HIV Glossary of Terms
A/B/C/D/E/F/G/H/I/J/K/L/M/N/O/P/Q/R/S/T/U/V/W/X/Y/Z
AACTG: See: Adult AIDS Clinical Trials Group
Acquired Immunity: The body's ability to fight or prevent aspecific infection. This ability can be acquired either actively (byhaving and recovering from an infection or by being vaccinated againstan infection) or passively (by receiving antibodies from an outsidesource, such as breast milk or donated blood components). See Also: Active Immunity, Passive Immunity
Acquired Immunodeficiency Syndrome (AIDS): A disease of thebody's immune system caused by the human immunodeficiency virus (HIV).AIDS is characterized by the death of CD4 cells (an important part ofthe body's immune system), which leaves the body vulnerable tolife-threatening conditions, such as infections and cancers. See Also: AIDS-Defining Condition, AIDS-Related Cancer, Human Immunodeficiency Virus (HIV), Opportunistic Infection (OI)
Acquired Resistance: See: Primary Resistance
ACTG: See: AIDS Clinical Trials Group
Active Immunity: Protection from a specific infection thatdevelops after having and recovering from the infection or after beingvaccinated against the infection. See Also: Acquired Immunity
Acute HIV Infection: Also known as primary HIV infection oracute retroviral syndrome (ARS). The period of rapid HIV replicationthat occurs 2 to 4 weeks after infection by HIV. Acute HIV infection ischaracterized by a drop in CD4 cell counts and an increase in HIVlevels in the blood. Some, but not all, individuals experience flu-likesymptoms during this period of infection. These symptoms, collectivelyknown as AIDS-related complex, can include fever, inflamed lymph nodes,sore throat, and rash. These symptoms may last from a few days to 4weeks and then go away. See Also: AIDS-Related Complex (ARC)
Acute HIV Infection and Early Diseases Research Program (AIEDRP): Aprogram funded by the National Institute of Allergy and InfectiousDiseases (NIAID) to conduct research with people who have been recentlyinfected with HIV. This research is aimed at understanding how HIVinfects humans and how the disease progresses to AIDS. Scientistsbelieve that events that occur during acute and early infection maydetermine the ultimate course of the disease.
Acute Retroviral Syndrome (ARS): See: Acute HIV Infection
ADAPs: See: AIDS Drug Assistance Programs
ADC: See: AIDS Dementia Complex
Adenopathy: See: Lymphadenopathy Syndrome (LAS)
Adenovirus: A type of virus that commonly causes respiratorytract and eye infections. Adenovirus-based vaccines are being studiedas a potential way of introducing viral particles that may stimulate animmune response against HIV, thereby preventing or treating HIVinfection. See Also: Retrovirus, Preventive HIV Vaccine
Adherence: Closely following (adhering to) a prescribedtreatment regimen. Requires a patient to take the correct dose of adrug at the correct time, exactly as prescribed. Failure to adhere toan anti-HIV treatment regimen can lead to virologic failure and drugresistance. See Also: Virologic Failure, Drug Resistance
Adjuvant: Substance added to a drug that enhances or modifiesthe original drug. Also refers to a substance added to a vaccine toimprove the body's immune response to that vaccine.
ADR: See: Adverse Drug Reaction
Adult AIDS Clinical Trials Group (AACTG): A large clinicaltrial organization that conducts clinical research to test treatmentand prevention strategies for adult HIV infection and AIDS. The AACTGis funded by the National Institute of Allergy and Infectious Diseases(NIAID). See Also: Clinical Trial
Adverse Drug Reaction (ADR): Any drug effect that is unwanted,unpleasant, or potentially harmful. These effects may be mild and maydisappear when the drug is stopped or may subside as the body adjuststo the drug. Other ADRs, such as skin rashes, anemia, or organ damage,are more serious. ADRs may be assigned grades of 1 (mild) to 4(serious) to describe the strength of the reaction. See Also: Side Effect
Adverse Effect: See: Adverse Event
Adverse Event (AE): Any unfavorable and unintended sign (i.e.,an abnormal laboratory finding), symptom, or disease associated usuallyin relation to timing, with the use of a drug or other intervention,whether or not the event is considered related to this product. See Also: Adverse Drug Reaction (ADR)
AETCs: See: AIDS Education and Training Centers
Agammaglobulinemia: Absence or low levels of antibodies in the blood. This condition leaves a person vulnerable to infections. See Also: Antibody
Agency for Healthcare Research and Quality (AHRQ): An agency ofthe U.S. Department of Health and Human Services (HHS) that sponsorsand conducts research on health care results, quality, cost, use, andaccess.
AHRQ: See: Agency for Healthcare Research and Quality
AIDS: See: Acquired Immunodeficiency Syndrome
AIDS Case Definition: See: AIDS-Defining Condition
AIDS Clinical Trials Group (ACTG): A clinical trials networkthat evaluates treatments and new therapeutic approaches for thetreatment of HIV infection and opportunistic diseases related toHIV/AIDS in adults.
AIDS-Defining Condition: Any of a list of illnesses that, whenoccurring in an HIV-infected person, leads to a diagnosis of AIDS, themost serious stage of HIV infection. AIDS is also diagnosed if anHIV-infected person has a CD4 count less than 200 cells/mm3, whether ornot that person has an AIDS-defining condition. The Centers for DiseaseControl and Prevention (CDC) published a list of AIDS-definingconditions in 1993. The 26 conditions include candidiasis,cytomegalovirus disease, Kaposi's sarcoma, Mycobacterium avium complex, Pneumocystis jiroveci neumonia,recurrent pneumonia, progressive multifocal leukoencephalopathy,pulmonary tuberculosis, invasive cervical cancer, and wastingsyndrome. See Also: Acquired Immunodeficiency Syndrome (AIDS)
AIDS Dementia Complex (ADC): Also called HIV-associateddementia. A progressive mental disorder with different nervous systemeffects and mental symptoms. Mental symptoms may include memory loss;speech problems; inability to concentrate; poor judgment; or moodchanges, such as depression. Nervous system effects may includebehavior changes, such as not being able to perform daily tasks, andmotor difficulties, such as loss of control of the legs or movingslowly or stiffly. ADC is considered an AIDS-defining condition inpeople with HIV.
