Exposure of macrophages to interleukin-1 (IL-1), tumor necrosis factor α (TNFα), or interferon-γ, all of which have been shown to be present at elevated levels during the course of HIV-1 infection, has been shown to induce a reduction in C/EBPα mRNA levels while the levels of C/EBPβ and C/EBPδ expression increase [174]. Here, TNF is linked to HIV-1 infection.