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Acquired Immune Deficiency Syndrome
(AIDS) | A disorder of
immunity characterised by abnormalities of immunoregulation and opportunistic infections. |
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| Antibody. | A component of the immune system produced in
response to exposure to antigens. Antibodies help eliminate
infectious microorganisms in the body. |
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| Antigens. | A foreign molecule that stimulates the production
of antibodies. |
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| AZT (zidovudine). | A chemotherapy drug used to slow the
progression of AIDS diseases by preventing viral replication.
Its side-effects include leucopenia, anaemia, and nausea.
Like all chemotherapy drugs, AZT is immunosuppressive. |
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| Cell-mediated immunity. | A defence mechanism involving the
coordinated activity of two subpopulations of T lymphocytes,
helper T4 cells and killer T8 cells. Helper T cells produce
substances that stimulate and regulate other cells of the
immune system. |
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| Cofactor. | A factor other than the basic causative agent of a
disease that increases the likelihood of the disease
developing. |
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| Cytomegalovirus (CMV). | A virus belonging to the herpesvirus
group, commonly associated with infections of patients who
have received medical treatment involving immune suppression.
In AIDS patients, CMV may produce pneumonia and inflammation
in various organs. |
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| Cytopathic. | Disease-induced change to cells. |
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| ELISA. | Enzyme-linked immunosorbent assay, a test used to
detect antibodies against HIV in blood samples. |
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| Encephalopathy. | Any degenerative disease of the brain. It is
a major AIDS-defining illness although it is not necessarily
caused by an infectious agent. |
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| Gay men. | A subgroup of homosexual men who identify themselves
with the gay community sharing a common identity. |
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| Haemophilia | A rare, hereditary bleeding disorder of males
due to deficiency of Factor VIII blood-clotting proteins.
Health. The state of physical and mental well-being,
characterised by the absence of disease and infirmity. |
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| Human Immunodeficiency Virus (HIV) | A nine kilobyte
retrovirus of the lentivirus family, believed to be cytopathic
of T and B lymphocytes and haematopoietic stem cells, and
associated with two types of cancer, encephalopathy, and 26
opportunistic infections. |
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| Human T-cell lymphotropic virus type III (HLTV-III) | The name
given in 1984 to isolates of the supposed AIDS-related
retrovirus, called "HIV" since 1986. The isolate was not, as
originally believed, of the HLTV family. |
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| HHV-6. | A ubiquitous virus of the herpes family proposed as a
cofactor with HIV in the aetiology of AIDS. |
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| Immune system. | A group of cells that confer protection
against infectious agents. The cells are B and T lymphocytes
and monocyte-macrophages. The products of these cells are
antibodies and lymphokines. Much of the damage caused by a
wide range of diseases is due to abnormal immune system
responses. |
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| Immunosuppression. | The diminution of immune response. |
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| Kaposi's sarcoma. | An inflammation or a cancer of the
lymphatic vessel walls, which usually appears as a violet or
brownish skin blotch. It is a major AIDS-defining disease but
it is not an infection. |
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| LAV. Lymphadenopathy-associated virus. | The name given in 1983
to the first isolate of the supposed AIDS-related virus,
called "HIV" since 1986. |
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| Lentiviruses. | A subfamily of retroviruses that includes visna
viruses of sheep and other animal viruses. |
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| Lifestyle. | The manners, habits, and consumption practices
associated with specific social roles or with personal
definitions of self. |
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| Lymphadenopathy. | Generalised swollen glands in the absence of
an illness known to cause such symptoms. |
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| Lymphocytes. | A type of white cells found in most of the
body's tissues. They stimulate production of antibodies
against infection. |
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| Mycoplasma fermentans. | A derivative of the bacterium
Mycobacterium avium-intracellulare, rarely found in humans
prior to AIDS. It has been proposed as a cofactor in immune
suppression. |
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| Nitrites ("poppers"). | A family of relaxant drugs heavily used
by gay men after 1960. Nitrites are oxidising agents that
cause cellular anoxia and impair cell-mediated immune
response. They are also mitogenic, mutagenic and
carcinogenic, and may interact with common substances, such as
antihistamines, to produce toxic N-nitroso compounds. |
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| Opportunistic infection. | An infection caused by a
microorganism that rarely induces disease in persons whose
immune systems are normal. |
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| Oxidative stress. | A disturbance of the thiol cycle of cell
metabolism leading to cell necrosis. Stress is caused by
oxidising agents, such as recreational drugs, AZT, semen,
antibiotics, and radiation therapy. Oxidative stress has been
proposed as the mechanism of the immune system damage
associated with AIDS. |
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| Provirus | A copy of the genetic information of a retrovirus
that is integrated into the DNA of an infected cell. Copies of
the provirus are passed on to each of the infected cell's
daughter cells. |
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| Retrovirus. | A family of viruses that contain the genetic
material RNA and have the capacity to copy this RNA into the
DNA of a cell. This process is called "reverse
transcription". |
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| Reverse transcriptase. | An enzyme produced by retroviruses
that allows them to produce a DNA copy of their RNA. |
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| Safer sex. | Sexual behaviour that prevents the transmission of
the HIV virus between partners. It is usually specified as
preventing the exchange of blood, semen, and vaginal
secretions. Seroconversion. The initial development of
antibodies specific to an antigen. For HIV, seroconversion is
believed to occur six to eight weeks after infection. |
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| Seropositive or HIV+. | Having antibodies to HIV in the blood.
In diseases other than AIDS, antibody response is usually
interpreted to mean that the infectious agent has been
immobilised. |
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| Syndrome. | A pattern of symptoms and signs, appearing
one-by-one or simultaneously, that together characterise a
particular disease. |
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| Syphilis | A venereal disease caused by the spirochete
Treponema pallidum and transmitted by sexual contact or in
utero. Syphilis causes lesions to the skin and organs and may
be latent for long periods. |
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| T lymphocytes (T cells) | Cells of the immune system that
originate in the thymus gland. They are found in the blood,
lymph, and lymphoid organs. |
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| T4 cells. | Helper cells of the immune system that stimulate
immune response. Also called CD4 lymphocytes. T8 (CD8) cells
"turn off" T4 cell activity. |
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| Virus. | A non-living fragment of genes that lacks motility and
metabolism and depends on the DNA of host cells for
replication. Bacteria, plants, and animals are hosts to
viruses. Virus are very small, having a mass of about one
five hundred millionth of a T cell. |
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| Western Blot. | A test that identifies antibodies against
specific protein molecules. Commonly used to confirm tests on
samples found to be reactive to the ELISA test. |
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