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Glossary of HIV / AIDS Terms


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Acute HIV Infection - The 4 to 7 week period following infection of rapid viral replication.

Acute - sudden and severe

Adverse Reaction - an unwanted effect detected in clinical trial in participants.

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

AIDS Dementia Complex (ADC) - A degenerative neurological condition attributed to HIV infection, characterized by a group of clinical presentations including loss of coordination, mood swings and loss of inhibitions and widespread cognitive dysfunction. This is the most common central nervous system complication of HIV infection.

AIDS DRUGS - An online database service of the National Library of Medicine, with information about drugs undergoing testing against AIDS, and related Opportunistic Infections. For information call the National Library of Medicine 1-800-638-8480.

AIDS Drug Assistance Program (ADAP) - State-based program funded through Ryan White CARE Act Title II funds that provide individuals with HIV and financial need necessary HIV medications and preventive treatments.

AIDS Service Organization (ASO) - A health association, support agency or other service related agencies actively involved in the prevention and treatment of HIV / AIDS.

AIDS Wasting Syndrome - Involves involuntary weight loss of 10% of baseline body weight plus either chronic diarrhea or chronic weakness and documented fever in the absence of a concurrent illness or condition other than HIV infection that would explain the findings.

Alpha Interferon - A protein- one of the three major classes of interferon's that the body produces in response to infections.

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.

Alternative Medicine - A broad category of treatment systems of culturally based healing traditions such as Chinese, Ayuredic, and Christian Science; is also referred to as "complementary medicine".

Analog - A compound with a structure similar to that of another compound but differing from it in respect to certain components or structural make-up.

Anamnestic Response - The heightened immunological reaction elicited by a second exposure to a particular antigen.

Anemia - A condition where there is a lower than normal level of red blood cells.

Anergy - The loss or weakening of the body's immunity to an irritating agent or antigen.

Antibiotic - A substance, especially one similar to those produced by certain fungi, that kills or inhibits the growth of microorganisms such as bacteria and fungi.

Antibodies - Molecules in the blood that destroy bacteria, viruses and other harmful toxin.

Asymptomatic - Without symptoms.

Antigen - Any substance that antagonizes or stimulates the immune system to produce antibodies.

Antiretroviral Agents - Substances used against retroviruses such as HIV.

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

Antiviral - A substance or process that destroys a virus or suppresses its replication.

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Bactericidal - Capable of killing bacteria.

Bacterium - A microscopic organism composed of a single cell can cause diseases.

Bioavailability - The extent to which an oral medication is absorbed in the digestive tract and reaches the bloodstream.

Biopsy - Surgical removal of a piece of tissue from a living subject for examination.

Branched DNA Assay (bDNA test) - Test for measuring the amount of HIV in blood plasma.

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Cachexia - General ill health and malnutrition, marked by weakness and emaciation, usually associated with a serious disease.

Candida - Yeast-like fungi commonly found in the normal flora of the mouth, skin, intestinal tract, and vagina that can be clinically infectious in immune-compromised persons.

Carcinogen - Any cancer causing substance.

Cardiomypathy - Cardiac (heart) muscle weakens arising from HIV medications and or an opportunistic infection associated with HIV disease progression.

CD4 (T4) or CD4+ Cells - A type of T-cell involved in protecting against viral, fungal, and protozoal infections. These cells normally orchestrate the immune response, signaling other cells in the immune system to perform special duties. These are also known as T-helper cells. Although CD4 counts fall, the total number of T-cell level remains fairly constant through the course of HIV disease, due to the concomitant increase in the CD8+ cells. The ratio of CD4+ to CD8+ cells is therefore an important measure of disease progression.

CD4 Cell Count - The number of CD4 cells in a microliter of blood. The normal range for CD4 cell counts is 500 to 1500 per cubic milliliter of blood.

Chemokines - Also called beta chemokines. Studies of the relationship between HIV and these immune system chemicals have shown the complex exchange that take place when HIV and white blood cells meet.

Chlamydia - One of the most common sexually transmitted bacterium that infects the reproductive system.

Clinical - Pertaining to or founded an observation and treatment of patients, as distinguished from theoretical or basic science.

Codon - A sequence of three nucleotides of messenger RNA that specifies addition of a particular amino acid to, or termination of, a polypeptide chain during protein synthesis.

Combination Therapy - Two or more drugs of treatments used to achieve optimum results against HIV infection. Most combinations use two nucleoside analog plus either a protease inhibitor or a non-nucleoside reverse transcriptor inhibitor.

