Immunosuppressant
Encyclopedia
An immunosuppressant is any substance that performs immunosuppression
of the immune system
. They may be either exogenous, as immunosuppressive drug
s, or endogenous, as ,e. g., testosterone
. When the immune system function is suppressed, there is an increased susceptibility to infectious diseases and cancers.
The term immunotoxin
is also sometimes used (incorrectly) to label undesirable immunosuppressants, such as various pollutants. Polychlorinated biphenyls (PCB) and the herbicide DDT
are immunosuppressants.
After an organ transplantation, the body will nearly always reject the new organ(s) due to differences in human leukocyte antigen
haplotype
s between the donor and recipient. As a result, the immune system detects the new tissue as "hostile", and attempts to remove it by attacking it with recipient leukocytes, resulting in the death of the tissue. Immunosuppressants are applied as a countermeasure; the side-effect is that the body becomes more vulnerable to infections and malignancy, much like in an advanced HIV
infection.
Immunosuppression
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...
of the immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
. They may be either exogenous, as immunosuppressive drug
Immunosuppressive drug
Immunosuppressive drugs or immunosuppressive agents are drugs that inhibit or prevent activity of the immune system. They are used in immunosuppressive therapy to:...
s, or endogenous, as ,e. g., testosterone
Testosterone
Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...
. When the immune system function is suppressed, there is an increased susceptibility to infectious diseases and cancers.
The term immunotoxin
Immunotoxin
An immunotoxin is a human-made protein that consists of a targeting portion linked to a toxin. When the protein binds to that cell, it is taken in through endocytosis, and the toxin kills the cell...
is also sometimes used (incorrectly) to label undesirable immunosuppressants, such as various pollutants. Polychlorinated biphenyls (PCB) and the herbicide DDT
DDT
DDT is one of the most well-known synthetic insecticides. It is a chemical with a long, unique, and controversial history....
are immunosuppressants.
Uses
Immunosuppressants may be prescribed when a normal immune response is undesirable, such as in autoimmune diseases.After an organ transplantation, the body will nearly always reject the new organ(s) due to differences in human leukocyte antigen
Human leukocyte antigen
The human leukocyte antigen system is the name of the major histocompatibility complex in humans. The super locus contains a large number of genes related to immune system function in humans. This group of genes resides on chromosome 6, and encodes cell-surface antigen-presenting proteins and...
haplotype
Haplotype
A haplotype in genetics is a combination of alleles at adjacent locations on the chromosome that are transmitted together...
s between the donor and recipient. As a result, the immune system detects the new tissue as "hostile", and attempts to remove it by attacking it with recipient leukocytes, resulting in the death of the tissue. Immunosuppressants are applied as a countermeasure; the side-effect is that the body becomes more vulnerable to infections and malignancy, much like in an advanced HIV
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
infection.