Glossary of HIV/AIDS Terms
This glossary contains 1,600 terms and is maintained by the editors of the San Francisco AIDS Foundation's Bulletin of Experimental Treatments for AIDS.
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abacavir: a nucleoside reverse transcriptase inhibitor drug approved for use as part of a combination regimen to treat HIV disease.
abdomen: the area of the body between the chest and pelvis; the abdominal organs include the liver, spleen, and intestines. Compare with alkaline.
abscess: an accumulation of pus associated with a localized infection.
absorption: the passage of nutrients or drugs from the small intestine into the bloodstream.
abstract: a written summary of the important points of a scientific article.
accelerated approval: a set of FDA regulations governing early marketing approval of promising drugs for life-threatening illnesses.
acid-base balance: the normal equilibrium between acids and bases in the body. See also metabolic acidosis.
acidosis: high blood acid level (low pH). See also lactic acidosis.
acquired immune deficiency syndrome (acronym AIDS): the late stage of HIV disease; AIDS involves the loss of function of the immune system as CD4 cells are infected and destroyed, allowing the body to succumb to opportunistic diseases and cancers. The CDC defines AIDS as a CD4 cell count below 200 cells/mm3 or the presence of at least one opportunistic illness in an HIV positive individual.
ACTG: See AIDS Clinical Trials Group.
< >ACTG : See AIDS Clinical Trials Group.
active immunity: immunity naturally produced by the body's own immune system in response to stimulation by foreign antigens.
Contrast with passive immunity.
active immunization: See immunization.
activity: the immediate effect of a drug on a disease-causing microorganism. Compare with efficacy.
acupressure: a method of massage in which pressure is applied to specific acupuncture points with the fingers.
acupuncture: a traditional Chinese medicine technique that involves inserting thin needles into different acupuncture points along energy channels (meridians) on the body. The goal of acupuncture is to improve the flow of qi, the body?s vital energy; it is commonly used to manage pain and reduce addiction cravings.
acute: rapid in onset; the short-term initial stage of a disease. Contrast with chronic.
acute hepatitis: the initial stage of viral hepatitis following infection; for hepatitis C, acute hepatitis refers to the first six months of infection.
acute HIV: See primary (acute) HIV infection.
acute retroviral syndrome (acronym ARS): a combination of flu-like symptoms (e.g., fever, sore throat, skin rash, muscle or joint pain) that accompanies primary (initial) HIV infection.
ADAP: See AIDS Drug Assistance Program.
adaptive immunity: See specific immunity.
addiction: psychological and/or physiological reliance on a substance, typically characterized by cravings and compulsive use, neurochemical changes in the brain, and possibly withdrawal symptoms when the substance is stopped. See also dependence.
adefovir (brand name Hepsera): a nucleotide reverse transcriptase inhibitor that was unsuccessfully tested as an anti-HIV therapy, but is approved to treat chronic hepatitis B.
adenine: one of the purine nucleic acid bases that make up nucleotides, the building blocks of DNA and RNA.
adenopathy: enlargement of glands, especially lymph nodes (lymphadenopathy).
adherence: following a prescribed treatment regimen, including correct drug dosages, medication schedules, and food restrictions.
adipocyte: a fat cell.
adiponectin: a hormone produced by fat cells that promotes sensitivity to insulin.
adipose tissue: animal fat tissue.
adjunct therapy: therapy used in addition to a primary treatment.
adjuvant: an additive (e.g., alum, Freund’s adjuvant) in a vaccine that enhances immune response; any agent or therapy that enhances the effect of another agent or therapy.
adrenal gland: an organ located above each kidney that produces various hormones. The medulla (inner part) of the adrenal gland secretes adrenaline (epinephrine), while the cortex (outer part) secretes steroids such as cortisol and certain androgens. Reduced hormone secretion (adrenal insufficiency) can lead to fatigue, anorexia, and weight loss.
adrenaline (aka epinephrine): a hormone secreted by the medulla of the adrenal gland, particularly during physical or emotional stress. Adrenaline increases the heart rate, relaxes bronchial and intestinal smooth muscle, and accelerates certain metabolic processes. Adrenaline is used to treat severe allergic reactions and asthma.
adverse event: an unwanted reaction to therapy (e.g., rash, nausea, peripheral neuropathy, liver or kidney damage). See also side effect.
aerobic: requiring or living in the presence of oxygen; a type of exercise (e.g., running, swimming) that forces the heart and lungs to work harder to supply the muscles with oxygen.