Compassionate Use - A method of providing experimental therapeutics prior to final FDA approval for humans. This is used for very sick individuals who have no other treatment options.

Complementary Therapy - A whole range of services designed to complement traditional medical practice as part of a practitioner's primary care plan for an individual.

Contagious - a virus that can be transmitted through casual contact, as defined by normal day-to-day activities with people at home, work and or school. HIV is known as an infectious disease because intimate (sex, sharing needles) contact is required for transmission to occur.

Cross Resistance - The phenomenon in which a microbe that has acquired resistance to one drug through direct exposure, also turns out to have resistance to one or more drugs to which it has not been exposed.

Cryptococcal Meningitis - A life-threatening infection of the membranes that line the brain and the spinal cord caused by a fungus. Is rare in persons who do not have a suppressed immune system.

Cryptosporidiosis - An infection caused by a protozoan parasite found in the intestines of animals. Once transmitted to man, it lodges in the intestines and causes severe diarrhea.

Cytomegalovirus (CMV) - A herpes virus that is common cause of opportunistic diseases in persons with HIV disease. CMV can infect most organs of the body. Persons with AIDS are most susceptible to CMV retinitis and colitis.

Cytomegalovirus Retinitis - Most adults in the US have been infected, however the virus does not cause disease in people who do not have a compromised immune system. WIthout treatment persons with CMV Retinitis can loose their sight, this is the most common cause of blindness for persons living with HIV.

Cytopenia - Deficiency in the cellular elements of the blood.

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Dendritic Cell - Patrolling immune system cells that may begin with the HIV disease process by carrying the virus from the site of the infection to the lymph nodes, where other immune system cells become infected.

Deoxyribonucleic Acid (DNA) - The molecular chain found in genes within the nucleus of each cell, which carries the genetic information that enables cells to reproduce.

Desensitization - Gradually increasing the dose of a medicine in order to overcome severe reactions. Desensitization procedures have become popular when administering Bactrim to persons with a history of adverse reaction to the drug.

Diplopia - Double Vision.

Disseminated - Spread throughout the body.

Drug Resistance - The ability of some disease-causing microorganisms, such as bacteria to adapt themselves to grow and to multiply even in the presence of drugs that kill them.

Dyspepsia - Digestive upset, which may include flatulence, heartburn, nausea, and vomiting.

Dysplasia - Any abnormal development of tissue of organs. In pathology, alteration in size, shape and organization of adult cells.

Dyspnea - Difficult or labored breathing.

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Edema - Swelling caused by an abnormal accumulation of fluid in the body tissue.

ELISA (Enzyme-Linked Immunosorbent Assay) - A blood test which indicates the presence of antibodies to HIV. It does not detect HIV disease, but only indicates if antibodies are present in the blood or oral fluids.

End-Stage Disease - Final period or phase in the coarse of a disease leading to a person's death.

Enteric - Pertaining to the intestines.

Enteritis - Inflammation of the intestines.

ENV - A gene of HIV that codes for the protein gp160, the precursor of the envelope proteins gp120 and gp41.

Epidemic - A disease that spreads rapidly through a demographic segment of the human population, such as everyone in a given geographic area.

Expanded Access - Refers to any of the FDA procedures, such as compassionate use, parallel track and treatment IND, that distribute experimental drugs to patients who are failing on currently available treatments for their condition and also are unable to participate in ongoing clinical trials.

Expression System - In HIV vaccine production, cells into which an HIV gene has been inserted to produce desired HIV proteins.

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Floaters - Drifting dark spots within the field of vision. Floaters can be caused by infection with Cytomegalovirus (CMV) retinitis but also can appear in persons as a normal part of the aging process.

Folic Acid - A crystalline vitamin of the B complex that is used especially in the treatment of nutritional anemias. It can be found in greens, fresh fruit, liver and yeast.

Functional Antibody - An antibody that binds to an antigen and has an effect.

Fungus - One group of primitive non-vascular organisms including mushrooms, yeasts, rusts, and molds.

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Gene - A unit of DNA that carries information for the biosynthesis of a specific product in the cell.

Gene Therapy - Any of number of experimental treatments in which genes are altered.

Gonorrhea - A common sexually transmitted bacterial infection. Symptoms include difficulty urinating, a greenish-yellow discharge and itching, and burning or tenderness around the vagina or urethra.

GP41 - Glycoprotein 41 is a protein in the outer envelope of HIV. Plays a key role in HIV's infection of CD4+ T-cells by facilitating the fusion of the viral and the cell membranes.