AIDS Drug Assistance Programs (ADAPs): Programs authorizedunder Title II of the Ryan White Comprehensive AIDS Resources Emergency(CARE) Act that operate in all 50 states, the District of Columbia,Guam, Northern Mariana Islands, Puerto Rico, and the Virgin Islands.These programs provide HIV-related prescription drugs to underinsuredand uninsured individuals living with HIV/AIDS.
AIDS Education and Training Centers (AETCs): A network of 15regional centers that conduct targeted, multidisciplinary HIV educationand training programs for health care providers. The mission of thesecenters is to increase the number of health care providers who areeducated and motivated to counsel, diagnose, treat, and manageindividuals with HIV infection and to assist in the prevention ofhigh-risk behaviors that may lead to infection. AETCs are administeredby the Health Resources and Services Administration (HRSA).
AIDS Encephalopathy: Malfunction of the brain as a result ofHIV infection. Can occur as part of acute HIV infection or can resultfrom chronic HIV infection.
AIDSinfo: A U.S. Department of Health and HumanServices (HHS) project that offers the latest federally approvedinformation on HIV/AIDS clinical research, treatment and prevention,and medical practice guidelines for people living with HIV/AIDS, theirfamilies and friends, health care providers, scientists, andresearchers. The service includes a Web site with "Live Help," atoll-free hotline (1-800-448-0440); responses to e-mail inquiries; anda variety of publications that include treatment guidelines, drug factsheets, and fact sheets based on the guidelines.http://www.aidsinfo.nih.gov
AIDS-Related Cancer: A cancer that is more common or moreaggressive in people with HIV. These cancers include certain types ofimmune system cancers (lymphomas), Kaposi's sarcoma (KS), cancers thataffect the anus and the cervix, and others. Having HIV appears to playa role in the development and progression of these cancers, althoughpeople without HIV can also have them.
AIDS-Related Complex (ARC): A group of complications thatcommonly occur in the early stage of HIV infection. These may includerecurrent fever, unexplained weight loss, swollen lymph nodes,diarrhea, herpes, or fungal infection of the mouth and throat. See Also: Acute HIV Infection
AIDS Service Organization (ASO): A health association, support agency, or other service actively involved in the prevention and treatment of HIV/AIDS.
AIEDRP: See: Acute HIV Infection and Early Diseases Research Program
Alanine Transaminase (ALT): See: Liver Function Tests
Alkaline Phosphatase: An enzyme normally present in certaincells within the liver, bone, kidney, intestine, and placenta. Whencells are destroyed in those tissues, the enzyme leaks into the blood,and levels rise in proportion to the severity of the condition.Measurement of this enzyme is one way to evaluate the health of theliver.
ALT: See: Alanine Transaminase
Amino Acid: A building block the body uses to make proteins. See Also: Protein
Anaphylaxis: Also called anaphylactic shock. A rare butlife-threatening, whole-body allergic reaction. Symptoms may appearquickly and include difficulty breathing, swelling of the throat orother parts of the body, rapid drop in blood pressure, dizziness, orunconsciousness. Anaphylaxis can be triggered by foods, drugs, insectstings, or exertion, depending on an individual's sensitivity.
Anemia: A lower than normal number of red blood cells. Symptoms may include fatigue, chest pain, or shortness of breath.
Anorexia: Lack or loss of appetite.
Antagonism: See: Drug Antagonism
Antenatal: See: Prenatal
Antepartum: The time period before childbirth (refers to the mother).
Antibiotic: A natural or man-made substance that can kill orstop the growth of micro-organisms, such as bacteria or fungi, that cancause infections.
Antibody: Also known as immunoglobulin. A protein produced bythe body's immune system to recognize and fight infectious organismsand other foreign substances that enter the body. Each antibody isspecific to a particular piece of an infectious organism or otherforeign substance. Antibodies develop after the first exposure to asubstance. See Also: Antigen
Antifungal: A natural or man-made substance that can kill or stop the growth of a fungus.
Antigen: Any substance considered foreign to the body that canstimulate the body to produce antibodies against it. Antigens includebacteria, viruses, and allergens such as pollen. See Also: Antibody
Antigen-Presenting Cell (APC): A type of cell that collectsforeign materials (antigens), digests them into small pieces, anddisplays or presents the pieces on its surface. Other cells of theimmune system recognize these pieces and become activated to fight theforeign invader. APCs include Blymphocytes, macrophages, and dendriticcells. See Also: Antigen, B Lymphocytes, Dendritic Cell, Macrophage
Antineoplastic: A natural or man-made substance that can kill or stop the growth or spread of cancer cells.
Antiprotozoal: A natural or man-made substance that can kill or stop the growth of single-celled micro-organisms called protozoa.
Antiretroviral (ARV): A drug that interferes with the ability of a retrovirus, such as HIV, to make more copies of itself. See Also: Antiretroviral Therapy (ART), Highly Active Antiretroviral Therapy (HAART) Retrovirus
Antiretroviral Pregnancy Registry: An ongoing project tocollect observational, nonexperimental information about the use ofantiretrovirals during pregnancy. Information from the registry is usedto help health care providers and patients weigh the potential risksand benefits of treatment during pregnancy. The registry does not usepatient names, and registry staff obtain information from the patients'physicians. http://www.APRegistry.com
Antiretroviral Therapy (ART): Treatment with drugs that inhibitthe ability of retroviruses, such as HIV, to multiply in the body. Theantiretroviral therapy recommended for HIV infection is referred to ashighly active antiretroviral therapy (HAART), which uses a combinationof drugs to attack HIV at different points in its life cycle. See Also: Highly Active Antiretroviral Therapy (HAART), Retrovirus
Antisense Drug: A man-made segment of DNA or RNA that can lockonto a strand of DNA or RNA from a virus or other micro-organism. Thismarks the organism's genetic instructions for destruction and preventsthe organism from making more copies of itself. See Also: Deoxyribonucleic Acid (DNA), Ribonucleic Acid (RNA)
Antiviral: A natural or man-made substance that can kill or stop the growth of a virus.
