What it means
CD stands for "cluster of differentiation," a label scientists give to molecules on the surface of cells. T cells that carry CD8 are cytotoxic T cells: they find body cells infected with a virus, or cancer cells, and kill them. In HIV care the lab may report CD8 counts and the CD4-to-CD8 ratio, although the CD4 count is the main number followed.
At a glance
| Also written | CD8 cell, CD8 cells, CD8+, CD8 count |
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Related terms
immune system
The body's defense system of cells, tissues and organs that fights germs and other foreign substances.
immunodeficiency
A state in which the immune system is weaker than normal and cannot fight infection well.
CD4
A protein on the surface of helper T cells; a CD4 count measures how many of these immune cells are in the blood.