The CD4 +/CD8 + ratio in healthy adults is about 2/1, but an inverted CD4 +/CD8 + ratio (namely, less than 1/1) indicates an impaired immune system.
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.