CD4 and AIDS: The pattern of diminishing CD4-related progression risks at higher baseline CD4 (Figure 2c+d) was also observed in a recent multi-center analysis of patients starting immediate versus deferred ART [36]: Here, the prognostic value of CD4 − as measured by AIDS/death risks associated with deferring ART − was high at low CD4 thresholds, but marginal at thresholds in the range of 500 cells/μL.