APC: See: Antigen-Presenting Cell
Aphthous Ulcer: A painful shallow sore in the mouth. The soreis usually oval shaped, with a yell ow-white center surrounded by anarrow red ring. Aphthous ulcers are 1/8- to 1/4-inch across and haveno blisters. They occur on the soft surfaces of the mouth, such as theinner cheeks, inner lips, soft areas of the roof and floor of themouth, tongue, gums, and throat.
Apoptosis: The deliberate, programmed death of a cell.Apoptosis occurs as a normal part of life and helps the body stayhealthy. If cells are damaged (for example, cancerous cells or cellsinfected with HIV), the body orders those cells to die in order tocontain the disease.
Approved Drug: In the United States, the Food and DrugAdministration (FDA) must approve a drug before it can be marketed andsold to the public. The approval process involves several steps,including laboratory and animal studies, clinical trials for safety andefficacy, filing of a New Drug Application (NDA) by the manufacturer ofthe drug, FDA review of the application, and FDA approval/rejection ofthe application. See Also: New Drug Application (NDA)
ARC: See: AIDS-Related Complex
Area Under the Curve (AUC): A measure of how much drug reachesa person's bloodstream in a given period of time (usually the timebetween each dose or within 24 hours of a dose). The AUC is calculatedby plotting the drug's blood levels on a graph at different timesduring the set period to form a curve. The area under this curvereflects the total drug exposure in the set time period.
Arm: Any of the treatment groups in a clinical trial. Mostclinical trials have two arms, but some have three or even more. Eacharm receives a different treatment or placebo. See Also: Clinical Trial, Placebo
ARS: See: Acute Retroviral Syndrome
ART: See: Antiretroviral Therapy
Arthralgia: Joint pain with additional symptoms such as heat, redness, tenderness to touch, loss of motion, or swelling.
ARV: See: Antiretroviral
ASO: See: AIDS Service Organization
Aspartate Aminotransferase (AST): See: Liver Function Tests
Aspergillosis: An infection of the lungs caused by the fungus Aspergillus.The infection may also spread through the blood to other organs.Symptoms include fever, chills, difficulty in breathing, and coughingup blood. If the infection reaches the brain, it may cause dementia.
ASTL See: Aspartate Aminotransferase
Asymptomatic: Having no obvious signs or symptoms of disease.
Ataxia: Partial or complete loss of coordination of voluntarymuscular movements. This can interfere with a person's ability to walk,talk, eat, and perform other tasks of daily living.
Atherosclerosis: A condition that results from the gradualbuildup of fatty substances, including cholesterol, on artery walls.Use of PIs may increase cholesterol levels, which increases the risk ofdeveloping atherosclerosis. However, a recent study has shown thatlong-term HAART may actually decrease the risk of therosclerosis. See Also: Cholesterol
Attachment Inhibitor: Class of anti-HIV drugs that prevents the virus from attaching to anew, healthy host cell, thus preventing cell infection. See Also: Entry Inhibitor
Attenuated: A term used to describe a bacterium or virus thathas been changed in the laboratory so that it is not harmful to people.Attenuated viruses are often used as vaccines, because they can nolonger cause disease but can still stimulate a strong immune response.Examples include the vaccines against polio (Sabin oral vaccine),measles, mumps, and rubella.
AUC: See: Area Under the Curve
Autoantibody: An antibody directed against the body's own tissue. See Also: Antibody
Avascular Necrosis (AVN): Death of bone (also known asosteonecrosis) caused by a loss of blood supply to the bone tissue. AVNhas occurred in the hip bones of some people with HIV, but it is notclear if bone death occurs because of HIV infection itself or as a sideeffect of anti-HIV drugs. Symptoms include pain in the affected area ofthe body, limited range of motion, joint stiffness, limping, and musclespasms. If untreated, AVN can cause progressive bone damage that leadsto bone collapse. See Also: Osteonecrosis
AVN: See: Avascular Necrosis
B2M: See: Beta-2 Microglobulin
Bactericide: A natural or man-made substance that kills bacteria.
Bacteriostatic: A natural or man-made substance that can prevent bacteria from reproducing but cannot actually kill existing bacteria.
Bacterium: A microscopic organism consisting of one simplecell. Bacteria occur naturally almost everywhere on earth, including insoil, on skin, in the human gastrointestinal tract, and in many foods.Some bacteria can cause disease in humans.
Baseline: An initial measurement (for example, CD4 count orviral load) made before starting treatment or therapy for a disease orcondition. In people infected with HIV, the baseline measurement isused as a reference point to monitor HIV infection.
Basophil: An infection-fighting white blood cell that causes inflammation in response to a micro-organism or other foreign invader.
B Cell: See: B Lymphocyte
B-Cell Lymphoma: A type of cancer of the lymphatic tissue.People with HIV are more prone to non-Hodgkin's and other B-celllymphomas, some of which are considered AIDS-defining conditions inpeople with HIV. See Also: Lymphoma, Non-Hodgkin's Lymphoma (NHL)
bDNA Assay: See: Branched-Chain DNA Assay
Beta-2 Microglobulin (B2M): A protein found on the surface ofwhite blood cells. Increased production or destruction of white bloodcells causes B2M levels in the blood to increase. This increase is seenin people with cancers involving white blood cells and in people withadvanced HIV disease.
b.i.d.: Twice-a-day dosing instructions.
Bilirubin: A yellowish substance excreted by the liver. Itsmeasurement can be used as an indication of the health of the liver.Large quantities of bilirubin may cause the skin to take on a yellowtint (jaundice), and very high levels may cause brain damage. See Also: Jaundice
Bioavailability: Rate and extent to which a drug is absorbed and available in the tissues of the body.
Biological Response Modifier (BRM): A natural or man-made substance that can boost, direct, or restore immune system function.
Biopsy: The surgical removal and examination of an organ or tissue to aid in diagnosis and treatment of a health condition.
Black Box Warning: Information found at the beginning of adrug's prescribing information, manufacturer labeling, and promotionalmaterial. This information highlights important safety information,such as serious side effects, drug interactions, or use restrictions.The black box warning is one of the strongest warnings issued by theFood and Drug Administration (FDA) and is reserved for drugs withsignificant risks or monitoring requirements. See Also: Package Insert
Blip: A temporary increase in viral load in someone whopreviously had undetectable virus and who later returns to havingundetectable virus. The viral load during a blip is usually low (50 to500 copies/mL). See Also: Undetectable Viral Load (UDVL)
Blood-Brain Barrier: A selective obstacle between circulatingblood and brain tissues that prevents damaging substances from reachingthe brain. Certain substances easily cross the blood-brain barrier;others are completely blocked.
