Table of ContentsView AllTable of ContentsCD4 and CD8 T Cells InteractionCD4/CD8 RatioHealth Conditions With Low RatioHealth Conditions With High RatioHow Often to Get Tested

Table of ContentsView All

View All

Table of Contents

CD4 and CD8 T Cells Interaction

CD4/CD8 Ratio

Health Conditions With Low Ratio

Health Conditions With High Ratio

How Often to Get Tested

T cells are a type of white blood cell that is central to your immune defense. There are four types which serve different functions:

The CD4/CD8 ratio is one of the blood tests used to monitor yourimmune systemif you havehuman immunodeficiency virus (HIV). It compares the proportion of so-called “helper"CD4 T cellsto “killer” CD8 T cells, the value of which can help predict the likely course of the disease.

This article will guide you through how CD4 and CD8 cells interact, what the CD4/CD8 ratio tells us, some conditions in which the ratio can be either high or low, and how often you may need to be tested to monitor an illness.

Bernd Lauter / Getty Images

Blood test, test tubes in a centrifuge

How CD4 and CD8 T Cells Interact

CD4 and CD8 are simply two different types of glycoprotein found on the surface of T cells and other lymphocytes (the class of white blood cells central to the immune system).

What is a normal CD4/CD8 ratio?A CD4/CD8 ratio is considered normal when the value is between 1.0 and 4.0. In a healthy individual, that translates to roughly 30%–60% CD4 T cells in relationship to 10%–30% CD8 T cells.

What is a normal CD4/CD8 ratio?

A CD4/CD8 ratio is considered normal when the value is between 1.0 and 4.0. In a healthy individual, that translates to roughly 30%–60% CD4 T cells in relationship to 10%–30% CD8 T cells.

WhenHIV therapyis initiated promptly, the ratio will generally return to normal. However, if the treatment is delayed until the immune system is seriously damaged, the body’s ability to create new CD4 T cells will weaken. If this happens, the ratio may never rise much above 1.0.

What the CD4/CD8 Ratio Tells Us

The prognostic (predictive) value of CD4/CD8 is considered less relevant to the management of HIV than it was 20 years ago. Back then, there were fewer, less effective drugs available to treat HIV. While the value can still help us determine the age of the infection and yourrisk of mortality, changes have been made in recent years.

With that being said, increasing focus has been placed on the use of the CD4/CD8 ratio in people withlong-term HIV infection, Recent studies have suggested that people with a low CD4/CD8 ratio who have been on treatment for years are at an increased risk of non-HIV-related illness and death.

There are several other areas in which the CD4/CD8 ratio may also be important. In epidemiological research, the ratio can be used to measurevirulence(the ability to cause disease) of HIV in different populations or over specific periods.

The CD4/CD8 ratio test is most frequently used to monitor HIV status. However, it can also be used to diagnose and assess other conditions.

Which Health Conditions Have a Low CD4/CD8 Ratio?

Aside from in HIV/AIDS, the CD4/CD8 ratio can be low in conditions including:

Which Health Conditions Have a High CD4/CD8 Ratio?

The CD4/CD8 ratio can be high in conditions including:

For people newly diagnosed with HIV, routine blood monitoring should be performed at the time of entry into care and then every three to six months afterward. This includes theCD4 countand viral load. Once you have been on treatment and have maintained an undetectable viral load for a least two years:

Summary

The CD4/CD8 ratio is a blood test used to monitor the immune systems of people with HIV and other disorders. CD4 and CD8 cells react correspondingly to each other and their ratio (whether low or high) can indicate certain illnesses like HIV, multiple sclerosis, or blood cancer. CD4/CD8 ratio testing is typically done regularly, from the first sign of an illness, to monitor immune response.

7 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Okoye AA, Picker LJ.CD4(+) T-cell depletion in HIV infection: mechanisms of immunological failure.Immunol Rev. 2013;254(1):54-64. doi:10.1111/imr.12066Eisinger RW, Dieffenbach CW, Fauci AS.HIV Viral Load and Transmissibility of HIV Infection: Undetectable Equals Untransmittable.JAMA.2019;321(5):451-452. doi:10.1001/jama.2018.21167Seng R, Goujard C, Krastinova E, et al.Influence of lifelong cumulative HIV viremia on long-term recovery of CD4+ cell count and CD4+/CD8+ ratio among patients on combination antiretroviral therapy.AIDS. 2015;29(5):595-607. doi:10.1097/QAD.0000000000000571Li CX, Li YY, He LP, et al.The predictive role of CD4+cell count and CD4/CD8 ratio in immune reconstitution outcome among HIV/AIDS patients receiving antiretroviral therapy: an eight-year observation in China.BMC Immunol. 2019;20(1):31. Published 2019 Aug 28. doi:10.1186/s12865-019-0311-2Clinicalinfo.HIV.gov.Guidelines for the Use of Antiretroviral Agents in Pediatric HIV Infection.MedlinePlus.CD4 Lymphocyte Count.OSF Healthcare.Tests & Procedures - CD4-CD8 Ratio.Additional ReadingMahnke, Y.; Greenwald, J.; DerSimonian, R.; et al.Selective expansion of polyfunctional pathogen-specific CD4 T cells in HIV-1–infected patients with immune reconstitution inflammatory syndrome.Blood.2012; 119(13):3105-3112. DOI: 10.1182/blood-2011-09-380840.Sources:

7 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Okoye AA, Picker LJ.CD4(+) T-cell depletion in HIV infection: mechanisms of immunological failure.Immunol Rev. 2013;254(1):54-64. doi:10.1111/imr.12066Eisinger RW, Dieffenbach CW, Fauci AS.HIV Viral Load and Transmissibility of HIV Infection: Undetectable Equals Untransmittable.JAMA.2019;321(5):451-452. doi:10.1001/jama.2018.21167Seng R, Goujard C, Krastinova E, et al.Influence of lifelong cumulative HIV viremia on long-term recovery of CD4+ cell count and CD4+/CD8+ ratio among patients on combination antiretroviral therapy.AIDS. 2015;29(5):595-607. doi:10.1097/QAD.0000000000000571Li CX, Li YY, He LP, et al.The predictive role of CD4+cell count and CD4/CD8 ratio in immune reconstitution outcome among HIV/AIDS patients receiving antiretroviral therapy: an eight-year observation in China.BMC Immunol. 2019;20(1):31. Published 2019 Aug 28. doi:10.1186/s12865-019-0311-2Clinicalinfo.HIV.gov.Guidelines for the Use of Antiretroviral Agents in Pediatric HIV Infection.MedlinePlus.CD4 Lymphocyte Count.OSF Healthcare.Tests & Procedures - CD4-CD8 Ratio.Additional ReadingMahnke, Y.; Greenwald, J.; DerSimonian, R.; et al.Selective expansion of polyfunctional pathogen-specific CD4 T cells in HIV-1–infected patients with immune reconstitution inflammatory syndrome.Blood.2012; 119(13):3105-3112. DOI: 10.1182/blood-2011-09-380840.Sources:

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Okoye AA, Picker LJ.CD4(+) T-cell depletion in HIV infection: mechanisms of immunological failure.Immunol Rev. 2013;254(1):54-64. doi:10.1111/imr.12066Eisinger RW, Dieffenbach CW, Fauci AS.HIV Viral Load and Transmissibility of HIV Infection: Undetectable Equals Untransmittable.JAMA.2019;321(5):451-452. doi:10.1001/jama.2018.21167Seng R, Goujard C, Krastinova E, et al.Influence of lifelong cumulative HIV viremia on long-term recovery of CD4+ cell count and CD4+/CD8+ ratio among patients on combination antiretroviral therapy.AIDS. 2015;29(5):595-607. doi:10.1097/QAD.0000000000000571Li CX, Li YY, He LP, et al.The predictive role of CD4+cell count and CD4/CD8 ratio in immune reconstitution outcome among HIV/AIDS patients receiving antiretroviral therapy: an eight-year observation in China.BMC Immunol. 2019;20(1):31. Published 2019 Aug 28. doi:10.1186/s12865-019-0311-2Clinicalinfo.HIV.gov.Guidelines for the Use of Antiretroviral Agents in Pediatric HIV Infection.MedlinePlus.CD4 Lymphocyte Count.OSF Healthcare.Tests & Procedures - CD4-CD8 Ratio.

Okoye AA, Picker LJ.CD4(+) T-cell depletion in HIV infection: mechanisms of immunological failure.Immunol Rev. 2013;254(1):54-64. doi:10.1111/imr.12066

Eisinger RW, Dieffenbach CW, Fauci AS.HIV Viral Load and Transmissibility of HIV Infection: Undetectable Equals Untransmittable.JAMA.2019;321(5):451-452. doi:10.1001/jama.2018.21167

Seng R, Goujard C, Krastinova E, et al.Influence of lifelong cumulative HIV viremia on long-term recovery of CD4+ cell count and CD4+/CD8+ ratio among patients on combination antiretroviral therapy.AIDS. 2015;29(5):595-607. doi:10.1097/QAD.0000000000000571

Li CX, Li YY, He LP, et al.The predictive role of CD4+cell count and CD4/CD8 ratio in immune reconstitution outcome among HIV/AIDS patients receiving antiretroviral therapy: an eight-year observation in China.BMC Immunol. 2019;20(1):31. Published 2019 Aug 28. doi:10.1186/s12865-019-0311-2

Clinicalinfo.HIV.gov.Guidelines for the Use of Antiretroviral Agents in Pediatric HIV Infection.

MedlinePlus.CD4 Lymphocyte Count.

OSF Healthcare.Tests & Procedures - CD4-CD8 Ratio.

Mahnke, Y.; Greenwald, J.; DerSimonian, R.; et al.Selective expansion of polyfunctional pathogen-specific CD4 T cells in HIV-1–infected patients with immune reconstitution inflammatory syndrome.Blood.2012; 119(13):3105-3112. DOI: 10.1182/blood-2011-09-380840.Sources:

Mahnke, Y.; Greenwald, J.; DerSimonian, R.; et al.Selective expansion of polyfunctional pathogen-specific CD4 T cells in HIV-1–infected patients with immune reconstitution inflammatory syndrome.Blood.2012; 119(13):3105-3112. DOI: 10.1182/blood-2011-09-380840.

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