What is CD4 and CD4 Molecule and What Are CD4 Tests For?

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CD4 Cell and CD4 Molecule

What is CD Cell and CD4 Molecule?

This is, I would say, the question of one million pounds sterling!

Because it is the name of the CD4 Cells, the cells that express the CD4 molecule, indispensable for the HIV infection

What is CD4 And ​​What Are CD4 Tests For? And What Is A CD4 Molecule

CD4 is a molecule that is expressed on the surface of some T cells, macrophages, monocytes and the dendritic cell. It is a monomeric 59k glycoprotein containing four immunoglobulin-like domains. (Wikipedia - CD4)

CD4 cells are a type of lymphocyte (white blood cell).

They are an important part of the immune system.

CD4 cells are sometimes referred to as T cells. There are two main types of T cells. T-4 Cells, also called CD4, are “Auxiliary Cells".

They led the attack on infections. T-8 (CD8 cells) are "suppressor cells" of the immune response. CD8 cells can also be "killers" that kill cancer cells and cells infected with viruses.

It is important to note, for this is a common and erroneous doubt or self-definition:

Hemograms, even with "leukocyte drops" do not serve as an indicator of immune deficiency.

These cells look for and characterize other cells and infectious agents for specific proteins on the cell surface.

A T-4 cell is a T cell with CD4 molecules on its surface. This type of T cell is also called a “positive cell”, CD4 or CD4 cell.


HIV often infects CD4 cells. The virus becomes part of the cells, and when it multiplies to fight an infection, they make more copies of HIV.

When someone is infected with HIV but has not started treatment, the number of CD4 cells is decreasing. This is a sign that the immune system is being weakened. The lower the CD4 cell count, the greater the likelihood of this person becoming ill.

There are millions of different families of CD4 cells. Each family is designed to fight a specific type of germ. When HIV decreases the number of CD4 cells, some of these families can be eradicated. You may lose the ability to fight off germs whose families have been designed. If this happens, you can develop a opportunistic infection (See Fact Sheet 500).


A small sample of blood is taken. Blood is tested for count of various cell types. CD4 cells are not counted directly. Instead, the lab does a calculation based on total white blood cells and the proportion of cells that are CD4. Therefore, the CD4 count is not accurate.

The current treatment (see Sheet of fact 404) suggests monitoring CD4 through testing every 3 to 6 months when initiating antiretroviral therapy (ART, see Sheet of fact 403). Since the treatment increases the levels of CD4 to high levels, the test should be done every 6 to 12 months.

What are the factors that influence the CD4 cell count?

The value of CD4 cells varies around batches. Time of day, fatigue and stress can affect the test results. It is best to have blood drawn at the same time of day for each cell testPay 937884 CD4 and to use the same laboratory.
Infections can have a major impact on the CD4 cell count. When your body fights an infection, the number of white blood cells (lymphocytes) rise. And the CD4 and CD8 cell count goes up too high. Vaccination may cause the same effects. Do not check your CD4 cells until a couple of weeks after recovering from an infection or being vaccinated.

How are the results of the CD4 test reported?

Tests of CD4 cells are usually reported as the number of cells in a cubic millimeter of blood or mm3. Normal counts are usually between 500 and 1600.

Because the CD4 cell count is so variable, some healthcare providers prefer to look at the percentage of CD4 cells. If your CD reports test 4% = 34%, which means that 34% of your lymphocytes were CD4 cells. This percentage is more stable than the number of CD4 cells.

A count of CD4 below 200 indicates severe damage to the immune system. It is a sign of AIDS in people with HIV infection. Although the percentage of CD4 may be a better predictor of progression of HIV disease than the CD4 count, the CDXUMUMX count is used to decide when to start treatment.

The doctor who triggered the situation of dread that I have accompanied reminds me of something that, who has more than 35 years certainly know what it is:

CD4 Is A Type Of Lymphocyte

The normal range is somewhere between 30% and 60%. Different laboratories use different ranges. There are no guidelines for treatment of decisions based on percentages of CD4. However, a percentage of CD4 below 14 is a definition of AIDS.

What do the numbers mean?

