From the Guidelines
An elevated CD4:CD8 ratio is not a significant factor in clinical decision making, as stated in the 2013 update by the HIV Medicine Association of the Infectious Diseases Society of America 1. When considering the implications of an elevated CD4:CD8 ratio, it's essential to understand that this measurement is not typically used in clinical practice due to its limited utility in guiding treatment decisions.
- The CD4 cell count with percentage is a crucial initial assessment upon initiation of care, especially for individuals infected with HIV, as it provides valuable information about the immune system's status 1.
- However, the measurement of the CD8 cell count and the ratio of CD4 cells to CD8 cells is deemed unnecessary by clinical guidelines, indicating that an elevated ratio does not directly influence clinical management 1. Key points to consider in the context of an elevated CD4:CD8 ratio include:
- The substantial variation in CD4 cell counts, particularly during acute illnesses or due to the effects of various medications and intercurrent illnesses 1.
- The preference for using CD4 cell percentage over absolute counts in certain situations, such as in children under 5 years old, due to its lesser variability 1. Given the current evidence, the focus should be on the absolute CD4 cell count and percentage, rather than the CD4:CD8 ratio, for assessing immune function and guiding clinical decisions 1.
From the Research
CD4:CD8 Ratio Significance
The CD4:CD8 ratio is a marker used to evaluate the immune system function. An elevated CD4:CD8 ratio has been associated with various clinical outcomes and immune responses. The following points summarize the significance of an elevated CD4:CD8 ratio:
- In the context of HIV infection, a low CD4:CD8 ratio has been linked to ageing, inflammation, and immunosenescence, and is a predictor of mortality in the general population 2.
- An elevated CD4/CD8 ratio has been reported in patients with Hodgkin lymphoma, but it is a nonspecific finding that can also be seen in reactive and lymphoproliferative disorders 3.
- In HIV-coinfected adults, the CD4/CD8 ratio predicts the cellular immune response to acute hepatitis C, with a higher ratio associated with increased liver damage 4.
- In patients with advanced HIV infection, the CD4:CD8 ratio changes over time, with a rapid increase in the first 6 months of antiretroviral therapy, followed by a slower increase thereafter 5.
- In patients with cervical cancer, a higher CD4+:CD8+ ratio (>1.2) is associated with increased inflammatory markers, such as C-reactive protein (CRP) and blood HbA1c percent 6.
Key Findings
Key findings related to the CD4:CD8 ratio include:
- The ratio is a biomarker of persistent inflammation and immunosenescence in HIV-infected adults on effective antiretroviral therapy 2, 4.
- An elevated CD4:CD8 ratio is not specific to any particular disease or condition, and can be seen in various clinical contexts 3, 6.
- The ratio can be used to monitor immune dysfunction and viral reservoir size in immune-based clinical trials 2.
- The CD4:CD8 ratio is associated with clinical outcomes, such as mortality and morbidity, in HIV-infected adults and the general population 2, 4.