B Lymphocyte: Also known as a B cell. Infection-fighting whiteblood cell that develops in the bone marrow and spleen. B lymphocytesproduce antibodies. In people with HIV, the ability of B lymphocytes todo their job may be damaged. See Also: Antibody
Body Habitus Changes: Abnormal changes in the body's physical characteristics. See Also: Wasting Syndrome, Lipoatrophy, Lipohypertrophy
Bone Marrow Suppression: See: Myelosuppression
Booster: An additional dose or doses of a vaccine given afterthe initial dose to enhance the immune response to the vaccine. Alsoused as a term to describe a medicine given to enhance anothermedicine, such as using ritonavir (RTV) as a booster with other PIs.
Branched-Chain DNA (bDNA) Assay: A test that measures aperson's viral load (level of HIV RNA in the blood) to identify HIVinfection and to monitor disease progression and treatmenteffectiveness. Results are reported as the number of HIV RNA copies permilliliter of blood. bDNA assay is an alternative to measuring viralload by reverse transcriptase-polymerase chain reaction (RT-PCR). See Also: Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR), Viral Load (VL)
BRM: See: Biological Response Modifier
Bronchoscopy: Visual examination of the bronchial passages ofthe lungs using an endoscope (a curved, flexible tube containing fibersthat carry light down the tube and project an enlarged image of thebronchial passages onto a viewing screen). Can also be used forextraction of material from the lungs.
Budding: The final step in the HIV life cycle, in which anindividual virus pushes out (or "buds") from the host cell, steals partof the cell's outer envelope, and frees itself to attach to and infectanother host cell.
Buffalo Hump: See: Dorsocervical Fat Pad, See Also: Body Habitus Changes
Burkitt's Lymphoma: Also known as small, noncleaved-celllymphoma. A type of non-Hodgkin's lymphoma. There are three types ofBurkitt's lymphoma, one type occurs in people with weakened immunesystems, such as those with AIDS. See Also: Non-Hodgkin's Lymphoma (NHL)
Cachexia: Loss of weight, muscle wasting, fatigue, weakness,and decrease of appetite in someone who is not actively trying to loseweight. Usually associated with serious disease.
CAM: See: Complementary and Alternative Medicine
Candidiasis: Infection caused by a species of the yeast-like fungus Candida, usually C. albicans.Candidiasis can affect the skin; nails; and mucous membranes throughoutthe body, including the mouth (thrush), esophagus, vagina, intestines,and lungs. The infection appears as white patches when in the mouth orany other mucous membrane. Candidiasis is considered an AIDS-definingcondition in people with HIV.
Cardiomyopathy: A condition that weakens the heart muscle orcauses a change in heart muscle structure. Cardiomyopathy is associatedwith inadequate heart pumping or other heart function abnormalities.Cardiomyopathy may occur in HIV-infected people with advanced disease.Irregular heartbeat, abnormal heart and breath sounds, decreased heartfunction, or heart enlargement may indicate cardiomyopathy.
CARE Act: See: Ryan White CARE Act
CBC: See: Complete Blood Count
CBO: See: Community-Based Organization
CCR5: Chemokine receptor 5 (CCR5) is a protein on the surfaceof some immune system cells. It is one of two co-receptors that HIV canuse along with the CD4 receptor to bind to and enter host cells. (Theother co-receptor is CXCR4.) See Also: Co-receptor CXCR4, CD4 Receptor, CCR5 Receptor Blocker
CCR5 Receptor Blocker: Class of anti-HIV drug that stops HIVfrom binding to the CCR5 coreceptor, a receptor that most strains ofHIV need to enter cells. Without the ability to bind to CCR5, HIVentry is halted. See Also: CCR5 Co-receptor
CD4 Cell: Also known as helper T cell or CD4 lymphocyte. A typeof infection fighting white blood cell that carries the CD4 receptor onits surface. CD4 cells coordinate the immune response, which signalsother cells in the immune system to perform their special functions.The number of CD4 cells in a sample of blood is an indicator of thehealth of the immune system. HIV infects and kills CD4 cells, whichleads to a weakened immune system. See Also: CD4 Cell Count, CD4 Receptor
CD4 Cell Count: A measurement of the number of CD4 cells in asample of blood. The CD4 count is one of the most useful indicators ofthe health of the immune system and the progression of HIV/AIDS. A CD4cell count is used by health care providers to determine when to begin,interrupt, or halt anti-HIV therapy; when to give preventive treatmentfor opportunistic infections; and to measure response to treatment. Anormal CD4 cell count is between 500 and 1,400 cells/mm3 of blood, butan individual's CD4 count can vary. In HIV-infected individuals, a CD4count at or below 200 cells/mm3 is considered an AIDS-definingcondition. See Also: CD4 Cell
CD4 Percentage: The percent of lymphocytes (white blood cells)that are CD4 cells. This measurement is less likely to vary in betweenblood tests than CD4 count, but CD4 count remains a more reliablemeasure of immune function than CD4 percentage for most people. See Also: CD4 Cell Count, CD4 Cell
CD4 Receptor: A specific molecule present on the surface of aCD4 cell. HIV recognizes and binds to a CD4 receptor and a co-receptorto gain entry into a host cell. See Also: CD4 Cell Co-receptor
CD8 Cell: Also called a cytotoxic T lymphocyte (CTL), killer Tcell, or suppressor T cell. A type of white blood cell that is able toidentify and kill cells infected with bacteria, viruses, or otherforeign invaders.
CDC: See: Centers for Disease Control and Prevention
CDCINFO: A service sponsored by the Centers for Disease Controland Prevention (CDC) to provide referrals, education, and informationabout topics including HIV/AIDS, other sexually transmitted diseases(STDs), immunizations, and disease outbreaks. The CDCINFO hotlinenumber is 1-800-CDCINFO (232-4636).