GP120 - Glycoprotein 120 is a protein that protrudes from the surface of HIV that binds to CD4+ T cells in a two step process that allows HIV to breach the membrane of T cells, gp120_CD4 complex refolds to reveal a second structure that binds to CCCKR5, one of several chemokines co-receptors used by the virus to gain entry into the T cell.

Gp160 - A precursor of HIV envelope protein gp41 and gp120.

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HAART (Highly Active Antiretroviral Therapy) - Refers to milti-drug combinations used to fight HIV, uses combinations of three or more Antiretroviral.

HCV (Herpes C Virus) - The virus that causes Hepatitis C.

Half-Life - The time required for half of the amount of a drug to be eliminated from the body.

Helper / Suppressor Ratio - T-cells are lymphocytes that are formed in the thymus and are part of the immune system. They have been found to be abnormal in someone with HIV.

Helper T Cells - Lymphocytes bearing the CD4 marker that are responsible for many immune system functions, including turning antibody production on or off.

Hepatitis - An inflammation of the liver. May be caused by bacterial or viral infection, parasite infestation, alcohol, drugs, toxins, or transfusion of incompatible blood.

Human T Cell Lymphotropic Virus Type II (HTLV II) - A virus closely related to HTLV-I shares 60% genomic homology with HTLV-I. Found predominately in injection drug users and Native Americans, as well as Caribbean and South American Indian groups HTLV-II has not been linked to any disease but has been associated with several neurological diseases.

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Idiopathic - Without a known cause.

Immune Complex - Clusters formed when antigens and antibodies bind together.

Immune Deficiency - A breakdown or inability of certain parts of the immune system to function, thus making a person susceptible to certain diseases.

Immune Response - The activity of the immune system against a foreign body.

Immune System - The body's natural defenses against disruption causes by invading foreign bodies. There are two parts to the immune system the innate and the acquired. The innate part of the response is mobilized very quickly and does not depend on recognizing certain proteins or antigens foreign to an individual's normal tissue. The acquired immune response arises when Dendritic cells and macrophages present pieces of antigen to lymphocytes, which are genetically programmed to recognize very specific amino acid sequences. The end result is the creation of cloned antibody producing B cells and cytotoxic T lymphocytes primed to respond to a unique pathogen.

Immunity - A natural resistance to a specific disease.

Immunocompetent - Capable of developing an immune response, or a normal healthy immune system.

Immunodeficiency - Breakdown in immunocompetence.

Immunogen - Also called an antigen, is a substance capable of provoking an immune response.

Immunostimulant - Any substance that triggers or enhances the body's defense mechanism.

Immunosuppression - A state of the body in which the immune system is damaged and does not perform as it should.

Incubation Period - The time interval between the initial infection with a pathogen and the appearance of the first symptom or sign of disease.

Infection - The state in which the body is invaded by an infectious agent for which the body's immune system is working to combat or is unable thereby producing an injurious effect (active infection).

Infectious - An infection capable of being transmitted by direct or intimate contact.

Informed Consent - The permission granted by a participant in a research study after they have received comprehensive information about the study or where certain tests are to be performed.

Integrase - This enzyme inserts HIV's gene into a cell's normal DNA operating after reverse transcriptase has created a DNA version or RNA form of HIV genes present in the virus particles. Plays a vital role in the HIV-infection process.

Intermediate Stage - A period that can last for many years, during which HIV replicates in the lymph nodes patients often remain asymptomatic during this stage.

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Jaundice - Yellow pigmentation of the skin and whites of the eyes caused by the elevated blood levels of bilirubin.

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Kaposi's Sarcoma (KS) - An AIDS defining illness consisting of cancerous lesions caused by the overgrowth of blood vessels. KS typically appears as pink or purple spots on the surface of the skin, can also occur internally. There has been speculation that KS is not a spontaneous cancer but is sparked by a herpes virus.

Killer T Cells - Because viruses lurk inside the host cells where antibodies cannot reach them, the only way they can be eliminated is by killing the infected host cell, this is where the Killer T cell comes in. These cells only act when they encounter another cell that carries a "marker" that links it to a foreign protein.

KSHV - Kaposi's Sacoma Herpes Virus.

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Latency - An inactive or resting period during a disease process. Clinical latency is an asymptomatic period in the early years of HIV infection (for some people). Recent research shows that the firus during this asymptomatic period is actually replicating at a rapid pace in the lymph nodes.

Lentivirus - Virus characterized by a long period between infection and the onset of symptoms.

Lesion - A general term to describe an area of altered tissue.

