Which diseases are related to the thymus?
Rarely does a tumor appear on the thymus, a so-called thymoma. Most thymomas grow very slowly, only the malignant thymoma (thymus carcinoma) grows rapidly. As the tumor grows larger, it can increasingly press on adjacent structures such as the trachea or bronchi. Autoimmune diseases such as myasthenia gravis are often associated with thymomas. The thymus must then be removed surgically (thymectomy), which may have effects on the immune system in children that is not yet fully developed.
This autoimmune disease weakens the striated muscles. Affected are especially the eyelids and the outer eye muscles (occurrence of double images) as well as the chewing and pharyngeal muscles (chewing and swallowing disorders). It is typical that the symptoms worsen under stress. In a myasthenic crisis, the respiratory muscles may be impaired and respiratory distress may occur. It is believed that the thymus plays an important role in the development of myasthenia gravis, because it is enlarged in many people affected. In some cases, therefore, the surgical removal of the thymus positively affects the course of the disease. A thymoma can also cause myasthenia gravis by producing those autoantibodies that attack one's body.
This congenital disorder has an error on chromosome 22 or 10, respectively. In addition to eg heart defects, children with this disease have either only a weak thymus or no thymus (thymic aplasia). The T cells can not mature, so the immune system is weakened. Depending on how severe the syndrome is, the children are more susceptible to or constantly exposed to infectious diseases. In such cases, it is attempted to transfer mature T cells from a suitable donor (eg, a sibling). In America, a new form of therapy is being tested in which thymic tissue is transplanted by another human being.
Multiple sclerosis (MS) is a serious autoimmune disease in which immune cells attack and destroy healthy nerve tissue. It is based on a defect in the immune system, which is supposed to destroy only foreign cells. In fact, so-called regulatory T cells usually ensure that our immune system recognizes and spares the body's own cells. In MS patients, the thymus does not appear to be able to produce enough new regulatory T cells. This deficiency is compensated by the proliferation of older T cells, which are no longer as effective and can not prevent the attack on the body's nerve cells.