Cell-Mediated Immunity: Immune protection provided by thedirect action of immune cells. With this type of immune protection,the response to infectious micro-organisms is performed by specificcells-such as CD8 cells, macrophages, and other white bloodcells-rather than by antibodies. The main role of cell-mediatedimmunity is to fight viral infections. See Also: Macrophage, Antibody, Immune Response
Cellular Immunity: See: Cell-Mediated Immunity
Centers for Disease Control and Prevention (CDC): An agency ofthe U.S. Department of Health and Human Services (HHS) that is chargedwith protecting the health and safety of citizens at home and abroad.The CDC serves as the national focus for developing and applyingdisease prevention and control, environmental health, and healthpromotion and education activities designed to improve the health ofthe people of the United States. http://www.cdc.gov
Centers for Medicare and Medicaid Services (CMS): Previouslyknown as the Health Care Financing Administration (HCFA). An agency ofthe U.S. Department of Health and Human Services (HHS) responsible foradministering Medicare, Medicaid, State Children's Health InsuranceProgram (SCHIP), Health Insurance Portability and Accountability Act(HIPAA), Clinical Laboratory Improvement Amendments (CLIA), and otherhealth related programs.
Central Nervous System (CNS): The part of the nervous systemmade up of the brain, spinal cord, and spinal nerves. These serve asthe main processing center for the whole nervous system and togethercontrol all the workings of the body. HIV can infect and damage partsof the central nervous system.
Cerebrospinal Fluid (CSF): A clear, colorless fluid that fillsthe spaces in the brain and the central canal of the spinal cord aswell as the spaces between nerve cells.
Cervical Cancer: A condition in which a cancerous growth (also called a malignancy) develops on the lower portion of the uterus (cervix). See Also: Cervical Dysplasia, Pap Smear, Human Papillomavirus (HPV).
Cervical Dysplasia: The abnormal growth of cervical cells,usually with no symptoms. It can be detected by a Pap smear, andtreatment can prevent it from progressing to cervical cancer. See Also: Cervical Cancer, Pap Smear, Human Papillomavirus (HPV)
Cervical Intraepithelial Neoplasia (CIN): A general term forthe growth of abnormal cells on the surface of the cervix. Numbers from1 to 3 may be used to describe how much of the cervix contains abnormalcells. See Also: Cervical Dysplasia
Cervix: The lower, narrow end of the uterus that forms a canal between the uterus and vagina.
Chancroid: A sexually transmitted disease (STD) caused by a bacterium called Hemophilus ducreyi.Often causes swollen lymph nodes and painful sores on the penis,vagina, or anus. The lesions appear after an incubation period of 3 to5 days and may facilitate HIV transmission.
Chemical Barrier: A mechanism that uses chemicals to try toprevent sexually transmitted infections (STIs), including HIVinfection. Microbicides are currently being studied as chemicalbarriers to prevent the transmission of STIs. See Also: Microbicide
Chemokines: Proteins that serve as chemical messengers tocontrol the activities of the immune system. Chemokines are involved ina wide variety of processes, including the control of infectiousdiseases, cancers, and inflammation. Chemokines include interferons,interleukins, and many other small proteins.
Chemoprevention: Also known as chemoprophylaxis. The use ofnatural or man-made agents to help reduce the risk of or delay thedevelopment or recurrence of a disease, such as cancer.
Chemoprophylaxis: See: Chemoprevention
Chemotherapy: Treatment with anticancer drugs that kill orprevent the growth and division of cells. The drugs enter thebloodstream and travel through the body killing mostly cancer cells,but some healthy cells may be killed as well.
Chlamydia: A sexually transmitted disease (STD) caused by a bacterium called Chlamydia trachomatis.The bacteria infect the genital tract and, if left untreated, can causedamage to the female and male reproductive systems, resulting ininfertility.
Cholesterol: A fat-like substance used as a building block forcells. Cholesterol is both made by the liver and absorbed from food andis carried in the blood. When blood cholesterol levels are too high(hyperlipidemia), some of the cholesterol is deposited on the walls ofthe blood vessels, increasing the risk of heart disease andatherosclerosis. Use of PIs may also increase cholesterol levels. See Also: Hyperlipidemia
Chronic Idiopathic Demyelinating Polyneuropathy (CIPD): Chronic,spontaneous loss or destruction of myelin, a white fatty material thatprotects and insulates nerve cells. People with CIPD show progressive,usually symmetrical weakness in the arms and legs. CIPD can be one ofthe symptoms of lactic acidosis or progressive multifocalleukoencephalopathy. See Also: Lactic Acidosis, Progressive Multifocal Leukoencephalopathy (PML).
CIN: See: Cervical Intraepithelial Neoplasia
CIPD: See: Chronic Idiopathic Demyelinating Polyneuropathy
CIPRA: See: Comprehensive International Program of Research on AIDS
Clade: A group of organisms that are genetically similar anddescended from a single parent organism. With HIV, the term claderefers to a group of specific HIV-1 strains within an HIV subtype. Forexample, HIV-1 subtype M contains clades A through H, J, and K. CladesB and C account for the majority of HIV infections around the world. See Also: Subtype
Class-Sparing Regimen: An anti-HIV drug regimen thatpurposefully does not include one or more classes of anti-HIV drugs. Aclass-sparing regimen may be prescribed to save certain classes ofdrugs for later use or to avoid side effects specific to a class. Forexample, a PI-sparing regimen would not include any PIs. Because somePIs may cause an increase in cholesterol in the blood, a PI-sparingregimen might be prescribed for an HIV-infected person who already hashigh cholesterol levels.
Clinical Alert: The National Institutes of Health (NIH)publishes these electronic bulletins containing urgent early results ofclinical trials. The data in these bulletins warn about possiblemorbidity (sickness rates) and mortality (death rates) in participantsinvolved in the clinical trials.