Leukocytes - Any of the various white blood cells that together make up the immune system.

Lipid - Any of the group of fats.

Log - Changes in viral load are often reported as a logarithmic change. This is a mathematical term that denotes a change in what is being measured by a factor of ten.

Long-Term Non-Progressors - Individuals who have been living with HIV for at least 7 to 12 years and have stable CD4+ T cell counts of 600 or more, no related HIV diseases and no previous Antiretroviral therapy.

Lymph - A transparent, slightly yellow fluid that carries lymphocytes. Comes from the tissue fluids collected from all parts of the body and is returned to the blood.

Lymph Nodes - Small organs of the immune system, lymph fluid is filtered through the lymph nodes in which all types of lymphocytes take up temporary residence.

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Macrophage - A large cell of the immune system that helps clear the infections from the body.

Malabsorption Syndrome - Decreased intestinal absorption resulting in loss of appetite, muscle pain, and weight loss.

Malaise - A generalized, nonspecific feeling of discomfort.

Malignant - Refers to cells or tumors growing in an uncontrolled fashion. All cancers are considered to be malignant.

Memory T Cell - A subset of T lymphocytes that have been exposed to specific antigens and can proliferate on subsequent immune system encounters with the same antigen.

Meningitis - An inflammation of the meninges (membranes surrounding the brain or spinal cord) which may be caused by bacteria, fungus, or firus.

Messenger RNA - An RNA that carries the genetic code for a particular protein from the DNA in the cell's nucleus to a ribosome in the cytoplasm and acts as a template for the formation of that protein.

Metastasis - Transfer of a disease-producing agent from one part of the body to another.

Microencapsulated - Surrounded by a thin layer of protection, can refer to either a drug or vaccine. Protects from rapid breakdown.

Microsporidiosis - An intestinal infection that causes diarrhea and wasting in persons with HIV.

Molluscum Contagiosum - A disease of the skin and mucous membranes caused by a poxvirus.

Mononeuritis Multiplex - A rare type of neuropathy associated with HIV infection, may be related to CMV.

Monotherapy - Treatment consisting of a single drug.

Multiple Drug Resistant Tuberculosis (MDR-TB) - A strain of TB that does not respond to two or more standard anti TB drugs.

Mutation - A sudden change in a gene that results in a new characteristic.

Myalgia - Diffuse muscle pain, usually accompanied by malaise (a general feeling of discomfort).

Mycobacterium Avium Complex (MAC) - A common opportunistic infection caused from certain bacteria found in dust and soil.

Mycosis - Any disease caused by a fungus.

Myopathy - Progressive muscle weakness that may arise from a toxic reaction to AZT or as a symptom of HIV.

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Naïve T Cell - A T cell arising from the immune system's production of fresh cells in the bone marrow. Naïve T cells respond to newly-encountered pathogens containing antigens the immune system has not processed before. The naïve T cell's activation and proliferation create an acquired immune response to a newly-encountered pathogenic agent. After the disease is eradicated, a portion of the T cell population engendered by the activated naïve T cells constitutes a reservoir of memory cells, which proliferates very quickly to any recurrence of the disease.

Natural Killer Cells - A type of lymphocyte that attacks and kills tumor cells and protects against a wide variety of infectious microbes. They do not need additional stimulation to attack. Persons with HIV have a decrease in these cells.

NEF - One of the three regulatory genes of HIV, contains information necessary for the production of proteins that control the vuris' ability to infect a cell.

Neuropathy - The name given to a group of disorders involving the nerves. Symptoms range from a tingling sensation or numbness in the toes and fingers to paralysis, may be a side-effect of medications. It is estimated that 35% of persons living with HIV have some form of neuropathy neutralization-The process by which an antibody binds to a specific antigen thereby neutralizing the organism.

Neutralizing Antibody - An antibody that keeps a virus from infecting a cell, usually blocking receptors on the cell of the virus.

Night Sweats - Extreme sweating during sleep. Non-Hodgkin's Lymphoma (NHL) - A lymphoma made of B cells and characterized by diffuse tumors that may appear in the stomach, liver, brain, and bone marrow, of persons with HIV.

Non-Nucleoside Reverse Transcriptase Inhibitors - A new third calss of HIV drugs, that act to directly combine with and block the action of HIV's enzyme.

Nucleoside Analog - An HIV drug, acting to replace natural nucleosides and block the completion of the viral DNA chain during infection of a new cell by HIV.

Nucleotide Analogs - Chemically related to nucleoside analogs, nucleotide analogs are beginning to draw attention as agents that could fight AIDS related infections as well as HIV.

