Speaking HIV/AIDS: A Glossary of Terms to Describe Immune Deficiency, Symptoms, Tests, Treatment, and More
A brief look at some of the terms used in the fast-changing world of HIV/AIDS medicine.
Since the term “AIDS” itself was first used to identify a mysterious and deadly illness in 1982, more than 75 million people have been affected by the human immunodeficiency virus and the life-threatening syndrome, AIDS (acquired immune deficiency syndrome), that can develop from it. The condition and the treatments that accompany it have changed the face of medicine — and its vocabulary.
New drugs for HIV/AIDS are being developed constantly, while breakthrough research is offering new hope. And lately, a surprising word has begun to creep into the conversation: cure. The following glossary represents a snapshot of some of the many — and ever-changing — terms, phrases, and concepts used in HIV medicine today.
Abacavir (1592 or Ziagen) This nucleoside reverse transcriptase inhibitor (NRTI) is an antiretroviral drug.
Acute antiretroviral Drugs capable of stopping or eliminating retroviruses are called “anti-retroviral” drugs. They work by preventing HIV cells from reproducing.
AIDS case definition To be diagnosed with AIDS, as opposed to HIV positive, an individual must present with a medical condition particular to the more advanced form of the infection — such as Kaposi’s sarcoma — or with a CD4 count of less than 200 cells/mm³ (regardless of whether the person has an AIDS-defining condition).
Amprenavir Also called Agenerase, Amprenavir is a protease inhibiting drug (PI) prescribed for the treatment of HIV-1 infection.
Antibody differentiation test In a diagnosed HIV infection, this antibody test allows doctors to differentiate between HIV-1 and HIV-2 antibodies. HIV 2 is uncommon in North America.
Antiretroviral (ARV) ARVs denote a particular class of HIV drugs that have helped transform the illness into a manageable, ongoing condition. They function by preventing the virus from creating copies of itself.
Antiretroviral therapy (ART) ART is the treatment regimen based on ARV drugs, usually a combination therapy (cART) or a highly active antiretroviral therapy (HAART) that draws from a variety of pharmaceutical products.
Apoptosis Also called “cellular suicide,” apoptosis is the body’s way of eliminating old or damaged cells through programmed death. In HIV, apoptosis may destroy the healthy immune system along with healthy tissue by rendering the body unable to differentiate between healthy and diseased cells.
Attachment inhibitor Attachment-inhibiting drugs prevent HIV from binding to and invading normal cells. Still under investigation, these formulations have not yet been approved for patient use by the U.S. Food and Drug Administration (FDA), but many researchers are hopeful about their potential as HIV drugs.
Azidothymidine (AZT) Short for azidothymidine and also called zidovudine, this nucleoside reverse transcriptase inhibitor (NRTI) became the first drug in this class to be approved for HIV treatment, in 1987.
B lymphocyte The immune system’s B cells produce antibodies capable of helping to fight infection.
Backbone The term is used to describe the initial HIV drug regimen, a “backbone” of medications that included two nucleoside reverse transcriptase inhibitors (NRTIs) and a third medication: either a non-nucleoside reverse transcriptase inhibitor antiretroviral (NNRTI), a protease inhibitor (PI), or an integrase strand transfer inhibitor (INSTI).
Body habitus change Visible alterations in the overall body shape or appearance, these are among the most common known side effects of some HIV drugs. Affected individuals can deposit visceral fat around their midsection, lose fat from other areas, or develop a "hump" on the upper back.
Branched DNA assay Known as the bDNA test, this screening test measures the amount of HIV and other viruses in the blood. The test helps doctors determine whether treatments are working well.
Broadly neutralizing antibody (bNAb) These antibodies can identity and block HIV cells from damaging healthy cells. Research into bNAbs has the potential to one day spawn an anti-HIV vaccine, according to some researchers.
CCR5 and CXCR4 Found on the surface of some of the body’s immune cells, these molecules act as co-receptors allowing HIV to attack healthy cells. CCR5 is believed to be the primary co-receptor in earlier stages of the disease, with CKR5 and CXCR4 taking over later in the disease.
CD4 cell White blood cells, also sometimes referred to as T cells, T lymphocytes, or T helper cells. The number of CD4 cells in a blood sample is sometimes used as a marker of the strength of the immune system.
CD4 count This laboratory test measures the number of CD4 cells in the blood, to help physicians gauge the strength of immune response and the progression of the HIV infection. It’s often used to determine whether the body is responding properly to antiretroviral therapy (ART).
