HIV

Dementia

Chronic impairment of thinking (ie, loss of mental capacity) that affects a person's ability to function in a social or occupational setting.

See HIV-associated dementia (HAD).

Demyelination

Destruction, removal, or loss of the myelin sheath of a nerve or nerves.

Dendritic cells

Immune system cells that may initiate HIV infection by carrying the virus from the site of the infection to the lymph nodes, where other cells, such as CD4 T cells, become infected. Dendritic cells circulate through the body and bind to infectious agents in tissues, such as the skin and membranes lining the intestinal tract, lungs, and reproductive tract. Once in contact with CD4 T cells, they initiate an immune response to the virus.

Deoxyribonucleic acid (DNA)

The twisted double-stranded molecular chain found in genes within the nucleus of each cell. DNA carries the genetic information that enables cells to reproduce and transmit hereditary characteristics.

Desensitization

Gradually increasing the dose of a medicine in order to overcome severe reactions.

Diagnosis

The decision that a patient has a specific disease or infection, usually accomplished by evaluating clinical symptoms and laboratory tests.

Disseminated

Spread of a disease throughout the body.

DNA

See Deoxyribonucleic acid (DNA).

Dormant

Inactive infection that is still present in the body.

DOT

Directly observed therapy (short course). Treatment that is given under the observation of a health care worker.

Double-blind study

A clinical trial design in which neither the patient nor the study staff know which patients are receiving the experimental drug and which are receiving a placebo (or another therapy).

Drug resistance

The ability of some disease-causing infectious agents, such as bacteria and viruses, to adapt themselves, grow, and multiply even in the presence of drugs that usually kill them.

See Cross-resistance.

Drug-drug interaction

A change in the effect of a drug when administered with another drug. The effect may be an increase or a decrease in the action, or it may be an adverse effect that is not normally associated with either drug.

Dysplasia

Any abnormal development of tissues or organs.

Dyspnea

Difficult or labored breathing.