Clinical Endpoint: A measurement used in clinical trials toevaluate the effect of the treatment being tested. Examples of clinicalendpoints for HIV disease include death, serious drug toxicity, ordevelopment of an AIDS-defining illness. Because these endpoints may bedifficult to measure without long-term follow-up, surrogate(substitute) short-term endpoints, such as a change in viral load orCD4 count, may also be used as clinical endpoints. See Also: Clinical Trial
Clinical Failure: The occurrence or recurrence of HIV-relatedinfections or a decline in physical health despite taking an HIVtreatment regimen for a minimum of 3 months. Clinical failure may occuras a result of virologic or immunologic failure. See Also: Virologic Failure, Immunologic Failure
Clinical Practice Guidelines: Recommendations by panels ofexpert health care practitioners designed to assist clinicians andpatients in making decisions about appropriate health care for specificdiseases and conditions.
Clinical Progression: A term for the overall progression of adisease as measured by deterioration of clinical outcomes. In anHIV-infected person, clinical progression may be defined as theoccurrence or recurrence of HIV related events (after at least 3 monthson an antiretroviral regimen), excluding immune reconstitutionsyndromes. HIV-infected patients who have a CD4 T-cell count less than100 cells/mm3 are considered to have a high likelihood of clinicalprogression.
Clinical Trial: A research study that uses human volunteers toanswer specific health questions. Carefully conducted clinical trialsare regarded as the fastest and safest way to find effective treatmentsfor diseases and conditions as well as other ways to improve health.Interventional trials use controlled conditions to determine whetherexperimental treatments or new ways of using known treatments are safeand effective. Observational trials gather information about healthissues from groups of people in their natural settings. Clinical trialsmay be prospective (studying data from a time point forward) orretrospective (studying data from collected records in the past).
ClinicalTrials.gov: An online, searchable database ofinformation about clinical trials sponsored by governments,pharmaceutical companies, and other organizations. This database ismanaged by the National Institutes of Health (NIH) through its NationalLibrary of Medicine (NLM). http://www.clinicaltrials.gov/ See Also: Clinical Trial
CMAX: Also called maximum concentration. The maximum (peak) amount of drug measurable in the blood after a dose is administered. See Also: CMIN
CMIN: Also called minimum concentration. The lowest (trough) amount of drug measurable in the blood after a dose is administered. See Also: CMAX
CMS: See: Centers for Medicare and Medicaid Services
CMV: See: Cytomegalovirus
CMV Retinitis: See: Cytomegalovirus Retinitis
CNS: See: Central Nervous System
Coccidioidomycosis: Also called desert fever, San JoaquinValley fever, or valley fever. An infectious disease caused by theinhalation of spores of Coccidioides immitis. The disease isespecially common in hot, dry regions of the Southwestern United Statesand Central and South America. It is an AIDS-defining condition inpeople with HIV. See Also: AIDS-Defining Condition
Cognitive Impairment: Loss of the ability to process, learn,and remember information. The progression of HIV disease may lead tocognitive impairment. See Also: AIDS Dementia Complex
Cohort: A group of individuals who are alike in some way. Forexample, the people in a cohort of HIV-infected individuals are allinfected with HIV.
Coinfection: Infection with more than one virus, bacterium, orother microorganism at a given time. For example, an HIV-infectedindividual may be coinfected with hepatitis C virus (HCV) ortuberculosis (TB).
Colitis: Inflammation of the colon (large intestine). This maylead to intestinal bleeding, ulcers, or perforations (holes) in thecolon.
Combination Therapy: Two or more drugs used together to achieveoptimal results in controlling HIV infection. Combination therapy hasproven more effective in decreasing viral load than monotherapy(single-drug therapy), which is no longer recommended for the treatmentof HIV. An example of combination therapy is the use of two NRTIs plusa PI or an NNRTI.
Community-Based Organization (CBO): A service organization thatprovides social services to local clients. CBOs include nonprofitorganizations and free clinics targeted at helping people with HIV.
Community Programs for Clinical Research on AIDS (CPCRA): Alsoknown as the Terry Beirn Community Programs for Clinical Research onAIDS. A network of clinical research units composed of community-basedhealth care providers. CPCRA's aim is to serve populationsunder-represented in previous clinical trials. CPCRA is funded by theNational Institute of Allergy and Infectious Diseases (NIAID).
Comorbid Condition: Any disease or condition that occurs at thesame time as another disease or condition. The second disease mayworsen or be worsened by the initial disease. For example, tuberculosis(TB) may occur as a co-morbid condition in an individual infected withHIV, and the HIV infection may worsen the TB.
Compassionate Use: General term used to describe any programthat provides an experimental therapy outside of clinical trials topatients who do not have any FDA-approved treatment options (forexample, HIV-infected individuals who have extensive drug resistance toapproved anti-HIV drugs). To enroll in compassionate use programs, anindividual has to meet strict medical criteria. See Also: Expanded Access Investigational Drug
Complementary and Alternative Medicine (CAM): Health carepractices not currently considered part of conventional medicine. Atherapy is called complementary when it is used in addition toconventional treatments. It is called alternative when it is usedinstead of conventional treatment. CAM includes a broad range ofhealing therapies, approaches, and systems. Some examples of CAM areacupuncture, herbs, homeopathy, chiropractic, hypnosis, and traditionalChinese medicine.
Complete Blood Count (CBC): A general blood test that measuresthe levels of white and red blood cells, platelets, hematocrit, andhemoglobin in a sample of blood. Changes in the amounts of each ofthese may indicate infection, anemia, or other health problems.
Comprehensive International Program of Research on AIDS (CIPRA): Aprogram administered by the National Institute of Allergy andInfectious Diseases (NIAID) to support research and development ofpractical, affordable, and acceptable methods to prevent and treatHIV/AIDS in resource-poor countries.
Concentration: The relative amount of a substance, such as anadministered drug or a circulating enzyme, found in a particularlocation, such as the blood or a specific organ. For example, drugconcentrations are often reported as the amount of drug in a measuredsample of blood. See Also: CMIN, CMAX
Condyloma Acuminatum: See: Genital Warts
Contagious: Easily passable between people through normalday-to-day contact. For example, chicken pox is both an infectious(causing infection) and a contagious disease. In contrast, HIV is anexample of an infectious disease that is not a contagious disease(i.e., it cannot be passed from person to person through casualcontact).
Contraindication: A specific situation in which a particulartreatment should NOT be used, because it may be harmful to the patient.For example, some anti-HIV drugs are primarily broken down by the liverand should not be given to people who have liver damage.