Comorbidity and coinfection Comorbidity describes the simultaneous presentation of two health problems, for example, HIV and diabetes. Coinfection describes a similar situation in which both comorbidities are infections, such as HIV and hepatitis C.
Combivir A combined pill containing AZT and 3TC.
Compassionate use When a still-unapproved medication shows unusual promise, some extremely sick patients can appeal to receive the drugs from the manufacturer before formal FDA approval. The policy is viewed as a compassionate means to provide hope to people with advanced disease.
Crixivan (indinavir) An antiviral medication, Crixivan is a protease inhibitor (PI) used in HIV.
Cross resistance and cross sensitivity When a patient develops resistance or sensitivity to a particular drug, there can be “cross effects” — the patient becomes cross resistant or, alternatively, cross sensitive to other medications in the same class.
Cytokine Proteins produced primarily by cells of the immune system to dispatch chemical messages that help regulate the body’s response to infection.
d4T (stavudine) Known by the brand name Zerot. This nucleoside analog reverse transcriptase drug is an antiretroviral.
ddC (zalcitabine) An antiretroviral drug, ddC is often used alongside AZT (formerly called dideoxycytidine) under the brand name Hivid.
ddI (didanosine) Also called dideoxyinosine, ddl is an anucleoside analog reverse transcriptase drug with the brand name Videx. It carries a risk for pancreatitis.
Dorsocervical fat pad The so-called “buffalo hump” of fat cells that can appear between the shoulders, it is one of the “body habitus changes” that can accompany the use of some antiretroviral drugs.
Drug class Medications that share common properties and treatment mechanisms are said to belong to a class. Approved antiretroviral (ARV) HIV drugs fall into seven different classes, according to how they block the immunodeficiency virus. The classes are nucleoside reverse transcriptase inhibitors (NRTIs), nonnucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs), fusion inhibitors, CCR5 antagonists, post-attachment inhibitors, and integrase strand transfer inhibitors (INSTIs).
Dyslipidemia This buildup of lipids or fats in the blood can result from some HIV treatments, which hike levels of cholesterol or triglycerides.
ELISA The enzyme-linked immunosorbent assay (ELISA) is a laboratory test that helps confirm the presence of HIV and other infection in blood or saliva.
Elite controller The rare individuals who remain free of viral HIV without any antiretroviral therapy (ART) are dubbed “elite controllers.” Their physiology may help scientists uncover keys to future treatments.
Entry inhibitor These antiretroviral (ARV) drugs prevent HIV from entering CD4 cells. The class includes fusion inhibitors, CCR5 antagonists, and post-attachment inhibitors.
Epivir (lamivudine) An antiretroviral medication usually used in combination with AZT.
Fixed-dose combination (FDC) FDC is a treatment protocol that blends two or more drugs in a single capsule or tablet. It represents the daily treatment method for many people living with HIV today.
Fusion inhibitor Fusion inhibitors such as Enfuvirtide block HIV from binding to T cells.
Genotype The genotype drug test examines an individual virus's genetic makeup to help determine which medications are most likely to reduce the viral load of HIV in the bloodstream. Blood samples are subjected to the genotypic antiretroviral resistance test (GART) to determine if drug-resistant mutations in HIV genes could block common treatments.
HAART Highly active antiretroviral therapy.
HIV continuum of care The care continuum describes the steps or stages of medical treatment for people living with HIV. It proceeds from the initial diagnosis through the designation of a treatment team, the treatment regimen itself, the monitoring of the patient’s compliance with physician instructions, and monitoring methods used to ensure ongoing treatment success
HIV life cycle As an HIV infection progresses, the invading cells proceed along some predictable phases. These are (1) binding; (2) fusion; (3) reverse transcription; (4) integration; (5) replication; (6) assembly; and (7) budding. The disease itself is characterized by the stage of infection, from acute HIV infection, to chronic HIV infection, to AIDS.
HIV-1 and HIV-2 HIV-1 is the form of the virus most commonly seen in North America and around the world. It occurs when HIV-infected body fluids such as blood, semen, vaginal fluids, or infected breast milk are directly transmitted to another person. HIV-2 is primarily found in West Africa and usually takes longer to transition into full-blown AIDS.
Hypertriglyceridemia A possible side effect of antiretroviral drugs, hypertriglyceridemia promotes excessive accumulation of triglycerides, raising the risk for cardiovascular disease.
