'Immunosuppression' involves an act that reduces the activation or efficacy of the
immune system. Some portions of the immune system itself have immuno-suppressive effects on other parts of the immune system, and immunosuppression may occur as an adverse reaction to treatment of other conditions. Deliberately induced immunosuppression is generally done to prevent the body from
rejecting an
organ transplant or for the treatment of
auto-immune diseases such as
rheumatoid arthritis or
Crohn's disease. This is typically done using drugs, but may involve surgery (splenectomy), plasmapharesis, or radiation.
A person who is undergoing immunosuppression, or whose immune system is weak for other reasons (for example,
chemotherapy and
HIV patients) are said to be ''immunocompromised''. 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.
In the past,
radiation therapy was used to decrease the strength of the immune system, but now
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
opportunistic infections, even those usually considered harmless. Also, prolonged use of immunosuppressants increases the risk of
cancer.
Cortisone was the first immunosuppressant identified, but its wide range of side effects limited its use. The more specific
azathioprine was identified in 1959, but it was the discovery of
cyclosporine in 1970 that allowed for significant expansion of
kidney transplantation to less well-matched donor-recipient pairs as well as broad application of
liver transplantation,
lung transplantation,
pancreas transplantation, and
heart transplantation.
Dr.
Joseph Murray of
Harvard Medical School and chief plastic surgeon at
Children's Hospital Boston from 1972-1985 was awarded
Nobel Prize in Physiology or Medicine in 1990 for his work on immunosuppression. Dr. Murray and his team are credited with first successful human kidney transplant at
Peter Bent Brigham Hospital, Boston on 23 December 1954.
See also
★
Immunosuppressive drug
★
Transplant rejection