D
Data and Safety Monitoring Board (DSMB) 
(En español)
A committee of clinical research experts, such as physicians and statisticians, and patient advocates who monitor the progress of a clinical trial and review safety and effectiveness data while the trial is ongoing. This committee is independent of the people, organizations, and institutions conducting the clinical trial. Data and Safety Monitoring Boards (DSMBs) can recommend that a trial be stopped early because of concerns about participant safety or because the main research question has been answered.
See Related Term(s): Clinical Trial
For certain; without a doubt. An initial positive HIV antibody test must be confirmed by a positive Western blot test for a person to have a definitive diagnosis of HIV infection.
See Related Term(s): Presumptive
A type of antigen-presenting cell found in many tissues throughout the body. Dendritic cells capture antigens with their threadlike tentacles and present the antigens to T lymphocytes (T cells), stimulating an immune response.
See Related Term(s): Antigen-Presenting Cell
An experimental vaccine that uses dendritic cells to boost the immune system. Dendritic cell vaccines are currently being studied as a possible way to treat people with HIV.
See Related Term(s): Dendritic Cell
Deoxyribonucleic Acid (DNA) (En español)
One of two types of genetic material found in all living cells and many viruses. (The other type of genetic material is RNA.) Deoxyribonucleic acid (DNA) carries the genetic instructions for the development and function of an organism. DNA allows for the transmission of genetic information from one generation to the next.
See Related Term(s): Ribonucleic Acid
Department of Health and Human Services (HHS) (En español)
The primary federal agency for protecting the health of all Americans and providing essential human services. The Department of Health and Human Services (HHS) works closely with state and local governments, and many HHS-funded services are provided at the local level by state or county agencies, or through private sector grantees. The agency’s 11 operating divisions, including the Centers for Disease Control and Prevention (CDC), the Food and Drug Administration (FDA), and the National Institutes of Health (NIH), collectively administer more than 300 HHS programs.
See Related Term(s): Centers for Disease Control and Prevention, Food and Drug Administration, National Institutes of Health
A mood disorder characterized by sadness, inactivity, and inability to take pleasure or interest in usual activities. The changes in mood can interfere with daily life and normal functioning. Use of some antiretroviral (ARV) drugs may cause depression.
Preventing or reducing a hypersensitivity reaction to a drug by gradually increasing the dose of the drug.
See Related Term(s): Hypersensitivity, Rechallenge
Also known as: Diabetes Mellitus
A group of diseases characterized by high levels of blood sugar (glucose). Type I diabetes occurs when the body fails to produce insulin, which is a hormone that regulates blood sugar. Type II diabetes occurs when the body either does not produce enough insulin or does not use insulin normally (insulin resistance). Common symptoms of diabetes include frequent urination, unusual thirst, and extreme hunger. Use of some antiretroviral (ARV) drugs may increase the risk of diabetes.
See Related Term(s): Hyperglycemia, Insulin Resistance
Diabetes Mellitus
Also Known As: Diabetes
Directly Observed Therapy (DOT) (En español)
A method of drug administration in which a health care professional watches as a person takes each dose of a medication. Directly observed therapy (DOT) is used to ensure the person receives and takes all medications as prescribed and to monitor response to treatment. DOT is widely used to manage tuberculosis (TB) disease. In HIV treatment, DOT is sometimes called directly administered antiretroviral therapy (DAART).
See Related Term(s): Self-Administered Therapy
When an infection or disease has widely dispersed in a tissue, an organ, or the entire body.
Division of Acquired Immunodeficiency Syndrome (DAIDS) (En español)
A federal program that supports research on the following: how HIV is transmitted and causes disease; the development of therapies for HIV infection, its complications, and co-infections; and the development of vaccines and other prevention strategies.
See Related Term(s): National Institute of Allergy and Infectious Diseases
Also known as: Buffalo Hump
An accumulation of fat on the back of the neck between the shoulders. A dorsocervical fat pad may be due to use of some antiretroviral (ARV) drugs.
See Related Term(s): Lipodystrophy
The administration of individual doses of a medication as part of a medication regimen, usually expressed as quantity per unit of time. For example, a prescribed dosage might consist of 25 mg of a medication given 3 times a day for 6 days.
