CD4 and HIV infectious disease: Reduced levels of miR-9 in CD4+ T cells have been shown to play a functional role in the higher levels of BLIMP-1 expression in patients with progressive chronic HIV infection who have reduced IL-2 expression and generalized T-cell dysfunction, indicating a novel miR-9/BLIMP-1/IL-2 axis that is dysregulated in progressive HIV infection [62].