What to Know About the CD4:CD8 Ratio Test (2024)

CD4 and CD8 are two types of white blood cells in your blood. CD4 cells are also called T-helper cells, T-suppressor cells, and cytotoxic T-cells. They help the body fight infections. CD8 cells are also called cytotoxic T-lymphocytes. They help fight cancer and germs that live inside your cells (intracellular pathogens). The human immunodeficiency virus (HIV) chiefly targets CD4 cells. A reduced number of these cells and a change in the CD4:CD8 ratio are signs of HIV infection. The CD4:CD8 ratio helps your physician judge disease activity and your response to treatment.

CD4 Cell Count

The CD4 cell count is a good measure of the activity of the HIV infection and the success of the treatment. Normal CD4 numbers in the blood range between 500 to 1200 per cubic millimeter. The normal range for CD8 is 150 to 1000 per cubic millimeter. A CD4:CD8 ratio of more than 1.0 is considered normal. A CD4 count below 200 per cubic millimeters shows that you have acquired immunodeficiency syndrome (AIDS). Low CD4 counts are also seen in bone marrow suppression because of chemotherapy, long-standing infections, and some types of anemia.

Once you start ART (antiretroviral therapy, a combination of antiviral medicines), your CD4 cell count increases gradually. Your physician will get your CD4 count tested every 3 to 6 months. The return of the CD4 count to normal levels (500 per cubic millimeter) is a sign that the HIV infection is under control.

CD4:CD8 Ratio

Traditionally, CD4 counts and viral loads were used to judge the body's response to HIV treatment. But you may be experiencing a weakening of your immune system despite having a normal CD4 count. The CD4:CD8 ratio is more useful in judging the immune system's function. People with HIV and a low CD4:CD8 ratio have increased frailty and mortality.

The total CD4 number, their proportion (CD4 percentage), and their ratio to CD8 cells (CD4:CD8 ratio) are tests used to guide HIV treatment. A CD4:CD8 ratio of more than 1.0 is considered normal. A low ratio (more CD8 cells than CD4) is often seen in HIV infections.

The CD4:CD8 ratio test judges the strength of your immune system. It also tells your physician if you are at risk for opportunistic infections like pneumocystis pneumonia. Your physician may want to protect you by prescribing some medicines.

A low CD4:CD8 ratio during treatment predicts that the virus hasn't been completely removed from your blood. If treatment begins early in the course of an HIV infection, your CD4:CD8 ratio is likely to become normal in about 6 years. Late and irregular treatments are associated with this test remaining abnormal.

The currently used antiretroviral drugs are very effective. Viral loads become undetectable in the blood, and the CD4 count returns to normal with some years of treatment. But several complications of AIDS still happen. The CD4:CD8 ratio is more accurate at predicting the risk of AIDS-associated cancers such as Kaposi's sarcoma and non-Hodgkins lymphoma.

Low CD4:CD8 Ratio

This test is most often done to assess HIV infection status, but it also helps in the diagnosis and monitoring of other diseases:

  • Infectious mononucleosis
  • Chronic lymphocytic leukemia
  • Hodgkin disease (lymphoma)
  • Aplastic anemia
  • Multiple sclerosis
  • Myasthenia gravis
  • DiGeorge syndrome
  • Organ transplantation

High CD4/CD8 Ratio

The CD4:CD8 ratio can be high in:

  • Major bacterial infection
  • Viral infection
  • Some types of blood cancer

Testing for HIV

HIV is the most frequent reason for abnormal CD4:CD8 ratios. But this test should not be used to diagnose an HIV infection. Your physician will ask for antigen, antibody, or nucleic acid tests to diagnose an HIV infection.

Once your physician has diagnosed HIV, they will start treatment. The CD4:CD8 ratio test and the CD4 cell count are helpful in assessing the progress of the infection. Your physician uses these tests to know if your infection is under control and whether you are at risk of complications.

Another way to assess the progress of the HIV infection is to test the viral load. This measures the amount of HIV in your blood. A high viral load means that your immune system is not fighting the virus well. Your physician will test your viral load every 4 to 6 months, and will also test it if they change your medicines.

High CD8 Counts

Your doctor monitors CD8 counts frequently while you are on treatment for HIV. If your CD8 count is high, it means your viral load is low. Your CD4 count is likely to return to normal levels. CD8 cells are important in the body's defense against HIV, and high CD8 count means that your body is effectively controlling the infection.

If your CD8 counts have been low or normal for some time and then become high, your physician is warned that treatment failure is about to happen. The CD8 cells increase in response to increasing viral load. Treatment failures happen in 20% to 40% of people on ART. Your doctor will ask if you're regular about taking your medicines, and consider other causes of treatment failure.

HIV infection was a deadly disease a few decades ago. People with untreated AIDS usually die within three years. With treatment and proper monitoring, people with HIV can live long and productive lives. CD4 counts, viral loads, and the CD4:CD8 ratio tests help your physician judge your disease control and fine-tune your treatment. Getting these tests done regularly will help you keep the infection under control.

What to Know About the CD4:CD8 Ratio Test (2024)


What does CD4:CD8 ratio tell you? ›

This test looks at the ratio of CD4 cells to CD8 cells. The ratio tells your healthcare provider how strong your immune system is and helps predict how likely you are to develop an infection.

