CD4 and HIV-1 infection: We then demonstrated that in HIV-1 infection, the inhibition of CD34+ HSPC differentiation occurs due to a dynamic differential regulation of two microRNAs identified thus far, miR-15a (downregulated) and miR-24 (upregulated), which are secreted by the virus-infected CD4+ T-lymphocytes and indirectly target(ed) the CD34+ cells to inhibit hematopoiesis (Padmanabhan et al., 2020).