Integrase This enzyme helps HIV gain access to the DNA of the body’s CD4 cells, a process blocked by the integrase strand transfer inhibitor (INSTIs) class of antiretroviral drugs.
Immune modulator Immunomodulators are medications that can enhance, improve, or restore normal immune function after HIV has damaged cells. They have yet to receive FDA approval for patient use.
Integrase A little-understood enzyme, this substance apparently plays an important part in allowing HIV to insert its genetic material into normal cell DNA.
Invirase (saquinavir, fortovase) This drug belongs to the protease inhibitor class of anti-HIV drugs.
Kaposi's sarcoma This blood vessel cancer was among the first illnesses to herald the progression of the HIV virus to full-blown AIDS. Kaposi’s can cause obvious purple bruises and marks on the skin, but it can affect any organ. It is caused by a virus called the human herpesvirus 8 (HHV-8), also known as the Kaposi's sarcoma-associated herpesvirus (KSHV),
Latency-reversing agent This promising, but still unapproved, class of drugs is believed to effectively target HIV during early infection, when the virus remains hidden and difficult to treat.
Lipodystrophy The clinical term denotes the bodily changes — from the so-called "buffalo hump” to the "protease paunch” and the "Crixivan potbelly" — that can occur as a side effect of protease-inhibiting drugs. Lipodystrophy redistributes body fat, making veins seem to protrude while wasting the face and limbs. The condition can deposit fat around the abdomen, increasing the person's odds of developing diabetes.
Lymphocyte Lymphocytes are white blood cells — called T cells and B cells — essential to the functions of a healthy immune system.
Macrophage These white blood cells, when healthy, engulf and consume infected cells, disease agents, and dead material.
Metabolic syndrome Metabolic syndrome is a dangerous form of overweight or obesity that has reached epidemic proportions in the United States and other Western nations. Diagnosis involves at least three of the following symptoms: high blood pressure, abdominal obesity, high triglycerides, low levels of high-density lipoprotein (HDL) cholesterol, or high fasting blood sugar levels. Some retroviral drugs appear to worsen the syndrome.
Monocyte A type of white blood cell.
Natural killer cell (NK cell) In healthy individuals, these lymphocytes safeguard the body by attacking and killing a wide variety of infectious microbes. The cell earned the “natural” moniker for its ability to spontaneously recognize specific invaders and kill them. People living with HIV have diminished NK capacity.
Neutropenia The term used to denote a shortage of white blood cells, which increases the risk for bacterial and fungal infections among those with immunocompromising disease.
NNRTI-sparing regimen combination This antiretroviral therapy (ART) allows patients to avoid some of the side effects of HIV treatment by omitting drugs from the non-nucleoside reverse transcriptase inhibitor (NNRTI) class from their treatment.
Norvir (ritonavir) This protease inhibitor combined with nucleoside analogs is commonly used in HIV-positive adults and children over age 2.
Opportunistic infection Rarely seen in healthy individuals, these ailments serve as warning signs that the body’s immune function has been compromised, either by an HIV infection or chemotherapy. Common opportunistic infections include pneumonia, salmonella, and tuberculosis, and can be bacterial, viral, fungal, or parasitic organisms.
Parenteral transmission (of HIV) The injection of HIV into the body, most commonly through HIV-contaminated needles, is becoming the leading vehicle of disease transmission in the wake of the opioid crisis.
Persistent generalized lymphadenopathy This condition, in which enlarged lymph nodes appear in at least two areas of the body and remain for at least three months, is often an early sign of HIV as well as opportunistic infections.
Phagocyte The phagocyte is a cell capable of ingesting and obliterating foreign matter, including bacteria.
Phenotype or phenotypic essay Phenotype screening allows doctors to pinpoint the medication best able to destroy HIV, as indicated by an individual’s DNA. Blood cells are tested with several antiretrovirals to see which generates the greatest response and results are used to create a customized treatment plan. Testing occurs during the initial stages of HIV and when changing antiretroviral therapies (ARTs).
PI-sparing regimen combination An antiretroviral therapy, PI-sparing excludes protease inhibitors from among the roster of antiretrovirals used in some HIV cases. The change is made to enable some people living with HIV to avoid side effects.
Polymerase chain reaction (in HIV) This laboratory test can detect HIV by amplifying and looking for genetic information about an individual HIV profile.
Post-attachment inhibitor This class of drugs blocks HIV from invading CD4 cells.
