Stem cell transplantation for severe rheumatism: restart the immune system
Stem cell transplantation can help with severe rheumatic diseases. Radical chemotherapy initially destroys almost all immune cells in the misguided immune system.
Immune system out of control A kind of admission control protects our body against the penetration of unwanted pathogens. Only cells that carry the most special protein combination of every human being on their surface are “let in” by the immune system. This biological defense system removes foreign substances that have entered the body and can also destroy the body's own defective cells. The immune system is vital and humans are therefore prepared for most infections. However, this control sometimes gets out of control and then fights the body's own cells instead of foreign bacteria and viruses.
Autoimmune disease with different forms One speaks in such cases of autoimmune diseases. The symptoms, which range from mild to sometimes even life-threatening, depend, among other things, on which cells the immune system fights. Rheumatic diseases are also part of it. Symptoms and manifestations are very different and depending on which proteins the immune system repels, there may be known joint complaints or the skin, kidneys and other organs may also be involved.
Unclear why some people get rheumatism So far it is unclear in many areas why some people get rheumatism and others don't. But there are some risk factors known that affect both the onset of rheumatic diseases and the individual episodes of the disease. "Genetic factors play a role, but also external influences such as infections, stress, hormones and sunlight," says Falk Hiepe, senior consultant at the medical clinic with a focus on rheumatology and clinical immunology at the Berlin Charité. Rheumatic diseases have particularly severe consequences if they are "systemic", that is, if the consequences of the disease occur in many parts of the body. In addition to the joints, skin and kidneys can also be affected very often, including kidney failure. In addition, there is a risk of circulatory disorders and functional restrictions in the heart, lungs and gastrointestinal tract.
Consistent treatment is important In order to avoid the risk of progressive organ damage, consistent treatment is particularly important in such diseases. In some cases, however, there were no helpful medications and so doctors came up with a treatment method known from cancer therapy, stem cell transplantation. Hiepe and his colleagues from the Charité reported on this extraordinary method at the last congress of the German Society for Rheumatology (DGRh) in Heidelberg and Mannheim. However, this is only possible in a few patients. Only if the organ involvement threatens severe long-term damage and medication cannot stop the progression of the disease, try the stem cell transplant. According to Hiepe, often with good results: "Some of our patients have had no relapse for over ten years."
Exchange of the immune system The patients owe their sudden improvement to the almost complete exchange of the immune system. Because radical chemotherapy initially destroys almost all immune cells, including those that are needed. However, since healthy immune cells are still urgently needed, blood is taken before chemotherapy. One speaks of a so-called "autologous" stem cell transplantation, since the stem cells come from the patient himself. However, since a sufficient number of these cells cannot be easily found in the blood, their production in the bone marrow is artificially stimulated. The resulting high number of stem cells in the blood stream then ends up in the blood bank, which serves as the basis for the later transplant. Harmful autoimmune cells and other blood cells are removed from this blood, so that a mixture rich in stem cells remains which can be transplanted after chemotherapy.
Disease activity declines after treatment The stem cells should then find their way into the bone marrow in order to build up a new, healthy immune system there, without autoimmune cells. So much for the theory. However, a few autoimmune cells can remain despite chemotherapy and careful sorting. "It cannot be ruled out that a small proportion of autoimmune cells remain in the body, nor that a few autoimmune cells are transmitted through stem cell therapy," says Hiepe. "But what we can say is that the disease activity usually drops significantly as a result of the treatment."
Successes in neurology Similar successes have also been achieved in another area of medicine, neurology. For example, autologous stem cell transplantation can be useful in multiple sclerosis, but is also rarely used here. "Treatment is only considered if multiple sclerosis is in an early, very active stage with many relapses and other treatment methods have little effect," said neurologist Lutz Harms, an expert in multiple sclerosis at the Charité in Berlin. The reason why this method is used rather rarely depends on the progress of other treatment methods, such as the administration of specific antibodies that are directed against autoimmune cells. According to Harms, this treatment is therefore an absolutely experimental therapy that could only be considered in very few multiple sclerosis patients.
Stem cell therapies are viewed critically Some neurologists warn of stem cell therapies. The German Society for Neurology (DGN) advises against these expensive and untested stem cell therapies for neurological diseases. "While stem cells have great potential in the development of new therapies, use in humans is still strongly discouraged," said Professor Alexander Storch at the DGN Congress. There are many expensive treatments in private clinics and practices that promise more than they deliver. "There is still no stem cell therapy for neurological diseases."
Side effects in the foreground New methods are also used for many rheumatic diseases. More specific drugs promise better results in the future, because the main problem with previously used drugs is that they dampen the entire immune system and often have many side effects if they are taken for years. "While there were no treatment options available in the past and those affected had to struggle primarily with the serious consequences of the disease, the side effects of the medication are now often in the foreground," says Hiepe.
One year for a new immune system Exactly these drugs would still remain vital, because without them the body's destruction would continue, possibly with severe organ damage. However, patients still have a certain susceptibility to infection even after a stem cell transplant, even if they should no longer need immunosuppressive agents after the treatment. With chemotherapy, almost the entire immune system was finally switched off and it took time to build up a completely new body defense. Hiepe explains that you have to expect at least one year for this process. In the future, it should be possible with the help of new active ingredients to specifically destroy autoimmune cells without harming the body's normal defense. Because even if a few immune cells could develop into misdirected autoimmune cells, the rest of them still provide vital health services. (ad)
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