The CD4+/CD8+ ratio is the ratio of T helper cells (with the surface marker CD4) to cytotoxic T cells (with the surface marker CD8). CD4+ cells are anti-inflammatory, while CD8+ cells are pro-inflammatory.
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.
A reduced CD4+/CD8+ ratio is associated with reduced resistance to infection.
A declining CD4+/CD8+ ratio is associated with ageing, and is an indicator of immunosenescence.
HIV infection leads to low levels of CD4+ T cells (lowering the CD4+/CD8+ ratio) through a number of mechanisms, including killing of infected CD4+ T cells by CD8 cytotoxic lymphocytes that productively infected cells. When CD4+ T cell numbers decline below a critical level, cell-mediated immunity is lost, and the body becomes progressively more susceptible to opportunistic infections. Patients with tuberculosis show a reduced CD4+/CD8+ ratio.
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- Owen, Judith; Punt, Jenni; Stranford, Sharon (2013). Kuby Immunology. New York: W. H. Freeman and Company. p. 40.
- Yin Y, Qin J, Dai Y, Zeng F, Pei H, Wang J (2015). “The CD4+/CD8+ Ratio in Pulmonary Tuberculosis: Systematic and Meta-Analysis Article”. Iranian Journal of Public Health. 44 (2): 185–193. PMC 4401876. PMID 25905052.
- Kumar, Vinay (2012). Robbins Basic Pathology (9th ed.). p. 147. ISBN 9781455737871.