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• AIDS HIV Terms

AIDS-HIV Related Terms

- A -

• AACTG

See Adult AIDS Clinical Trials Group.



• Acquired Immunity

See Passive Immunity.



• Acquired Immunodeficiency Syndrome (AIDS)

The most severe manifestation of infection with the Human Immunodeficiency Virus (HIV). The Centers for Disease Control and Prevention (CDC) lists numerous opportunistic infections and cancers that, in the presence of HIV infection, constitute an AIDS diagnosis. In 1993, CDC expanded the criteria for an AIDS diagnosis in adults and adolescents to include CD4+ T-cell count at or below 200 cells per microliter in the presence of HIV infection. In persons (age 5 and older) with normally functioning immune systems, CD4+ T-cell counts usually range from 500 - 1,500 cells per microliter. Persons living with AIDS often have infections of the lungs, brain, eyes, and other organs, and frequently suffer debilitating weight loss, diarrhea, and a type of cancer called Kaposi's Sarcoma. See HIV Disease; Opportunistic Infection; AIDS Wasting Syndrome.



• ACTIS

See AIDS Clinical Trials Information Service.



• Active Immunity

Protection from a disease as a result of previous exposure to the disease-causing infectious agent or antigen. The protection can be a result of having had the disease or having received a vaccine to prevent getting the disease.



• Acupuncture

A Chinese medical treatment involving the insertion of very fine sterile needles into the body at specific points according to a mapping of 'energy pathways.' Historically, acupuncture is one component of an overall program of Chinese medicine that includes theory, practice, diagnosis, physiology, and the use of herbal preparations. Acupuncture is used to control pain and to treat other conditions such as allergies or addiction withdrawal. See Alternative Medicine.



• Acute HIV Infection

The period of rapid viral replication immediately following exposure to HIV. An estimated 80 to 90 percent of individuals with primary HIV infection develop an acute syndrome characterized by flu-like symptoms of fever, malaise, lymphadenopathy, pharyngitis, headache, myalgia, and sometimes rash. Following primary infection, seroconversion and a broad HIV-1 specific immune response occur, usually within an average of 3 weeks after transmission of HIV. It was previously thought that HIV was relatively dormant during this phase. However, it is now known that during the time of primary infection, high levels of plasma HIV RNA can be documented.



• Acute HIV Infection And Early Diseases Research Program (AIEDRP)

A program funded by the National Institute of Allergy and Infectious Diseases (NIAID) focusing on innovative ways to study how HIV-1 causes disease in adults. Scientists will use interventions, such as highly active antiretroviral therapy (HAART) given in the acute and early phases of infection, to increase their understanding of the mechanisms and course of HIV disease. Information about this program can be found at



• ADAP

See AIDS Drugs Assistance Programs.



• Adenopathy

Any disease involving or causing enlargement of glandular tissues, especially one involving the lymph nodes.



• Adherence

The extent to which the patient continues the agreed-upon mode of treatment or intervention as prescribed.



• Adjuvant

An ingredient added to a prescription or solution that facilitates or modifies the action of the principal ingredient. May be used in HIV therapies or for HIV vaccines.



• Administration

(Route of Administration.) How a drug or therapy is introduced into the body. Systemic administration means that the drug goes throughout the body (usually carried in the bloodstream), and includes oral (by mouth), intravenous (injection into the vein, IV), intramuscular (injection into a muscle, IM), intrathecal (injection into the spinal canal), subcutaneous (injection beneath the skin, SQ), and rectal administrations. Local administration means that the drug is applied or introduced into the specific area affected by the disease, such as application directly onto the affected skin surface (topical administration). The effects of most therapies depend upon the ability of the drug to reach the affected area; thus the route of administration and consequent distribution of a drug in the body are important determinants of its effectiveness.



• Adult AIDS Clinical Trials Group (AACTG)

The largest HIV clinical trial organization in the world. It plays a major role in setting standards of care for HIV infection and opportunistic diseases related to HIV/AIDS in the United States and the developed world. The AACTG has been pivotal in providing the data necessary for the approval of therapeutic agents, as well as the treatment and prevention strategies, for many opportunistic infections and malignancies. The AACTG is composed of, and directed by, leading clinical scientists in HIV/AIDS therapeutic research and funded through the National Institute of Allergy and Infectious Diseases.



• Adverse Reaction

(Adverse Event.) An unwanted effect caused by the administration of drugs. Onset may be sudden or develop over time. See Side Effects.



• Aerosolized

A form of administration in which a drug, such as pentamidine, is turned into a fine spray or mist by a nebulizer and inhaled.