The CD4 cell count is a key measure of immune system health. The lower the count, the greater the damage caused by HIV. Those who have less than 200 CD4 cells or a percentage less than 14%, are considered to be AIDS patients according to the US Centers for Disease Control and also the National STD / AIDS and Viral Hepatitis Program of the Ministry of Health.

CD4 counts are used in conjunction with viral load to estimate how long someone will stay healthy. See Sheet of fact 125 for more information about the viral load test.

CD4 counts are also used to indicate when to start certain types of drug treatment:

When to start the drug to prevent opportunistic infections:

Most health care providers prescribe medications to prevent opportunistic infections at the following levels of CD4:
Less than 200: Pneumocystis pneumonia (PCP, see Sheet of fact 515)
Less than 100: toxoplasmosis (see Sheet of fact 517) and cryptococcosis (see Sheet of fact 503)
Less than 50: Mycobacterium avium complex (MAC, see Sheet of fact 514)

Monitoring treatment success:

With the success of ART, CD4 counts can sometimes rise rapidly. Other times they may rise slowly. If the CD4 count is low when ART is started, CD4 counts may not recover to normal levels. {Translator's note, not to mention me, I quote Beatriz Pacheco and Beto Volpe, whose clinical histories, if read by an unsuspecting doctor, could at some point say that 'these people are dead' they actually waste, give , sell, rent and squander health with the success of their treatments which, at the time of their respective beginnings, were not “very promising”]. In addition, if CD4 counts fall while you are on ART, it may be occurring. therapeutic failure and one of the reasons for this may be due to unpunctual application of the drugs; maintain your adherence to treatment spartan. Higher CD4 counts are better. However, a normal CD4 count does not guarantee a normal immune system. Continuous monitoring The current treatment directive (available at http://aidsinfo.nih.gov/guidelines) suggests that if a patient maintains an undetectable viral load, CD4 counts can be done once a year or even less frequently.


Now that people with AIDS live longer, there is more research into other causes of illness and death. These are non-AIDS-related causes of death, which include liver disease, non-AIDS-related cancer, and heart disease. Globally, these deaths are decreasing. However, research shows a clear link between the low CD4 count and the risk of death.

Bottom line

Because they are an important indicator of immune system strength, a US treatment guidelines fact sheet suggests that CD4 counts should be monitored every six to twelve months for people whose ART has functioned to maintain a high level. of CD4 cells.

Editor's note: On my last visit to the AIDS House, my Doctor (With "M", capital) gave me similar instructions, and although I was a little upset with the government, I was sure Angela wouldn't do that. not under strong coercion and accepted peacefully. Editing the text now, I see that I was right about my considerations by the person who studied and has devoted his days to keeping me and about four hundred other patients alive and healthy.

Translated and edited by Claudio Souza the original Fact Sheet 124 CD4 Cell Tests on 06 April 2016 Reviewed by Mara Macedo


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8 Reviews

Cilas 21/04/2016 at 02:00

God bless the researches of these doctors, we are suffering a lot with this pain, please show us the cure.

Cláudio S. So 21/04/2016 at 11:03


Did the Exam give HIV Reagent? Just sit down. Welcome! 23/07/2017 at 16:45

[...] called the Viral Load, to assess the amount of HIV in your blood and one called the CD4 cell count, to evaluate how your system is [...]

Morgana Laís 17/08/2017 at 09:49

I loved this post, it was very relevant to me!

Miriam 25/08/2017 at 18:24

I'm undetectable for a year, but CD4 and CD8 are still low. My last CD4 result was 88
Being that 74 was in the previous result.
I do not know what to do, I take vitamins, I eat very well, I exercise. Sorry it was just an outburst. But the fight continues.

Claudio Santos 27/08/2017 at 18:52

Miriam, you have reason to be worried, and that worries me too.
The fact is that you have a serious immune deficiency and I ask if the treating physician has entered with at least one broad-spectrum antibiotic like chemoprophylaxis.
If he / she did not make it possible for the person to read this and give me news. Thank you

Fernando 20/12/2017 at 16:17

I went to the doctor hj, and the result for the second time was DETECTABLE, She requested again tests of viral load and CD4. But I make irregular use of cocaine. Could this be influencing the results?

Cláudio Souza do Soropositivo.Org 22/12/2017 at 09:21

What exam?


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