Remarkably, the CD4/CD8 ratio was consistently lower across all types of non-AIDS events included in the definition (ischemic heart disease, stroke, end-stage kidney disease, and non-AIDS malignancies) and performed better than the CD4+ T-cell count, CD8+ T-cell count or nadir CD4 to discriminate subjects at risk of serious non-AIDS events. This evidence concerns the gene CD8A and AIDS.