• AETC

See AIDS Education and Training Centers.



• Affected Community

Persons living with HIV and AIDS and other related individuals, including their families, friends, and advocates whose lives are directly influenced by HIV infection and its physical, psychological, and sociological ramifications.



• Agammaglobulinemia

A nearly total absence of immunoglobulins resulting in the loss of ability to produce immune antibodies. See Antibodies.



• Agency For Healthcare Research And Quality (AHRQ)

Provides evidence-based information on health care outcomes, quality, cost, use, and access. Information from AHRQ's research helps people make more informed decisions and improve the quality of health care services. AHRQ was formerly known as the Agency for Health Care Policy and Research. Internet address



• AHRQ

See Agency for Healthcare Research and Quality.



• AIDS

See Acquired Immunodeficiency Syndrome.



• AIDS Clinical Trials Information Service (ACTIS)

Provides quick and easy access to information on federally and privately funded clinical trials that evaluate experimental drugs and other therapies for adults and children at all stages of HIV infection. ACTIS is co-sponsored by the Food and Drug Administration, the National Institute of Allergy and Infectious Diseases, the Centers for Disease Control and Prevention, and the National Library of Medicine (see entries for these organizations). Internet address



• AIDS Dementia Complex (ADC)

(HIV-associated dementia or HAD.) A degenerative neurological condition attributed to HIV infection, characterized by a group of clinical presentations including loss of coordination, mood swings, loss of inhibitions, and widespread cognitive dysfunction. It is the most common central nervous system complication of HIV infection. Characteristically, it manifests itself after the patient develops major opportunistic infections or AIDS-related cancers. However, patients can also have this syndrome before these major systemic complications occur. The cause of ADC has not been determined exactly, but it may result from HIV infection of cells or inflammatory reactions to such infections.



• AIDS Drug Assistance Programs (ADAP)

State-based programs funded in part by Title II of the Ryan White C.A.R.E. Act that provide therapeutics (including devices necessary to administer pharmaceuticals) to treat HIV disease or prevent the serious deterioration of health, including treatment of opportunistic infections. ADAP formularies and eligibility criteria are determined state-by-state with a focus on serving low-income individuals who have limited or no coverage from private insurance or Medicaid.



• AIDS Education And Training Centers (AETC)

The Health Resources and Services Administration (HRSA) supports the National AIDS Education and Training Centers (AETCs) Program. This is a network of 15 regional centers that conduct targeted, multidisciplinary HIV education and training programs for health care providers. The mission of these centers is to increase the number of health care providers who are effectively educated and motivated to counsel, diagnose, treat, and manage individuals with HIV infection and to assist in the prevention of high risk behaviors which may lead to infection. Internet address



• AIDS Research Advisory Committee (ARAC)

A board that advises and makes recommendations to the Director, National Institute of Allergy and Infectious Diseases, on all aspects of HIV-related research, vaccine development, pathogenesis, and epidemiology.



• AIDS Service Organization (ASO)

A health association, support agency, or other service actively involved in the prevention and treatment of AIDS.



• AIDS Wasting Syndrome

The involuntary weight loss of 10 percent of baseline body weight plus either chronic diarrhea (two loose stools per day for more than 30 days) or chronic weakness and documented fever (for 30 days or more, intermittent or constant) in the absence of a concurrent illness or condition other than HIV infection that would explain the findings.



• Aidsdrugs

An online database service of the National Library of Medicine with information about drugs undergoing testing against HIV infection, AIDS, AIDS-related complex, and related opportunistic diseases. Internet address



• Aidsline

An online database service of the National Library of Medicine with citations and abstracts covering the published scientific and medical literature on AIDS and related topics. Internet address



• AIDS-Related Cancer

Several cancers are more common or more aggressive in persons living with HIV. These malignancies include certain types of immune system cancers known as lymphomas, Kaposi's Sarcoma, and anogenital cancers that primarily affect the anus and the cervix. HIV, or the immune suppression it induces, appears to play a role in the development of these cancers.



• AIDS-Related Complex (ARC)

(Early Symptomatic HIV Infection) 1. A group of common complications found in early stage HIV infection. They include progressive generalized lymphadenopathy (PGL), recurrent fever, unexplained weight loss, swollen lymph nodes, diarrhea, herpes, hairy leukoplakia, fungus infection of the mouth and throat and/or the presence of HIV antibodies. 2. Symptoms that appear to be related to infection by HIV. They include an unexplained, chronic deficiency of white blood cells (leukopenia) or a poorly functioning lymphatic system with swelling of the lymph nodes (lymphadenopathy) lasting for more than 3 months without the opportunistic infections required for a diagnosis of AIDS. See AIDS Wasting Syndrome.



