Around the year 1900, researcher Paul Ehrlich realized that the body can distinguish between alien and endogenous cells. This vital mechanism allows the organism to recognize and destroy foreign, potentially threatening substances without destroying itself. In autoimmune diseases, this process is disturbed.
Dysfunction of the immune system
The human immune system is a complex interaction of different cells and organs, with which not only foreign substances and pathogens are recognized and destroyed, but also the body's own cells, which no longer function. Without an immune system we could not survive long - after all, we are surrounded by potentially pathogenic microorganisms such as bacteria, viruses and fungi. The defense processes can in principle be disturbed in two directions; both can lead to dysfunctions and diseases:
- Immune deficiency diseases: The defense is not effective enough, for example, in congenital immune deficiencies or when the immune system, for example, by chronic diseases or drugs is disabled.
- Autoimmune diseases: The defense works stronger than necessary and also attacks the body's own tissue.
The immune system
Our defenses are always in action: they patrol the body - especially in the form of the white blood cells and the immunoglobulins they form - in the blood and lymph vessels to detect possible dangers and destroy the creators before they can do any harm. To do this, it uses two systems: the innate, nonspecific defense and the acquired specific (or adaptive) defense that works closely together:
- Unspecific defense: These include barriers such as the skin and mucous membranes, which make it difficult to penetrate pathogens. If the enemies nevertheless stormed the barricades, various cells released messenger substances, eg so-called interleukins, which - similar to a flare rocket - signal that danger is in arrears and request help. Locally, it also causes an inflammatory reaction.
Immune quickly escalate defensive forces such as feeding and killer cells, which destroy everything that is foreign by "on-it-on strategy". In order to avoid self-targeting, the body's own healthy cells carry on their surface a kind of distinguishing mark, the so-called major histocompatibility complex (MHC). With this they can identify themselves as belonging to the body and so are spared from the destructive action. The majority of all infections are already successfully controlled by this system.
- Specific Defense: This special unit is able to target aggressors very specifically. For this she uses a kind of criminal card file, in which all the bad guys that have ever been discovered by the immune system, stored. This is stored in "memory cells". As a "fingerprint" of crooks serve antigens on their surface, which are repeatedly recognized by the antibodies (immunoglobulins), which were formed after the first contact in the body. This allows a fast, specific defense response and destroys the pathogens before they can take action.
By the way, vaccines also work according to this principle: For example, inactive (and thus harmless) viruses are injected and the body produces antibodies against its antigens (which correspond to those of the right pathogens). If the right agent enters the organism, it is quickly recognized and destroyed.