What autoimmune disease has a high CD4:CD8 ratio? ›

Since 1980 it has been recognized that the proportion and number of CD8+ T cells in the peripheral blood are decreased and that the CD4/CD8 ratio is increased in patients with autoimmune diseases, including multiple sclerosis (MS) [16–21], rheumatoid arthritis (RA) [22, 23], SLE [24, 25], Sjögren's syndrome [25, 26], ...

What is the ratio of CD4+ to CD8+ cells in healthy human beings? ›

The CD4/CD8 ratio is calculated by dividing the CD4 cell count by the CD8 cell count. For example a ratio of 2 would indicate that there are 2 CD4 cells for every 1 CD8 cell. A normal ratio is between 1 and 3.

How to understand CD4 results? ›

What do the results mean?
  1. Normal CD4 count for healthy adults and teens: 500 to 1,200 cells per cubic millimeter.
  2. Low CD4 count: Below 500 cells per cubic millimeter. ...
  3. High CD4 Count: Counts above the normal range may be sign of an infection or a blood cancer.
Aug 22, 2022

What are signs of low CD4 count? ›

Symptoms of low CD4 count
  • Candidiasis. Tongue changes (white patches, redness) Mouth pain. Taste changes. Poor appetite. vagin*l yeast infections.
  • Herpes simplex virus. Sores on the mouth, genitals or around the anus.
  • Salmonella. Fever. Diarrhea.
  • Toxoplasmosis. Headache. Vision changes. Confusion. Seizures.
Jan 18, 2024

What is a high CD4:CD8 ratio for sarcoidosis? ›

A CD4+/CD8+ ratio >3.5 in vitreous fluid has a high diagnostic value in diagnosing ocular sarcoidosis according to Kojima et al11 In previously published work, the CSF CD4+/CD8+ ratio in healthy controls and multiple sclerosis has been reported to 2.23 and 2.47, respectively.

What is the reversed CD4 to CD8 ratio? ›

"A low or inverted CD4/CD8 ratio is an immune risk phenotype and is associated with altered immune function, immune senescence, and chronic inflammation in both HIV-infected and uninfected populations [8–11]. The prevalence of an inverted CD4/CD8 ratio increases with age.

What autoimmune diseases are mediated by CD8? ›

In addition to the protective function of CD8+ T cells in viral infections and tumors, evidence primarily from studies in the experimental autoimmune encephalomyelitis (EAE), multiple sclerosis (MS), systemic lupus erythematosus (SLE), type 1 diabetes (T1D), rheumatoid arthritis (RA), and vitiigo have been manifested ...

What CD4 count is considered immunocompromised? ›

For example, if your CD4 cell count is 200 or below, you are at risk of developing some serious illnesses and infections. Your doctor should recommend that you start HIV treatment urgently, without delay.

What is the CD4:CD8 ratio for lymphoma patients? ›

Normally, the approximate mean CD4/CD8 ratio in bone marrow is 1.0,45 in blood 1.5,46 and in cadaverous normal lymph nodes 3.3. In the present study, the mean CD4/CD8 ratio was normal (1.0) in bone marrows without lymphoma involvement but high (1.4) in bone marrows with lymphoma.

What is the CD4:CD8 ratio in car T? ›

A CAR+CD4+ /CD8+ ratio higher than the cut point of 1.12 was associated with an increased risk of treatment failure at M3 (OR 23.3, p = 0.012) and M6 (OR 10, p = 0.028). The median 6-month PFS was 76% for patients with a ratio lower than 1.12% vs. 31% for the others.

What is the normal CD4 count for a healthy person? ›

The CD4 count normal range is 500 to 1500 cell/mm^3. If a patient is left untreated, levels can drop below 200 cells/mm^3, which is one indication for the diagnosis of AIDS.

How to interpret CD4:CD8 ratio? ›

Normal CD4 numbers in the blood range between 500 to 1200 per cubic millimeter. The normal range for CD8 is 150 to 1000 per cubic millimeter. A CD4:CD8 ratio of more than 1.0 is considered normal. A CD4 count below 200 per cubic millimeters shows that you have acquired immunodeficiency syndrome (AIDS).

What is the CD4:CD8 ratio for autoimmune disease? ›

The CD4+/CD8+ ratio in the peripheral blood of healthy adults and mice is about 2:1, and an altered ratio can indicate diseases relating to immunodeficiency or autoimmunity. An inverted CD4+/CD8+ ratio (namely, less than 1/1) indicates an impaired immune system.

Which food increases CD4 count? ›

Increase intake of beans, soy products, lentils, peas, groundnuts, peanut butter and seeds, such as sunflower and sesame. Include all forms of meat, poultry, fish and eggs as often as possible.

What are CD4 and CD8 markers? ›

They are types of white blood cells that fight infection, and they play an important role in your immune system function. CD4 and CD8 cells are made in the bone marrow, and mature in the thymus gland, a small gland found in the upper chest.

What does it mean if CD4 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 does it mean when CD8 POS lymph is high? ›

An elevated percentage of CD8+ positive lymphocytes (% CD8+ Pos. Lymph.) typically indicates an increase in the proportion of a specific type of immune cell called CD8+ T cells in the bloodstream or in a tissue sample, such as from a blood test or a biopsy.

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