• Aidstrials

An online database service of the National Library of Medicine with information about clinical trials of agents (e.g., drugs) under evaluation against HIV infection, AIDS, and related opportunistic diseases. Internet address



• Alkaline Phosphatase

An enzyme normally present in certain cells within the liver, bone, kidney, intestine, and placenta. When the cells are destroyed in those tissues, more of the enzyme leaks into the blood, and levels rise in proportion to the severity of the condition. Measurement of this enzyme is used as an indication of the health of the liver.



• Alopecia

Loss of hair that frequently occurs in patients undergoing chemotherapy for cancer or suffering from other diseases, such as AIDS, where cell-killing, or cytotoxic, drugs are used.



• Alpha Interferon (INFA)

A protein -one of three major classes of interferons-that the body produces in response to infections. In persons who are HIV positive, elevated interferon levels are regarded as an indication of disease progression. See Interferon.



• Alternative Medicine

A broad category of treatment systems (e.g., chiropractic, herbal medicine, acupuncture, homeopathy, naturopathy, and spiritual devotions) or culturally based healing traditions such as Chinese, Ayurvedic, and Christian Science. Alternative medicines share the common characteristic of non acceptance by the biomedical (i.e., mainstream Western) establishment. Alternative medicine is also referred to as 'complementary medicine.' The designation 'alternative medicine' is not equivalent to holistic medicine, a narrower term. For more information, contact the National Center for Complementary and Alternative Medicine Clearinghouse (NCCAM). Internet address



• Alveolar

Pertaining to the alveoli sacs, the site of gas exchange in the lungs.



• Amebiasis

An inflammation of the intestines caused by infestation with Entamoeba histolytica (a type of ameba) and characterized by frequent, loose stools flecked with blood and mucus.



• Amino Acids

Any of a class of nitrogen-containing acids. Some 22 amino acids are commonly found in animals and humans. Chains of amino acids synthesized by living systems are called polypeptides (up to about 50 amino acids) and proteins (more than 50 amino acids). See Peptide; Proteins.



• Anaphylactic Shock

A life-threatening allergic reaction characterized by a swelling of body tissues (including the throat) and a sudden decline in blood pressure. Symptoms include difficulty breathing, violent coughing, and chest constriction.



• Anemia

A lower than normal number of red blood cells.



• Anergy

1.The loss or weakening of the body's immunity to an irritating agent, or antigen. Patients may be so immunologically suppressed that they are unable to produce a reaction to an antigen. For example, such patients will usually not test positive for tuberculosis (TB) on a tuberculin skin test (or Mantoux test). The lack of a reaction indicates anergy. 2. Researchers in cell culture have shown that CD4+ T cells can be turned off by a signal from HIV that leaves them unable to respond to further immune system stimulation.



• Angiogenesis

The process of forming new blood vessels. Angiogenesis is essential for the growth of tumors, especially Kaposi's Sarcoma.



• Angiomatosis

A condition characterized by the formation of a tumor that is composed chiefly of blood or lymphatic vessels. See Kaposi's Sarcoma.



• Anorexia

The lack or loss of appetite that leads to significant decline in weight.



• Antenatal

Occurring before birth.



• Antibiotic

A natural or synthetic substance that inhibits the growth of micro-organisms such as bacteria or fungi. Some antibiotics are used to treat infectious diseases.



• Antibodies

Molecules in the blood or other body fluids that tag, destroy, or neutralize bacteria, viruses, or other harmful toxins (antigens). They are members of a class of proteins known as immunoglobulins, which are produced and secreted by B-lymphocytes in response to stimulation by antigens. An antibody is specific to an antigen.



• Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC)

An immune response in which antibodies bind to target cells, identifying them for attack by the immune system.



• Antibody-Mediated Immunity

Also called humoral immunity. Immunity that results from the activity of antibodies in blood and lymphoid tissue.



• Antifungal

A substance that kills or inhibits the growth of a fungus.



• Antigen

Any substance that stimulates the immune system to produce antibodies (proteins that fight antigens). Antigens are often foreign substances such as bacteria or viruses that invade the body.



• Antigen Presentation

The event of providing fragments of foreign proteins, including viruses and bacteria, to the helper T cells. The presentation occurs through the display of the fragments of foreign proteins on the surface of the antigen-presenting cells (APC).



