Immunosuppression is a reduction of the activation or efficacy of the

immune system The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as Tumor immunology, cancer cells and objects such ...

. Some portions of the immune system itself have immunosuppressive effects on other parts of the immune system, and immunosuppression may occur as an adverse reaction to treatment of other conditions. In general, deliberately induced immunosuppression is performed to prevent the body from rejecting an

organ transplant Organ transplantation is a medical procedure in which an organ (anatomy), organ is removed from one body and placed in the body of a recipient, to replace a damaged or missing organ. The donor and recipient may be at the same location, or organ ...

. Additionally, it is used for treating graft-versus-host disease after a bone marrow transplant, or for the treatment of auto-immune diseases such as

systemic lupus erythematosus Lupus, technically known as systemic lupus erythematosus (SLE), is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary among people and may be mild to severe. Comm ...

rheumatoid arthritis Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects synovial joint, joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and ...

, Sjögren's syndrome, or Crohn's disease. This is typically done using medications, but may involve surgery ( splenectomy), plasmapheresis, or radiation. A person who is undergoing immunosuppression, or whose immune system is weak for some other reasons (such as

chemotherapy Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs (chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemothe ...

HIV The human immunodeficiency viruses (HIV) are two species of '' Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the immu ...

), is said to be '' immunocompromised''.

Deliberately induced

Administration of

immunosuppressive medications Immunosuppressive drugs, also known as immunosuppressive agents, immunosuppressants and antirejection medications, are drugs that inhibit or prevent activity of the immune system. Classification Immunosuppressive drugs can be classified int ...

or immunosuppressants is the main method for deliberately inducing immunosuppression; in optimal circumstances, immunosuppressive drugs primarily target hyperactive components of the immune system. People in remission from cancer who require immunosuppression are not more likely to experience a recurrence. Throughout its history,

radiation therapy Radiation therapy or radiotherapy, often abbreviated RT, RTx, or XRT, is a therapy using ionizing radiation, generally provided as part of cancer treatment to control or kill malignant cells and normally delivered by a linear accelerator. Rad ...

has been used to decrease the strength of the immune system. Dr. Joseph Murray of Brigham and Women's Hospital was given the

Nobel Prize in Physiology or Medicine The Nobel Prize in Physiology or Medicine ( sv, Nobelpriset i fysiologi eller medicin) is awarded yearly by the Nobel Assembly at the Karolinska Institute, Nobel Assembly at the Karolinska Institute for outstanding discoveries in physiology or ...

in 1990 for work on immunosuppression. Immunosuppressive drugs have the potential to cause

immunodeficiency Immunodeficiency, also known as immunocompromisation, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that a ...

, which can increase susceptibility to opportunistic infection and decrease cancer immunosurveillance. Immunosuppressants may be prescribed when a normal immune response is undesirable, such as in autoimmune diseases. Steroids were the first class of immunosuppressant drugs identified, though side-effects of early compounds limited their use. The more specific azathioprine was identified in 1960, but it was the discovery of ciclosporin in 1980 (together with azathioprine) that allowed significant expansion of transplantation to less well-matched donor-recipient pairs as well as broad application to lung transplantation, pancreas transplantation, and heart transplantation. After an

organ transplantation Organ transplantation is a medical procedure in which an organ (anatomy), organ is removed from one body and placed in the body of a recipient, to replace a damaged or missing organ. The donor and recipient may be at the same location, or organ ...

, the body will nearly always reject the new organ(s) due to differences in

human leukocyte antigen The human leukocyte antigen (HLA) system or complex is a complex of genes on chromosome 6 in humans which encode cell-surface proteins responsible for the regulation of the immune system. The HLA system is also known as the human version of t ...

between the donor and recipient. As a result, the immune system detects the new tissue as "foreign", and attempts to remove it by attacking it with white blood cells, resulting in the death of the donated tissue. Immunosuppressants are administered in order to help prevent rejection; however, the body becomes more vulnerable to infections and malignancy during the course of such treatment.

Non-deliberate immunosuppression

Non-deliberate immunosuppression can occur in, for example, ataxia–telangiectasia, complement deficiencies, many types of

cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal bl ...

, and certain chronic infections such as human immunodeficiency virus (HIV). The unwanted effect in non-deliberate immunosuppression is

that results in increased susceptibility to

pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a ger ...

s, such as bacteria and viruses. Immunodeficiency is also a potential adverse effect of many immunosuppressant drugs, in this sense, the scope of the term ''immunosuppression'' in general includes both beneficial and potential adverse effects of decreasing the function of the immune system. B cell deficiency and

T cell A T cell is a type of lymphocyte. T cells are one of the important white blood cells of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell ...

deficiency are immune impairment that individuals are born with or are acquired, which in turn can lead to immunodeficiency problems. Nezelof syndrome is an example of an immunodeficiency of T-cells.

References

External links

PubMed
{{Medicine, state=collapsed Immune system Immunology Medical treatments it:Immunodepressione

Deliberately induced

Non-deliberate immunosuppression

See also

References

Further reading

External links