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What Are CD4 T-Cells?

CD4 T-cells are white blood cells that fight off infections. HIV thrives off of attacking these cells. However, HIV treatments might help maintain the body’s T-cell count and keep a person healthy.

How CD4 T-Cells Work

CD4 T-cells (also known as CD4 T lymphocytes) help keep you healthy by attacking infection-causing pathogens. These powerful cells activate your body’s immune functions when they stimulate other cells in the immune system, including macrophages, B-cells (B lymphocytes), and CD8 T-cells (CD8 lymphocytes). Those cells work together to attack and eradicate viruses from the body.

CD4 T-Cells and HIV

HIV is a virus that weakens the immune system over time by destroying CD4 T-cells. People with HIV monitor their status according to their body’s CD4 T-cell count, which measures the number of these cells in the blood. If an HIV-positive person has a low CD CD4 T-cell count, his or her body will be less capable of fighting off infections or diseases.

A person with a healthy immune system typically has a CD4 count between 500 and 1,500 cells per cubic millimeter of blood. Medical providers make an AIDS diagnosis when an HIV-positive individual’s CD4 T-cell count falls below 200 cells per cubic millimeter of blood.

Antiretroviral Therapy

Antiretroviral therapy (ART) can prevent HIV from progressing to AIDS. This therapy reduces the amount of HIV in an affected individual’s blood (also known as viral load), which helps keep the virus from destroying CD4 T-cells.

ART is most effective when started as soon as possible after an HIV diagnosis. Consistent use can give HIV-positive individuals similar life expectancies as HIV-negative individuals. In addition to keeping viral load levels very low, ART reduces the risk of transmitting HIV sexually to an HIV-negative partner. Those who are HIV-negative can also take PrEP (pre-exposure prophylaxis) to reduce their risk of becoming infected from having sex with an HIV-positive partner.

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