Introduction
The immune system is the barrier that protects the body from the penetration of pathogens. It consists of a cellular and a so-called humoral part. Cellular components are for example the macrophages (“scavenger cells”), the natural killer cells and the lymphocytes.
The humoral part, i.e. the part that is not made up of cells, contains, among other things, antibodies and various vector substances known as interleukins. Under normal circumstances, i.e. in a healthy organism, the immune system is able to differentiate between the body’s own structures and those that are foreign to the body. Structures that are recognized as foreign are then eliminated by the immune system.
Sometimes, however, our immune system is defective. In such a situation, it wrongly recognizes the body’s own tissue as foreign, an immune reaction is triggered and the body begins to attack itself. This is called autoimmune diseases.
Examples of such diseases are rheumatism, multiple sclerosis or Crohn’s disease. In such cases, drugs are used which keep the immune system in check and downregulate, the immunosuppressive drugs. They dampen immune reactions and thus prevent the immune system from developing its effectiveness. In addition, immunosuppressants are also used to prevent and treat rejection of the new organ after organ transplantation.
When are immunosuppressive drugs used?
As mentioned above, immunosuppressants are mainly used in two major areas of medicine. On the one hand, these drugs are used to prevent rejection reactions after organ transplantations, on the other hand, autoimmune diseases can be treated well with immunosuppressive drugs. Organ transplantation would never have become possible without the development of immunosuppressive drugs.
Organs can only be transplanted if the tissue characteristics of donor and recipient match as closely as possible. However, despite the fact that the tissue characteristics are as similar as possible, the body will always classify the transplanted organ as foreign and start attacking it through inflammatory reactions. Immunosuppressive drugs keep the immune system in check here and thus prevent the transplant from being rejected.
In autoimmune diseases, the immune system does not direct its defense mechanisms against foreign tissue but against its own components. Here, too, it is important to dampen the immune system so that no major tissue destruction occurs. Autoimmune diseases include ulcerative colitis, Crohn’s disease, myasthenia gravis and narcolepsy (sleep disorder).
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