The quantity of a medication to be given at one time, or the total quantity of a medication administered during a specified period of time. For example, a patient might receive an initial medication dose of 50 mg, and, during the entire course of treatment, receive a total medication dose of 500 mg.
A type of clinical trial. In dose-ranging trials, different doses of a drug are tested. Trial results are compared to determine which dose is most safe and effective.
See Related Term(s): Clinical Trial
Dose-Response Relationship (En español)
The association between the dose of a drug and the body’s corresponding response to that dose.
Also known as: Drug Opposition
An interaction between two or more drugs that have opposite effects on the body. Drug antagonism may block or reduce the effectiveness of one or more of the drugs.
See Related Term(s): Drug Synergism
A group of drugs that share common properties, which may include a similar mechanism of action, chemical structure, or approved use. Antiretroviral (ARV) HIV drugs are classified into six drug classes on the basis of how each drug interferes with the HIV life cycle. These six classes include the nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs), fusion inhibitors, CCR5 antagonists, and integrase strand transfer inhibitors (INSTIs).
See Related Term(s): CCR5 Antagonist, Fusion Inhibitor, Integrase Strand Transfer Inhibitor, Life Cycle, Non-Nucleoside Reverse Transcriptase Inhibitor, Nucleoside Reverse Transcriptase Inhibitor, Protease Inhibitor
Also known as: Concentration
The amount of a drug in a given volume of blood plasma, measured as the number of micrograms per milliliter.
A change in a drug’s effect on the body when taken with certain other drugs, supplements, or food, or when taken together with certain medical conditions. A drug interaction may cause the drug to be less effective, cause adverse effects, or increase the action of the drug. Potential drug interactions are considered when selecting antiretroviral (ARV) drugs to include in an HIV treatment regimen.
See Related Term(s): Drug-Drug Interaction, Drug-Food Interaction
Also known as: Synergism, Synergy
An interaction between two or more drugs that causes the total effect of the drugs to be greater than the sum of the individual effects of each drug. A synergistic effect can be beneficial or harmful.
See Related Term(s): Drug Antagonism
A change in a drug’s effect on the body when the drug is taken together with a second drug. A drug-drug interaction can delay, decrease, or enhance absorption of either drug. This can make either or both of the drugs less effective or more active, or cause adverse effects.
See Related Term(s): Drug Antagonism, Drug Interaction, Drug Synergism
A change in a drug’s effect on the body when the drug is taken together with certain foods or beverages. Not all drugs are affected by food, and some drugs are affected by only certain foods. A drug-food interaction can delay, decrease, or enhance absorption of a drug. This can cause the drug to be less effective, cause adverse effects, or increase the action of the drug.
See Related Term(s): Drug Interaction
When a strain of HIV is sensitive to one or more antiretroviral (ARV) drugs. Antiretroviral therapy (ART) will likely be effective against a drug-susceptible strain of HIV.
See Related Term(s): Drug Resistance
Dual Energy X-Ray Absorptiometry (DXA) (En español)
Also known as: Bone Density Test
A test that uses low-dose x-rays to measure bone mineral density, including calcium content, in a section of bone. Dual energy x-ray absorptiometry (DXA) scans are used to detect osteoporosis and predict the risk of bone fracture.
See Related Term(s): Osteoporosis
Also known as: D/M-Tropic Virus, Mixed Tropic Virus
A strain of HIV that can enter and infect a host cell by binding to either the CCR5 or CXCR4 receptor on the host cell. To enter a host cell, HIV must first attach to a CD4 receptor, then attach to either the CCR5 or CXCR4 receptor, and finally fuse its membrane with the host cell membrane. HIV is usually R5-tropic (uses CCR5) during the early stages of infection, but the virus may later switch to using either only CXCR4 or both CCR5 and CXCR4.
See Related Term(s): CCR5, CXCR4, R5-Tropic Virus, X4-Tropic Virus
Abnormal levels of lipids (fats), including cholesterol and triglycerides, in the blood. Dyslipidemia can refer to either decreased or elevated levels of lipids. Dyslipidemia may be an adverse effect of some antiretroviral (ARV) drugs.
See Related Term(s): Hyperlipidemia
The development of precancerous changes in cells. Dyplasia can affect various parts of the body, including the cervix or prostate. The extent of dysplasia within body tissue can be mild (grade 1), moderate (grade 2), or severe (grade 3).
Difficult or labored breathing or shortness of breath.