AGCUS: atypical glandular cells of undetermined significance, a diagnosis that indicates dysplasia, or abnormal cell growth.
Agenerase: brand name of amprenavir.
agonist: an agent that binds to a receptor on a cell's surface and promotes a specific cellular activity; a drug or substance that promotes the activity of another drug. Contrast with antagonist.
AIDS: See acquired immune deficiency syndrome.
AIDS Clinical Trials Group (acronym ACTG): a NIAID-sponsored group of medical centers that evaluate treatments for HIV disease and associated illnesses. The ACTG has adult (AACTG) and pediatric (PACTG) divisions.
AIDS dementia complex (aka HIV encephalopathy): mental impairment associated with HIV disease. Symptoms may include cognitive impairment (e.g., difficulty concentrating, memory loss), disorientation, mood and personality changes, speech and vision difficulties, psychomotor dysfunction (lack of coordination) and paralysis. AIDS-related dementia typically affects people in the later stages of HIV disease.
AIDS Drug Assistance Program (acronym ADAP): a cooperative federal and state program that provides medications for HIV/AIDS and certain related conditions to individuals who otherwise could not afford them.
AIDS service organization (acronym ASO): an organization that provides care, prevention, treatment education, and/or other services to people with HIV/AIDS.
AIDS-defining illness: a condition (e.g., Pneumocystis carinii pneumonia, Kaposi's sarcoma) that is included in the CDC’s definition of AIDS.
AIDS-related complex (acronym ARC): an older term used to describe a condition in which an individual has a variety of symptoms associated with HIV disease (e.g., swollen lymph nodes, night sweats, fever, diarrhea) but does not meet the diagnostic criteria for AIDS.
AIDS-related dementia: See AIDS dementia complex.
AIN: See anal intraepithelial neoplasia.
alanine aminotransferase (aka ALT, aka SGPT): an enzyme produced by the liver. Abnormally high blood levels of ALT are released during liver inflammation, and may indicate liver disease or damage. ALT levels are monitored to gauge drug-related liver toxicity; a normal level is below about 50 IU/L.
albumin: the principal protein in blood plasma, which helps maintain the body’s fluid balance; low albumin levels are associated with malnutrition and with liver and kidney dysfunction.
alkaline: basic; having a pH greater than 7.
alkaline phosphatase (acronym AP): an enzyme found in body tissues and fluids; a high alkaline phosphatase level may indicate bone, muscle, or liver problems.
allele: a variation of a gene located at a specific location on a chromosome; each individual organism has two alleles for each trait, which may be the same (homozygous) or different (heterozygous).
allergen: an agent or substance that triggers an allergic or hypersensitivity reaction.
allergy: an immune response to an antigen (allergen) that does not normally cause an adverse reaction (e.g., animal dander, pollen). Allergic reactions are mediated by the release of histamine by mast cells. Allergic symptoms may include respiratory problems, skin rash, and anaphylactic shock.
allopathy (adjective allopathic): "Western” or conventional medicine; the medical practices used most often in the U.S.; a treatment method in which therapy induces effects different from or incompatible with the disease (e.g., using an antibiotic drug to treat a bacterial infection).
alopecia: hair loss.
alpha interferon: See interferon.
ALT: See alanine aminotransferase.
alternative therapy: therapy that is not considered standard practice in most Western countries. See also complementary and alternative medicine.
amenorrhea: absence of menstruation.
amino acid: an organic compound that is a basic structural unit of peptides and proteins. There are over 100 amino acids, eight of which (isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine) are essential for human metabolism.
aminotransferase (aka transaminase): an enzyme produced by the liver that catalyzes the transfer of amino acids. See also alanine aminotransferase. See also aspartate aminotransferase.
amphetamine (aka speed, aka upper): a psychostimulant drug that acts on the central nervous system, increasing energy and decreasing appetite. See also methamphetamine.
amplification assay: a type of test (e.g., polymerase chain reaction, branched-chain DNA) that detects and amplifies fragments of genetic material or the chemical signals they produce; such assays are used to detect microorganisms in blood and tissues.
amprenavir (brand name Agenerase): a protease inhibitor drug approved for use as part of combination antiretroviral therapy to treat HIV disease. See also fosamprenavir.
amyl nitrite: See nitrite inhalant.
