What is autoimmunity?
The immune defence protects cells and tissue from dangerous influences, and hence protects the organism from illnesses. However, the body’s defences can also attack the body’s own structures and then cause illnesses themselves.
This so-called autoimmunity (auto = self) may aim at almost every part of the body. The body’s immune system may either damage an organ, e. g. the liver, or it may damage the whole body. Once started, this erroneous attack continues and can damage organs completely. It is only with an effective medical therapy that this process can be stopped. Hence, early diagnosis of autoimmune diseases is vital.
Reasons for the attack of the defence system against its own body have not been detected completely. Apparently, there is an error in the coding of the immune system. Some causes for this are known: often autoimmune diseases start after an infection or in connection with the hormonal changes during pregnancy. In both cases the immune system is specially challenged and might go in the wrong direction. Furthermore, certain medication can mislead the immune system.
If, for example, a part of an infectious agent is very similar to the body’s own structure it may happen that the defence not only attacks and destroys the agent but also accidentally its own tissue. This may continue long after the initial infection has passed – the immune system has then been coded erroneously.
Lack of tolerance
It is one of the basic skills of the immune defence to distinguish between own (self) and foreign structures. Only this allows the defence reaction to limit its defence activities to the dangerous influences and save the organism itself. If this ability disappears, the own body is being attacked.
Genes also play an important role in the development of autoimmunity. Some autoimmune diseases occur more often in families. They are not passed on directly, but the inherited predisposition increases the risk of developing such a disease. In that case, if triggering environmental factors such as an infection for example influence the immune system, a false defence reaction may be caused and autoimmune disease starts.
Attacks of the immune system against the own body are the basis of a great number of diseases in almost all fields of medicine. More than 60 different autoimmune diseases can be counted among these. Often, autoimmune diseases start at an early age. Inflammatory rheumatoid arthritis, multiple sclerosis or psoriasis are well-known examples. Autoimmune liver diseases, however, are barely known to both ordinary people and doctors.
Autoimmune diseases are treated by specialists, depending on what organ or organ system is affected. However, the main principle of treatment is the same: suppression of the defence reaction of the immune system with drugs, corticosteroids for example. In order to prevent the self-destructive reaction, the whole immune system needs to be suppressed. This can be quite difficult since overtreatment can have the unwanted effect that the body’s defence becomes too weak to fight other diseases, in particular infection.
For some autoimmune diseases there are targeted therapies. For example in one of the most common autoimmune liver diseases, the primary biliary cirrhosis, a special bile acid may help to prevent liver cells from being attacked.