CD4 cells (sometimes called T-cells, T-lymphocytes, or helper cells) are white blood cells that play an important role in the immune system. Your CD4 cell count gives you an indication of the health of your immune system – your body’s natural defence system against pathogens, infections and illnesses.
Your CD4 cell count is the measurement of the number of blood cells in a cubic millimetre of blood (a very small blood sample). It is not a count of all the CD4 cells in your body. A higher number indicates a stronger immune system.
- The CD4 cell count of a person who does not have HIV can be anything between 500 and 1500.
- People living with HIV who have a CD4 count over 500 are usually in pretty good health.
- People living with HIV who have a CD4 cell count below 200 are at significant risk of developing serious illnesses. While HIV treatment is recommended for all people living with HIV, it is especially important for people with low CD4 counts.
If you have HIV and do not take HIV treatment, your CD4 count will fall over time. The lower the CD4 cell count, the greater the damage to the immune system and the greater the risk of illness.
When you take HIV treatment, your CD4 count should gradually increase.