| Immunosuppression | |
|---|---|
 Micrograph showing an opportunistic infection due to immunosuppression - large (blue) cell below-center-left infected with apolyomavirus. Urine cytology specimen. | |
| ICD-10-PCS | D89.9 |
| MeSH | D007165 |
Immunosuppression is a reduction of the activation orefficacy of theimmune system. 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.[1][2]
In general, deliberately induced immunosuppression is performed to prevent the body fromrejecting anorgan transplant.[3] Additionally, it is used for treatinggraft-versus-host disease after abone marrow transplant, or for the treatment ofauto-immune diseases such assystemic lupus erythematosus,rheumatoid arthritis,Sjögren's syndrome, orCrohn'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 aschemotherapy orHIV), is said to beimmunocompromised.[4]
Administration ofimmunosuppressive medications or immunosuppressants is the main method for deliberately inducing immunosuppression; in optimal circumstances, immunosuppressive drugs primarily target hyperactive components of the immune system.[5] People in remission from cancer who require immunosuppression are not more likely to experience a recurrence.[6] Throughout its history,radiation therapy has been used to decrease the strength of the immune system.[7] Dr. Joseph Murray of Brigham and Women's Hospital was given theNobel Prize in Physiology or Medicine in 1990 for work on immunosuppression.[8]
Immunosuppressive drugs have the potential to causeimmunodeficiency, which can increase susceptibility toopportunistic infection and decreasecancer immunosurveillance.[9] Immunosuppressants may be prescribed when a normal immune response is undesirable, such as inautoimmune diseases.[10]
Steroids were the first class of immunosuppressant drugs identified, though side-effects of early compounds limited their use. The more specific[vague]azathioprine was identified in 1960, but it was the discovery ofciclosporin in 1980 (together with azathioprine) that allowed significant expansion oftransplantation to less well-matched donor-recipient pairs as well as broad application tolung transplantation,pancreas transplantation, andheart transplantation.[3] After anorgan transplantation, the body will nearly always reject the new organ(s) due to differences inhuman leukocyte antigen 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 withwhite 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.[11][12][13]
Non-deliberate immunosuppression can occur in, for example,ataxia–telangiectasia,complement deficiencies, many types ofcancer, and certain chronic infections such ashuman immunodeficiency virus (HIV). The unwanted effect in non-deliberate immunosuppression isimmunodeficiency that results in increased susceptibility topathogens, such as bacteria and viruses.[1]
Immunodeficiency is also a potential adverse effect of manyimmunosuppressant drugs, in this sense, the scope of the termimmunosuppression in general includes both beneficial and potential adverse effects of decreasing the function of the immune system.[14]
B cell deficiency andT cell deficiency are immune impairment that individuals are born with or are acquired, which in turn can lead to immunodeficiency problems.[15]Nezelof syndrome is an example of an immunodeficiency of T-cells.[16]
{{cite journal}}:Cite journal requires|journal= (help){{cite journal}}:Cite journal requires|journal= (help){{cite journal}}:Cite journal requires|journal= (help)| International | |
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