CD4 (cluster of differentiation 4) is a glycoprotein found on the surface of immune cells such as T helper cells, monocytes, macrophages, and dendritic cells.
It was discovered in the late 1970s and was originally known as leu-3 and T4 (after the OKT4 monoclonal antibody that reacted with it) before being named CD4 in 1984.[2] In humans, the CD4 protein is encoded by the CD4 gene.
CD4+ T helper cells are white blood cells that are an essential part of the human immune system. They are often referred to as CD4 cells, T-helper cells or T4 cells. They are called helper cells because one of their main roles is to send signals to other types of immune cells, including CD8 killer cells, which then destroy the infectious particle. If CD4 cells become depleted, for example in untreated HIV infection, or following immune suppression prior to a transplant, the body is left vulnerable to a wide range of infections that it would otherwise have been able to fight.
WHAT IS A CD4 COUNT AND WHY IS IT IMPORTANT?
A
CD4 count is a lab test that measures the number of CD4 cells in a
sample of your blood. It is an important indicator of how well your
immune system is working.
The CD4 count of a healthy adult/adolescent ranges from 500 cells/mm3 to 1,200 cells/mm3.
A very low CD4 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). (See Stages of HIV Infection.)
So,
during your regular check-ups, your HIV care provider will want to know
your CD4 count to help keep track of how healthy you are and whether
the virus has progressed in your body.
Your CD4 count is also used to help you and your HIV care provider decide when to start antiretroviral therapy (ART).
ART
involves taking a combination of HIV medicines (called an HIV regimen)
every day. It prevents HIV from multiplying and destroying your
infection-fighting CD4 cells. ART can’t cure HIV, but it can help you
live a longer, healthier life and reduce your risk of HIV transmission.
THE HIGHER YOUR CD4 COUNT, THE BETTER
When
the amount of HIV in your blood is lowered by ART, it allows the CD4
cells to reproduce and increase in number. The higher your CD4 count,
the better able you are to fight HIV and other infections.
ART
is recommended for everyone with HIV, but the urgency to start ART is
greater in people with low or rapidly falling CD4 counts. A falling CD4
count indicates that HIV is advancing and damaging your immune system.
After
you start ART, your HIV care provider will use your CD4 count as one
way to check how well your medication is working to monitor the
effectiveness of your HIV regimen. Your HIV care provider will also
monitor your CD4 count to determine whether it has fallen to a level at
which you might be at risk for certain opportunistic infections. In that
case, your HIV care provider may prescribe some additional medications
to prevent other infections.
Everyone should have a CD4 count soon after they are diagnosed with HIV. The result is used, with other factors, to decide when to start treatment. Guidelines recommend starting treatment at different CD4 counts cut offs depending on which country you live in.
All guidelines recommend that treatment should be started before the CD4 count falls to less than 200.
A few guidelines (including the UK), recommend treatment when the CD4 count is around 350 cells/mm3.
Many guidelines use a CD4 cut off of 500. This is based on reducing HIV transmission as well as health benefits to the person taking treatment.
Some guidelines in the US say that treatment could be started at any CD4 count, including when over 500.
Currently, it is unclear whether starting above 500 has any long-term clinical advantage over waiting until under 500 or under 350. Some studies report no difference, other suggest there may be a small difference.
CD4 counts should be tested every three months. Sometimes lack of resources mean it may be done every six months.
Some food that help to increase your cd4 count are as follows
Vitamin B12 deficiency has been associated with decreasing CD4+ cells, which are white blood cells that help fight infection in the body. Some studies have shown that without supplements, up to 95 percent of those with HIV may have B12 deficiencies. Vitamin B6 has also been shown to improve CD4+ cell counts.
According to the Mayo Clinic, vitamin B12 can be obtained from eating one chicken breast, one hard boiled egg, and one cup of plain non-fat yogurt daily.
Selenium
Selenium also helps strengthen the immune systems by creating antioxidants that protect the body from invaders that may damage cells. Eating foods and supplements with antioxidants are beneficial for HIV positive individuals. Beans, blueberries, blackberries, and cranberries have high levels of antioxidants.
In a study published in Archives of Internal Medicine, the supplement selenium was found to reduce the amount of HIV in the blood and increase CD4+ cell levels.
Participants who took 200 micrograms of selenium daily for nine months had a 12 percent decrease in viral loads. Participants in the control group, who were not given selenium, experienced increased viral loads and decreased CD4 levels in the same nine month period of time.