Controlled Trial: A control is a standard against whichexperimental treatments may be compared and evaluated for safety andeffectiveness. In clinical trials, one group of patients may be givenan experimental drug, while another group (the control group) is giveneither a standard treatment for the disease or a placebo. See Also: Placebo
Core: The inner protective coat of protein that surrounds thegenetic material of most viruses. In HIV, the core is mostly made up ofthe p24 protein, which surrounds two copies of HIV's genetic material.
Coreceptor: A protein on the surface of a cell that serves as asecond binding site for a virus or other molecule. Although the CD4protein is HIV's primary receptor, the virus must also bind to eitherthe CCR5 or CXCR4 coreceptor to get into a host cell. See Also: CCR5, CXCR4, CD4 Receptor
CPCRA: See: Community Programs for Clinical Research on AIDS
Creatinine: A protein found in muscles and blood and excretedby the kidneys into the urine. The level of creatinine in the blood orurine provides a measure of kidney function. Increased levels ofcreatinine indicate abnormal or impaired kidney function.
Cross Resistance: Cross resistance occurs when a micro-organismhas changed, or mutated, in such a way that it loses its susceptibilityto multiple drugs simultaneously. For example, HIV resistance to oneNNRTI drug usually produces resistance to the entire NNRTI drug class. See Also: Drug Resistance, Non-Nucleoside Reverse Transcriptase Inhibitor (NNRTI), Mutation
Cross Sensitivity: A drug reaction that may occur again withthe use of a different, but related, drug. Cross sensitivity can occurwithin a drug class, such as when a person reacts to all NNRTIssimilarly after treatment with just one. Cross sensitivity can alsooccur among chemically similar drug classes. For example, a person whohas a negative side effect to a sulfa-based antibiotic is at risk forthe same negative side effect if he or she takes any other sulfa-baseddrug.
Cryotherapy: The use of liquid nitrogen to freeze and destroy alesion or growth to prevent further spread of the growth. In peoplewith HIV, it is used to treat lesions caused by Kaposi's sarcoma (KS)and condyloma acuminatum (genital warts). See Also: Genital Warts, Kaposi's Sarcoma (KS)
Cryptococcal Meningitis: A life-threatening infection of the membranes surrounding the brain and the spinal cord caused by the fungus Cryptococcus neoformans.Symptoms include headache, dizziness, stiff neck, and-if untreated-comaand death. Immunocompromised individuals, such as those with HIV, aremore susceptible to this infection. It is considered an AIDS-definingcondition in people with HIV.
Cryptococcosis: An infection caused by the fungus Cryptococcusneoformans. This fungus typically enters the body through the lungsand usually spreads to the brain, causing cryptococcal meningitis. Insome cases, it can also affect the skin, skeletal system, and urinarytract. It is considered an AIDS defining condition in people withHIV. See Also: Cryptococcal Meningitis
Cryptosporidiosis: A diarrheal disease caused by the protozoa Cryptosporidium. Symptoms include abdominal cramps and severe chronic diarrhea. It isconsidered an AIDS-defining condition in people with HIV. See Also: Cryptosporidium
Cryptosporidium: The protozoan that causescryptosporidiosis. It is found in the intestines of animals and may betransmitted to humans by direct contact with an infected animal, byeating contaminated food, or by drinking contaminated water. See Also: Cryptosporidiosis
CSF: See: Cerebrospinal Fluid
CTL: See: Cytotoxic T Lymphocyte
Cutaneous: Of, relating to, or affecting the skin.
CXCR4: Chemokine receptor 4 (CXCR4, also known as fusin) is aprotein on the surface of some immune system cells. It is one of twoco-receptors that HIV can use along with the CD4 receptor to bind toand enter host cells. (The other co-receptor is CCR5.) See Also: Co-receptor, CD4 Receptor, CCR5
CYP450: See: Cytochrome P450
Cytochrome P450 (CYP450): A system of enzymes, locatedprimarily in the liver, that participates in the breakdown of drugs.Many drugs inhibit or enhance the activity of these enzymes. Any changein CYP450 enzyme activity may cause an increase or decrease in bloodlevels of drugs that are broken down through this system. See Also: Drug Interaction
Cytokine: A protein produced by white blood cells that acts as achemical messenger between cells. Cytokines can stimulate or inhibitgrowth or activity of immune cells and are essential for a coordinatedimmune response. Cytokines include the interleukins and theinterferons. See Also: Interleukin (IL-2, IL- 7), Interferon (IFN)
Cytomegalovirus (CMV): A herpesvirus that can cause infections,including pneumonia (infection of the lungs), gastroenteritis(infection of the gastrointestinal tract), encephalitis (inflammationof the brain), or retinitis (infection of the eye), in immunosuppressedpeople. Although CMV can infect most organs of the body, HIV-infectedpeople are most susceptible to CMV retinitis. See Also: Cytomegalovirus Retinitis, Herpesviruses
Cytomegalovirus Retinitis: An infectious eye disease caused bycytomegalovirus (CMV). People with CMV retinitis can lose their vision,and CMV retinitis is the most common cause of blindness among peopleinfected with HIV. See Also: Cytomegalovirus (CMV)
Cytopenia: A condition in which the production of one or morekind of blood cells is greatly reduced or stops completely. Some drugsused to treat HIV or cancer may cause cytopenia.
Cytotoxic: Toxic or destructive to cells. For example, cancerchemotherapy is cytotoxic, because it destroys both cancerous andnon-cancerous cells.
Cytotoxic T Lymphocyte (CTL): See: CD8 Cell
DAART: See: Directly Administered Antiretroviral Therapy
DAIDS: See: Division of Acquired Immunodeficiency Syndrome
Data and Safety Monitoring Board (DSMB): An independentcommittee of community representatives and clinical research expertswho review data while a clinical trial is in progress to ensure thatparticipants are not exposed to undue risk. A DSMB may recommend that atrial be stopped if there are safety concerns or if the trialobjectives have been achieved, or the DSMB can require changes to thestudy design to ensure safety of participants.
