CD8+ T-cells (levels of which remain elevated in the bloodstream during HIV infection), HIV-associated dysbiosis via microbial translocation (128, 133), and TRAIL [a proapoptotic ligand with an immune effector function promoting the eradication of infected or malignant cells (134)], are some of the identified factors responsible for CD4+ T-cell depletion. This evidence concerns the gene CD4 and HIV infectious disease.