Immunosuppression

When an organ is transplanted, the immune system of the recipient will most likely recognize it as foreign tissue and attack it. The destruction of the organ will, if untreated, end in the death of the recipient.

To prevent that, immunosuppressant drugs are used to inhibit the reaction of the immune system. The downside is that with such a deactivated immune system, the body is very vulnerable to diseases, even those usually considered harmless. Also, prolonged use of immunosuppressants increases the risk of cancer.

Immunosuppression is also used to counteract autoimmune diseases, such as rheumatoid arthritis or Crohn's disease, to prevent the immune system from attacking healthy parts of the body.