• Antigen-Presenting Cell (APC)

The cell type that collects foreign material (e.g., antigen) and digests it into pieces that can be recognized by the immune system. The APC presents the antigen to the helper T cells, the CD4+ T cells; this results in the initiation of expansion of an immune response targeted against the foreign material. APCs are B cells, macrophages, or dendritic cells.



• Antineoplastic

A substance that prevents the development, growth, or proliferation of malignant (tumor) cells.



• Antiprotozoal

A substance that kills or inhibits the multiplication of single-celled micro-organisms called protozoa.



• Antiretroviral Drugs

Substances used to kill or inhibit the multiplication of retroviruses such as HIV.



• Antisense Drugs

An antisense, nucleic acid-related compound is the mirror image of the genetic sequence that it is supposed to inactivate. It is a synthetic segment of DNA or RNA that locks onto a strand of natural DNA or RNA with a complementary sequence of nucleotides. By binding to either the target DNA or RNA, the antisense drug prohibits the normal functioning and expression of the gene. This prevents the building of new virus particles or the infection of new host cells.



• Antitoxins

Antibodies that recognize and inactivate toxins produced by certain bacteria, plants, or animals.



• Antiviral

A substance or process that destroys a virus or suppresses its replication (i.e., reproduction).



• Aphasia

Loss of ability to speak or understand speech.



• Aphthous Ulcer

A painful oral or esophageal sore of unknown cause that has a deep eroded base. Aphthous ulcers are common in persons living with HIV.



• Apoptosis

'Cellular suicide,' also known as programmed cell death. HIV may induce apoptosis in both infected and uninfected immune system cells. Normally when CD4+ T cells mature in the thymus gland, a small proportion of these cells is unable to distinguish self from nonself. Because these cells would otherwise attack the body's own tissues, they receive a biochemical signal from other cells that results in apoptosis. See Tumor Necrosis Factor.



• Approved Drugs

In the U.S., the Food and Drug Administration (FDA) must approve a substance as a drug before it can be marketed. The approval process involves several steps, including preclinical laboratory and animal studies, clinical trials for safety and efficacy, filing of a New Drug Application (NDA) by the manufacturer of the drug, FDA review of the application, and FDA approval/rejection of application.



• ARC

See AIDS-Related Complex.



• ARM

One group of participants in a comparative clinical trial, all of whom receive the same treatment. The other arm(s) receive(s) a different treatment regimen.



• ART

Antiretroviral therapy.



• Arthralgia

A pain in a joint.



• ASO

See AIDS Service Organization.



• Aspergillosis

A fungal infection-resulting from the fungus Aspergillus-of the lungs that can spread through the blood to other organs. Symptoms include fever, chills, difficulty in breathing, and coughing up blood. If the infection reaches the brain, it may cause dementia.



• Assembly And Budding

Names for a portion of the processes by which new HIV is formed in infected host cells. Viral core proteins, enzymes, and RNA (ribonucleic acid) gather just inside the cell's membrane, while the viral envelope proteins aggregate within the membrane. An immature viral particle is formed and then pinches off from the cell, acquiring an envelope and the cellular and HIV proteins from the cell membrane. The immature viral particle then undergoes processing by an HIV enzyme called protease to become an infectious virus.



• Asymptomatic

Without symptoms. Usually used in the HIV/AIDS literature to describe a person who has a positive reaction to one of several tests for HIV antibodies but who shows no clinical symptoms of the disease.



• Ataxia

Lack of muscular coordination.



• Attenuated

Weakened or decreased. For example, an attenuated virus can no longer produce disease but might be used to produce a vaccine.



• Autoantibody

1. An antibody that is active against some of the tissues of the organism that produced it. 2. An antibody directed against the body's own tissue.



• Autoimmunization

The induction of an immune response to a body's own cells (tissue).



• Autoinoculation

Inoculation of a microorganism obtained by contact with a lesion on one's own body, producing a secondary infection.



• Autologous

Pertaining to the same organism or one of its parts; originating within an organism itself. For instance, donating your own blood for your future surgery is known as an autologous transfusion.



• Avascular Necrosis (AVN)

Also referred to as osteonecrosis. A disease resulting from temporary or permanent loss of blood supply to the bone. It is a possible late complication that may be associated with Highly Active Antiretroviral Therapy (HAART). The most common site is the femoral head. Many patients have other risk factors including alcohol abuse, hyperlipidemia, corticosteroid use, and hypercoagulability (increased clotting ability of the blood).



• AVN

See Avascular Necrosis.