In immunosuppression, the body's own defense system, the immune system, is compromised. This can be achieved specifically with drugs or triggered by disease or particular stress. Elderly people and patients with chronic diseases like cancer or diabetes also have weakened immune systems, they are immunocompromised and therefore susceptible to infectious diseases.
Immunosuppression is used in particular for organ transplants and autoimmune diseases. If the immune system is not suppressed, the new organ may be rejected. In autoimmune diseases, the immune system reacts against the patient's own body; here, immunosuppression is used as a therapy in some cases.