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Opportunistic Infection - Illnesses caused by various organisms, some of which usually do not cause disease in persons with normal immune systems.

Oral Hairy Leukoplakia (OHL) - A whitish lesion that appears on the side of the tongue and inside cheeks, occurs in people with declining immunity and may be caused by Epstein-Barr virus.

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Palliative - A treatment that provides symptomatic relief but not a cure.

Palliative Care - An approach to live-threatening diseases and chronic illnesses, especially at the end of life.

Passive Immunotherapy - Process in which individuals with advanced disease are infused with plasma rich in HIV antibodies or an immunoglobin concentrate.

Pathogen - Any disease-producing microorganism.

Pelvic Inflammatory Disease (PID) - Gynecological condition caused by an infection that spreads from the vagina to the upper parts of a woman's reproductive tract in the pelvic cavity.

Perinatal Transmission - Transmission of a pathogen (HIV) from mother to baby before, during or after the birth process.

Pneumocystis Carinii Pneumonia (PCP) - An infection in the lungs very common in persons living with HIV.

Progressive Multifocal Leukoencephalopathy (PML) - A rapidly debilitating opportunistic infection that affects the brain and the spinal cord.

Prophylaxis - Treatment to the onset of a particular disease, or the reoccurrence of symptoms in an existing infection that is now under control.

Protease - An enzyme that breaks down proteins into their component peptides.

Protease Inhibitors - HIV protease is an enzyme that is essential for replication to occur, these drugs inhibit them and thus interfer with the replication of the virus.

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Q - R

RNA - Genetic material within cells necessary for transmission of genetic information for replication and function.

Remission - The lessening of the severity or duration of out breaks of a particular disease.

Resistance - Reduction in a pathogen's sensitivity to a particular drug, thereby making the drug less effective.

Retrovirus - A type of virus that, when not infecting a cell, stores its genetic information on a single stranded RNA.

REV - One of the regulatory genes of HIV.

Reverse Transcriptase - These fight HIV by interfering with the stage of the viral life cycle that converts the single stranged RNA into a double stranded RNA.

Ryan White Care Act - Through the Ryan White Comprehensive Emergency AIDS Resources (CARE) Act health care, support services, medical care, prescription services, education and research to name a few are supported by the federal government for persons living with HIV.

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Seroconversion - The development of antibodies to a particular antigen.

Simian Immunodeficiency Virus (SIV) - An HIV-like virus that infects monkeys, chimpanzees, and other nonhuman primates.

Standards of Care - Treatment regimen or medical management based on state-of-the-art patient care.

Suppressor Phenomenon - Process where CD8+ cells not only kill HIV-infected cells directly by a process called cytolysis, but also secrete soluble factors that suppress HIV replication in both blood and lymph nodes.

Susceptible - Vulnerable or predisposed to a disease.

Symptoms - Any perceptible, subjective change in the body or its functions that indicates disease, or the use of medication.

Syndrome - A group of symptoms as reported by the patient and signs detected in an examination that together are characteristic of a specific condition.

Syphilis - A disease primarily sexually transmitted resulting from infection with certain bacteria.

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TAT - One of the regulatory genes of HIV.

T-Cells - Are white blood cells, derived from the thymus gland, that participate in a variety of cell medicated immune reactions.

TH1 Response - An acquired immune response whose most prominent feature is high cytotoxic T lymphocyte activity relative to the amount of antibody production.

TH2 Response - An acquired immune response whose most prominent feature is high antibody production relative to the amount of cytotoxic T lymphocyte activity.

Thrombocytopenia - A decreased number of blood platelets.

Thrush - Sore patches in the mouth caused by a fungus, yeast.

Toxoplasmosis - An infection that is caused by the parasite that is often carried by cats, birds, and other animals. Once infected the virus stays there but depending on ones immune system determines the bodies' reaction.

Tuberculosis (TB) - A bacterial infection spread by airborne droplets expelled from the lungs when a person with active TB coughs, sneezes, or speaks.

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U - V

Viral Burden - The amount of HIV in the circulating blood. A new, sensitive, rapid test called the viral load assay for HIV-1 infection can be used to measure the HIV viral burden.

Viral Load Test - As related to HIV: Test that measures the quantity of HIV in the blood. Results are expressed as the number of copies per milliliter of blood plasma.

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W, X, Y, Z

Western Blot - A test for specific antibodies to confirm repeatedly reactive results on the ELISA or EIA test.

Window Period - Time from infection with HIV until detectable seroconversion.

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