These two analyses suggest that while the CD4/CD8 ratio has prognostic significance in all treated adults, much of the harm associated with a low ratio is driven by the CD4 count (and presumably immunodeficiency) in those with low CD4+ T cell counts, while the harm associated with low ratio in those with higher CD4+ T cell counts is driven by CD8+ T cell count (and presumably inflammation). Here, CD4 is linked to immunodeficiency disease.