From the Guidelines
The CD4/CD8 ratio is not a necessary measurement for clinical decision making in HIV patients, as stated in the 2013 update by the HIV Medicine Association of the Infectious Diseases Society of America 1. This recommendation is based on high-quality evidence and suggests that the measurement of the CD8 cell count and the ratio of CD4 cells to CD8 cells is unnecessary. The primary focus should be on monitoring CD4 cell counts and percentages to assess immune function and determine the need for antiretroviral therapy or prophylaxis against opportunistic infections 1. Some key points to consider when monitoring HIV patients include:
- CD4 cell counts may be affected by various medications and intercurrent illnesses, so caution should be applied when interpreting these counts 1.
- The CD4 cell percentage can also be used to assess immune function and is somewhat less variable than the absolute count 1.
- Total CD4 cell counts of 200 and 500 cells/µL generally correspond to CD4 cell percentages of 14% and 29%, respectively 1.
- In children aged <5 years, the CD4 percentage is generally preferred for monitoring immune status due to more variability in the absolute count with age 1.
From the Research
CD4/CD8 Ratio Overview
- The CD4/CD8 ratio is a measure of the balance between two types of T cells in the immune system, CD4 and CD8 cells.
- A low CD4/CD8 ratio has been linked to immunosenescence, a state of immune system decline associated with aging, and is a predictor of mortality in the general population 2, 3.
Clinical Significance of CD4/CD8 Ratio
- In HIV-infected individuals, a low CD4/CD8 ratio is associated with an increased risk of serious non-AIDS-related events, such as non-AIDS malignancies, cardiovascular disease, and end-stage kidney disease 2.
- The CD4/CD8 ratio provides additional information to CD4 counts and nadir CD4 in treated HIV-infected individuals, as it is independently associated with the risk of non-AIDS-related morbidity and mortality 2.
- A low CD4/CD8 ratio may represent the combined effects of inflammation and immunological changes called "inflammaging" 3.
Factors Influencing CD4/CD8 Ratio
- Immune activation, T cell maturation markers, and cellular HIV-1 DNA levels can influence CD4+ T cell recovery during suppressive antiretroviral therapy 4.
- Antiretroviral therapy (ART) can reduce T-cell activation and immune exhaustion markers in HIV controllers, leading to a potential improvement in quality of life 5.
- However, plasma anti-CD4 IgG levels are not associated with poor immune recovery in people with HIV initiating antiretroviral therapy 6.
Implications for HIV Treatment and Management
- The CD4/CD8 ratio may be a useful marker for monitoring immune dysfunction and viral reservoir size in long-term treated HIV-positive adults 3.
- ART may have clinical benefits in HIV controllers by reducing T-cell activation and improving markers of immune exhaustion 5.
- Further research is needed to fully understand the mechanisms underlying the CD4/CD8 ratio and its implications for HIV treatment and management.