<prompt> Normal ratio of CD4 T4 : CD8 T8 is2:011:023:011:03  <response>: Both CD4 and CD8 T cells contain several subsets. The CD4CD8 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 CD4CD8 ratio indicates an impaired immune system. Ref : 