physical and mental deficits from occurring in the first place. Since HSCT is also not entirely safe, a trial therapy with efficient anti-inflammatory drugs should precede HSCT. If this strategy does not work sufficiently, HSCT is an interesting option, the importance of which will increase in the future in my opinion.
The method is not suitable – as already mentioned – for patients with a long course of disease without significant inflammatory activity – here we know from previous studies that the benefit-risk ratio of a HSCT is probably no longer given.