amylase: an enzyme produced by the salivary glands and the pancreas that helps break down food; an elevated serum amylase level may indicate inflammation of the pancreas (pancreatitis).
anabolic steroid: a natural or synthetic hormone (e.g., testosterone, oxandrolone) that promotes the synthesis of proteins and the building of muscle mass.
anabolism: the building of proteins and muscle mass in the body. See also metabolism.
anaerobic: living in the absence of oxygen; a type of exercise (e.g., weight-lifting) that does not require increased oxygen consumption.
anal intraepithelial neoplasia (acronym AIN): abnormal growth of cells of the anal canal. See intraepithelial neoplasia. See squamous intraepithelial lesion.
analgesic: a drug or therapy that relieves pain.
analog: a compound that is similar to another in its structure and/or effects.
anaphylaxis (aka anaphylactic shock): a life-threatening allergic reaction; symptoms include swelling, difficulty breathing, and a decrease in blood pressure due to blood vessel dilation.
androgen (aka androgenic steroid): a hormone (e.g., testosterone, androsterone) or synthetic analog that has masculinizing effects, stimulating the development of the male reproductive organs and male secondary sex characteristics.
anecdotal: refers to evidence based on reports of specific individual cases rather than controlled clinical trials.
anemia: a deficiency of functional red blood cells or a low hemoglobin level, which reduces the blood’s ability to carry oxygen. Symptoms may include fatigue, weakness, shortness of breath, and heart rhythm abnormalities.
anergy (adjective anergic): absence of an immune response to a foreign antigen.
angular cheilitis: a type of oral candidiasis characterized by lesions or fissures radiating from the corners of the mouth.
anogenital: refers to the area that includes the genitals, perineum, and anus.
anorexia: loss of appetite for food.
anoscopy: examination of the anal canal using a lighted instrument to identify abnormal cell growth and, if necessary, remove a tissue sample for biopsy.
antagonist: something that works against something else; an agent that prevents the activation of a specific cellular function by binding to a cell's receptors; a drug or substance that blocks or reverses the action of another drug or chemical. Contrast with agonist.
antenatal: before birth.
anthropometrics: measurement of the human body.
antibiotic: an agent that kills or inhibits the growth of bacteria or other microorganisms.
antibody (aka immunoglobulin): a protein secreted by activated plasma cells, which evolve from B cells; antibodies are produced in response to foreign antigens as part of the body?s defense against disease. Specific antibodies bind to matching antigens; the antigen/antibody reaction forms the basis of humoral (Th2) immunity.
antibody positive: having antibodies against a microorganism, indicating previous exposure.
antibody test: an assay that detects the presence of antibodies in a blood sample. The enzyme-linked immunosorbent assay (ELISA) and the Western blot are the tests typically used to detect HIV antibodies.
anticoagulant: an agent that interferes with blood coagulation, or clotting.
antidepressant: an agent that elevates the mood and prevents or alleviates depression. The three major classes of antidepressant drugs are selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants (TCAs), and monoamine oxidase inhibitors (MAOIs); MAOIs are not widely used in people with HIV. Atypical antidepressants include bupropion (Wellbutrin), nefazodone (Serzone), and others.
antiemetic: an agent that relieves nausea and vomiting.
antifibrotic: an agent than prevents or reduces the development of liver fibrosis and cirrhosis.
antifungal: an agent that kills or inhibits the growth of fungal organisms.
antigen: any agent or substance that stimulates an immune response, including microorganisms such as bacteria or viruses.
antigen-presenting cell: a type of immune cell (e.g., macrophage, dendritic cell) that ingests and breaks up microorganisms and other foreign substances and displays pieces on its surface to stimulate an immune response.
antihistamine: an agent that inhibits the action of histamines, chemicals that mediate allergic reactions and stimulate stomach acid production.
anti-inflammatory: an agent that reduces inflammation; anti-inflammatory drugs include corticosteroids (e.g., prednisone) and non-steroidal anti-inflammatory drugs (e.g., acetaminophen).
antimicrobial: an agent that destroys or prevents the growth of microorganisms such as bacteria, fungi, or parasites.
antimycobacterial: an agent active against mycobacteria (e.g., Mycobacterium avium, Mycobacterium tuberculosis).
antineoplastic: an agent that inhibits the proliferation of cancerous cells and the growth of tumors.
antioxidant: a substance that inhibits oxidation by binding with and neutralizing free radicals and other highly reactive molecules, thereby reducing oxidative damage.