PrEP prophylaxis (PrEP) For those at high risk of acquiring HIV, PrEP (stands for pre-exposure prophylaxis) employs a specific combination of HIV medicines which, when used with condoms and other prevention tools, can diminish the chance that some particularly high-risk patients will develop HIV.
Protease inhibitor (PI) PI drugs, including the FDA-approved saquinavir, indinavir, amprenavir, lopinavir, ritonavir, nelfinavir, and atazanavir, release an enzyme that prevents formation of new HIV viruses. The medications are administered alongside nucleoside and non-nucleoside analogs.
Quasispecies These mutant viruses are spawned during the HIV replication process, confusing the body and complicating the mechanisms that can help locate and disable invaders. The sequence that generates quasispecies can frequently be arrested by antiretroviral medications taken during the early stages of HIV.
Rapid test An HIV antibody screening, this test detects HIV in blood or orally in less than 30 minutes. A second, confirmatory test is usually required for a definitive HIV diagnosis.
Resistance When HIV fails to respond to the prescribed medications, it is said to be “resistant.” The problem often occurs when a patient has not taken his or her medication properly; either skipping doses, taking the wrong dosage, or discontinuing the drug entirely. Once resistance develops it is usually permanent.
Retrovirus Retroviruses copy genetic material using RNA as a template for making DNA.
Reverse transcriptase This enzyme is found in HIV and other retroviruses, where it sets the stage for the conversion of cellular RNA into viral DNA. Nonnucleoside reverse transcriptase inhibitors (NNRTIs) prevent HIV from replicating by blocking RT.
Ribonucleic acid (RNA) RNA is the genetic material of HIV.
Salvage therapy “Salvage” describes the treatment approach used when patients fail to respond to regular protocols or are unable to tolerate the drugs.
Shock and kill strategy This experimental treatment strategy targets the earliest-stage HIV-infected cells, which can remain hidden from the body’s immune system or inactive for months or years. The approach “shocks” the body into revealing the cells with latency-reversing drugs and then destroys now-visible organisms with immune-boosting pharmaceuticals.
Sustiva (efavirenz) An antiretroviral used in HIV combination therapy. Its brand name is Sustiva.
T cells T-helper lymphocytes, of which one essential component are CD4-lymphocytes (same as CD4 cells), which are white blood cells essential to the regulation of the body’s immune system and the control of B cell and macrophage functions. T types orchestrate antibody production, activate other T cells, and launch other immune responses.
Trizivir This brand-name HIV antiretroviral combines Zidovudine (AZT/ZDV), Lamivudine (3TC) and Abacavir (ABC/1592) in a single tablet.
Undetectable viral load When the amount of HIV in the blood is too low to return any readable laboratory results, the person is said to have an “undetectable viral load.” If they remain at the undetectable level for at least six months, an individual’s HIV is said to be “durably undetectable.” Despite that, minuscule amounts of the virus remain in the body and can quickly reignite the infection if medications are misused or discontinued.
Viracept (nelfinavir) A protease inhibitor, nelfinavir is an antiretroviral medication is used in HIV treatment, often under the brand name.
Viral load The amount of HIV virus in the blood is determined by a blood test. Screening is common before and during treatment.
Viramune (nevirapine) A non-nucleoside reverse transcriptase inhibitor, nevirapine is used in combination with antiretroviral agents to treat HIV-1 infection in adults and children 2 months or older. The drug, less expensive than AZT, is believed to be just as effective in preventing HIV transmission.
Western blot A confirmatory blood test for HIV infection, this screening is often ordered after a rapid test reveals the presence of the infection.
White blood cells (WBC) Critical disease-fighting components of the body’s immune system composed of neutrophils, lymphocytes, monocytes, eosinophils, and basophils.
Wild-type virus The original form of HIV, unchanged by having developed any resistance to antiretroviral drugs, is referred to as the “wild type.”
Zalcitabine A nucleoside reverse transcriptase inhibitor, this medication is often administered in conjunction with antiretroviral agents to treat HIV patients 13 and older. It’s also referred to as ddC, under the brand name HIVID.
Zerit (stavudine) A nucleoside reverse transcriptase inhibitor, stavudine is sold under the brand name Zerit.
Zidovudine This nucleoside reverse transcriptase inhibitor is used alongside other antiretroviral agents for adults and children older than 3, as well as for pregnant women between 14 and 34 weeks’ gestation and during labor. Zidovudine can be given to newborns.