HIV CD 4 Count

What are CD 4 Cells?

CD 4 cells or T-cells are a type of white blood cells that play a major role in protecting your body from infection. They send signals to activate your body’s immune response when they detect “intruders,” like viruses or bacteria.

Once a person is infected with HIV, the virus begins to attack and destroy the CD 4 cells of the person’s immune system. HIV uses the machinery of the CD 4 cells to multiply (make copies of itself) and spread throughout the body.

This process is called the HIV life cycle.

What is a CD 4 Count?

A CD 4 count is a lab test that measures the number of CD 4 T lymphocytes (CD 4 cells) in a sample of your blood.

Normal CD count:
It is an important indicator of how well your immune system is working. The CD 4 count of a healthy adult/adolescent ranges from 500 cells/mm3 to 1,200 cells/mm3. A very low CD 4 count (less than 200 cells/mm3) is one of the ways to determine whether a person living with HIV has progressed to stage 3 infection (AIDS).

HIV attacks the immune system by placing the virus’s own genetic material in some cells, which are an important part of the immune system. These cells would normally produce new cells for the immune system, but because HIV has placed its genetic material into the cell, the cell will instead create new HIV virus.Photo: John Wu /Flickr