In molecular biology, CD4 (
cluster of differentiation 4
) is a glycoprotein that serves as a co-receptor for the T-cell receptor (TCR). CD4 is found on the surface of immune cells such as T helper cells, monocytes, macrophages, and dendritic cells.
What does CD4 count mean?
A CD4 count is
a test that measures the number of CD4 cells in your blood
. CD4 cells, also known as T cells, are white blood cells that fight infection and play an important role in your immune system.
What does it mean if your CD4 count is high?
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.
What is a good CD4?
A normal CD4 count ranges
from 500–1,200 cells/mm
3
in adults and teens. In general, a normal CD4 count means that your immune system is not yet significantly affected by HIV infection. A low CD4 count indicates that your immune system has been affected by HIV and/or the disease is progressing.
What is the role of CD4 cells?
A key role of CD4
+
T cells is
to ensure optimal responses by other lymphocytes
. CD4
+
T cells are necessary as helpers to promote B cell antibody production and are often required for the generation of cytotoxic and memory CD8
+
T cell populations.
What food can increase CD4 count?
- Vitamin A and beta-carotene: dark green, yellow, orange, or red vegetables and fruit; liver; whole eggs; milk.
- B vitamins: meat, fish, chicken, grains, nuts, white beans, avocados, broccoli, and green leafy vegetables.
What are signs of low CD4 count?
Symptoms may include
fever, cough, difficulty breathing, weight loss, night sweats and fatigue
. It is most likely to occur when the CD4+ T cell count falls below 200 cells per cubic millimeter of blood.
How is CD4 calculated?
A CD4:CD8 ratio is calculated
by dividing the number of CD4+ T cells by the number of CD8+ T cells
; this ratio is usually greater than 1 in immunocompetent individuals [4]. However, in HIV infection, the CD4:CD8 ratio is usually less than 1.
How long can you live with a low CD4 count?
A person's CD4 count at the start of treatment remains one of the strongest indicators of life expectancy. The life expectancy between those whose CD4 count is less than 200 at the start of treatment is
8 years less
than those whose count is over 200 at the same time.
What is the lowest CD4 count?
The CD4 cell count of a person who does not have HIV can be anything between 500 and 1500. When the CD4 count of an adult falls below
200
, there is a high risk of opportunistic infections and serious illnesses.
Can stress lower your CD4 count?
Since prolonged stress can depress the immune system, stress is of particular importance for individuals living with HIV/AIDS. Studies have shown that
chronic stress, traumatic events, and depression can all lead to an increased viral load and decreased CD4
counts, and therefore, accelerate HIV disease progression.
What is a normal CD4 percentage?
A CD4% of 29% is about the same as a count of over 500 cells/mm
3
, but there is a wider range for higher values. The average normal CD4 percentage for someone who is HIV negative is about 40%. The normal range is anywhere from
about 25% to 65%
.
Is a CD4 count of 600 good?
A normal range for CD4 cells is between 600 and 1,500
. Usually, when a person with low CD4 cells starts HIV medicines, the CD4 cell count increases as the HIV virus is controlled. Most but not all people will experience an increase in CD4 cell with effective HIV treatment. The higher your CD4 count, the better.
Where is CD4 found?
The CD4 gene is located on
chromosome 12 in humans and on chromosome 6 in mice
(refer to Table 12-1). CD4 is a transmembrane glycoprotein of 55 kDa that is expressed as a single polypeptide chain on the surface of MHC class II-restricted T cells.
How many CD4 cells are in the human body?
CD4 counts show the robustness of the immune system. A healthy immune system normally has a CD4 count ranging from
500 to 1,600 cells per cubic millimeter of blood
(cells/mm3), according to HIV.gov. When a CD4 count is lower than 200 cell/mm3, a person will receive a diagnosis of AIDS.
How are CD4 cells activated?
Activation of CD4
+
T cells occurs
through the simultaneous engagement of the T-cell receptor and a co-stimulatory molecule
(like CD28, or ICOS) on the T cell by the major histocompatibility complex (MHCII) peptide and co-stimulatory molecules on the APC.
