D81.4: Nezelof syndrome

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.

The thymus gland is a small organ which forms part of the immune system. The thymus gland lies below the neck and is partly surrounded by the lungs. Immune cells mature in the thymus gland. The thymus gland is at its largest in children and adolescents. Later in life, the thymus gland gradually shrinks since it is no longer required.

If the thymus gland has not developed properly, certain immune cells will be unable to mature. As a result, there will not be enough of these immune cells.

If you do not have enough antibodies, you will be unable to properly combat pathogens. This also relates to pathogens that are actually harmless to healthy people. Pathogens are bacteria, viruses and fungi, for example. When someone has a congenital immune deficiency, they usually get infected by pathogens during the first months of their life. These can cause severe illnesses such as lung inflammation and bad diarrhea. Repeated bouts of illness can severely weaken the body. As a result, babies and small children may grow more slowly and put on less weight than normal.

The disease is congenital, which means you were born with it. Other family members may also be affected.