Dementia: See: AIDS Dementia Complex (ADC)
Dendritic Cell: A type of antigen-presenting cell that picks upforeign substances from the bloodstream and presents them to otherparts of the immune system, which activates an immune response againstthe
foreign invader. See Also: Antigen-Presenting Cell (APC), Antigen
Dendritic Cell Vaccine: Vaccine made of antigens and dendriticantigen-presenting cells. Dendritic cell vaccines are being studied aspossible therapeutic HIV vaccines to treat HIV-infected people. See Also: Therapeutic HIV Vaccine, Dendritic Cell
Deoxyribonucleic Acid (DNA): Chemical structure that containsthe genetic instructions for reproduction and protein synthesis for allcells and for many viruses.
Department of Health and Human Services (HHS): The U.S.government's principal agency for protecting the health of allAmericans and for providing essential human services. HHS includes morethan 300 programs that cover a wide spectrum of activities. More than300 programs are administered by 11 operating divisions, including theCenters for Disease Control and Prevention (CDC), the Food and DrugAdministration (FDA), and the National Institutes of Health (NIH). HHSworks closely with state and
local governments, and many HHS-funded services are provided at thelocal level by state or county agencies or through private-sectorgrantees. http://www.hhs.gov/
Desensitization: A gradual increase in the dose of a medicineto avoid severe side effects. Desensitization procedures are sometimesused when administering some anti-HIV drugs and antibiotics.
DEXA: See: Dual Energy X-Ray Absorptiometry Scan
Diabetes: Also known as diabetes mellitus. A diseasecharacterized by high levels of sugar in the blood (hyperglycemia). Itcan be caused by too little insulin (a hormone produced by the pancreasto regulate blood sugar), resistance to insulin, or both. Some anti-HIVdrugs may cause or worsen diabetes.
See Also: Hyperglycemia, Insulin Resistance
Diarrhea: Uncontrolled, loose, watery, and frequent bowelmovements caused by diet, infection, drug, or irritation orinflammation of the intestine. Severe or long-lasting diarrhea canlead to weight loss and
malnutrition. The most common infectious organisms that cause HIV-related diarrhea include cytomegalovirus (CMV); the parasites Cryptosporidium, Microsporidia, and Giardia; and the bacteria
Mycobacterium avium and Mycobacterium intracellulare.Bacteria and parasites that cause diarrheal symptoms in otherwisehealthy people may cause more severe, prolonged, or recurrent diarrhea
in people with HIV or AIDS.
Directly Administered Antiretroviral Therapy (DAART): Method ofensuring that a person takes anti-HIV drugs as prescribed. DAARTrequires that a caregiver directly observe the patient ingest theanti-HIV drugs to increase adherence to the treatment plan. See Also: Adherence, Directly Observed Therapy (DOT)
Directly Observed Therapy (DOT): A treatment strategy to ensureadherence, in which a health care provider or other observer watches apatient take each dose of a drug. This strategy is used with diseaseslike tuberculosis (TB) and HIV infection, in which adherence isimportant for effective treatment
and to prevent emergence of drug resistance. See Also: Adherence
Discordant Couple: A pair of long-term sexual partners in whichone person is infected with a sexually transmitted infection (such asHIV) and the other is not.
Disseminated: Widely dispersed across the entire body. Inimmune-compromised people, such as those with AIDS, coinfections (e.g.,cryptococcosis, histoplasmosis, Mycobacterium avium complex,etc.) may become disseminated and spread through the bloodstream toinfect lymph nodes, bone marrow, liver, spleen, spinal fluid, lungs,and the intestinal tract.
Division of Acquired Immunodeficiency Syndrome (DAIDS): Adivision of the National Institutes of Health's (NIH's) NationalInstitute of Allergy and Infectious Diseases (NIAID). DAIDS was formedin 1986 to address the national research needs created by the HIV/AIDSepidemic; to increase basic knowledge of the pathogenesis, naturalhistory, and transmission of HIV disease; and to support research topromote HIV detection, treatment, and prevention. See Also: National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH)
DNA: See: Deoxyribonucleic Acid
Dorsocervical Fat Pad: A type of lipodystrophy (a problem inthe way the body produces, uses, and distributes fat) in which fattytissue builds up on the upper back and neck. It most often occurs inHIV-infected people as a result of PI or NRTI drug treatment. This fatbuildup, also known as buffalo hump, may be associated with othermetabolic side effects, such as high insulin levels. See Also: Lipodystrophy, Body Habitus Changes
Dosage: The scheduled administration of individual drug doses,usually expressed as a quantity per unit of time. For example, aprescribed drug dosage may be 200 mg per day (but the individual dosecould
be 100 mg in the morning and 100 mg in the evening).
Dose: The measured amount of a therapeutic agent that is takenat one time, or the total amount taken during one time period. Forexample, a single dose of 100 mg may be taken at one time, or a totaldose of 1,000 mg may be taken during one 5-day treatment period. See Also: Dosage
Dose-Ranging Study: Clinical trial in which different doses ofa drug are tested to determine which is the safest and most effective.Before drugs are approved by the FDA, they must go through Phase I andII doseranging studies. See Also: Clinical Trial, Phase I Trial, Phase II Trial
Dose-Response Relationship: The relationship between the doseof a drug and its corresponding effect on the body. If a drug exhibitsa dose-response effect, it means that as the dose increases, so doesthe effect.
DOT: See: Directly Observed Therapy
Double-Blind Study: A clinical trial design in which neitherthe participants nor the study staff know which individuals arereceiving the experimental treatment and which are receiving a placebo(or another control therapy). Double-blind trials produce moreobjective results, because the expectations of the study staff and theparticipants do not affect the outcome. See Also: Controlled Trial
DRESS: See: Drug Rash with Eosinophilia and Systemic Symptoms
Drug Antagonism: An interaction between two or more drugs in which one drug blocks
or reverses the effect of another drug.
Drug Class: A group of drugs that share common properties, such as
mechanisms of action.
Drug Concentration: See: Concentration
Drug-Drug Interaction: A change in the way a drug works when itis taken along with another drug. The effect may be an increase or adecrease in the action of either drug, or it may be a side effect thatdoes not normally occur with either drug alone. See Also: Drug Interaction
Drug Formulation: See: Formulation
Drug Holiday: See: Structured Treatment Interruption (STI)
Drug Interaction: An effect that can occur when one drug istaken with another drug or when a drug is taken with particular foods.Possible effect
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