D83.9: Common variable immunodeficiency, unspecified

The immune system protects the body from pathogens and foreign substances. The immune system can also destroy cells in the body that have pathologically changed. The body's immune system is made up of different types of immune cells. Some immune cells can destroy pathogens or foreign bodies themselves. Other immune cells produce certain antibodies. Some of the immune system’s antibodies can make pathogens and foreign substances visible to the immune system. Other antibodies attack pathogens or foreign substances directly.

As a result of your condition, certain immune cells are not producing enough antibodies. If you are not producing enough antibodies, you will be unable to properly combat various pathogens. Pathogens include bacteria, viruses and fungi, for example. The pathogens may then repeatedly cause infection. The infections can affect the respiratory tract, the gastrointestinal tract or the skin, for example. The infections may also be more severe and last longer than normal.

A person may also produce insufficient antibodies after certain vaccinations. You can be vaccinated against various pathogens. Vaccination is intended to help the immune system become familiar with a pathogen. After the vaccination, the immune system produces certain substances to fight the pathogens. If you come into contact with the pathogens later, the immune system can then take action against them more quickly. The pathogens are then no longer able to harm the body as much, if at all.

Moreover, parts of the immune system may also target the body's own tissue or cells. This may affect certain blood cells, skin, joints, eyes or the thyroid gland, for example.

With this condition, when the symptoms first appear and how severe they are can vary widely. As yet, the reasons behind the condition have not been fully explained.