antiparasitic: a drug that kills or inactivates parasites.
antipsychotic: a drug that reduces symptoms of psychosis.
antiretroviral: an agent that suppresses the activity or replication of retroviruses such as HIV by interfering with various stages of the viral life cycle; the four approved classes are nucleoside and nucleotide reverse transcriptase inhibitors (e.g., AZT, tenofovir), non-nucleoside reverse transcriptase inhibitors (e.g., efavirenz), protease inhibitors (e.g., ritonavir), and entry inhibitors (T-20).
antiviral: any drug or other agent that interferes with the life cycle of a virus and suppresses its replication and/or pathogenic activity.
apheresis: a procedure in which whole blood is removed, specific components are filtered out, and the remainder is returned to the body.
aphthous ulcer (aka canker sore): a small, often painful shallow lesion on the mucous membranes lining the mouth, esophagus, or rectum.
apoptosis: programmed cell death.
ARC: See AIDS-related complex.
area under the curve (acronym AUC): a measure of total drug concentration in the blood plasma over a period of time. See also peak concentration. See also trough concentration.
arm: a group of participants in a clinical trial who receive the same treatment; the treatment arm receives the experimental therapy under study, while control arms receive either another type of therapy or a placebo (placebo arm).
arrhythmia: loss of normal rhythm, especially irregularities of the heartbeat.
arteriosclerosis: “hardening of the arteries”; a progressive condition in which arteries become hard and lose their elasticity. See also atherosclerosis.
arthralgia: joint pain.
arthritis: inflammation of a joint.
arthroplasty: surgical repair of a joint.
ascites: accumulation of fluid in the peritoneal (abdominal) cavity, often a sign of liver dysfunction.
ascorbic acid (aka ascorbate): See vitamin C.
ASCUS: atypical squamous cells of undetermined significance, a diagnosis that indicates dysplasia, or abnormal cell growth.
aspartate aminotransferase (aka AST, aka SGOT): an enzyme produced by the liver. Abnormally high blood levels of AST are released during liver inflammation, and may indicate liver disease or muscle damage; a normal level is below about 45 IU/L.
aspergillosis: an uncommon, life-threatening infection caused by the Aspergillus fungus; Aspergillus typically infects the lungs and sinuses, but can spread through the blood to other organs including the brain, heart, and spleen.
assay: a test, especially one used to detect the presence or concentration of a chemical marker, drug, or microorganism in the blood or other body fluids or tissues.
AST: See aspartate aminotransferase.
asthenia: weakness.
as-treated analysis: a method of analyzing the results of a clinical trial in which only participants who successfully complete a full course of treatment are analyzed. Compare with intent-to-treat (ITT) analysis.
asymptomatic: not feeling symptoms or showing signs of a disease or condition.
atazanavir (brand name Reyataz): a protease inhibitor drug approved for use as part of combination antiretroviral therapy to treat HIV disease.
atherosclerosis: narrowing and hardening of large and medium-sized arteries due to the progressive buildup of plaques on artery walls. See also arteriosclerosis.
atrophy (adjective atrophic): progressive degeneration, wasting, or decrease in size.
attenuate: to weaken or reduce the level of virulence; a live attenuated virus is a weakened strain used in a vaccine.
atypical antidepressant: an agent used to treat depression that does not belong to a major antidepressant drug class.
AUC: See area under the curve.
autoantibody: an antibody that acts against the body’s own tissues, resulting in an autoimmune response.
autoimmune response (aka autoimmunity): a condition in which an individual's immune system fails to recognize its own biochemical markers as part of the "self" and attacks body tissues as if they were foreign matter. This response can cause autoimmune diseases such as lupus and rheumatoid arthritis.
autologous: derived from the same individual; an autologous transfusion or transplant is one in which a person's own blood or tissues are removed and later reintroduced.
aviremia: lack of virus in the blood plasma.
axon: a long process of neurons that conducts neural impulses to muscles, tissues, and organs.
Ayurveda: a system of traditional medicine practiced in India.
azoles: a class of drugs (e.g., fluconazole [Diflucan], ketoconazole [Nizoral]) used to treat fungal infections.
AZT (generic name zidovudine, brand name Retrovir): a nucleoside reverse transcriptase inhibitor drug approved for use as part of combination antiretroviral therapy to treat HIV disease. Compare with bacteremia. Contrast with zoster.
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