Resident brain macrophages or microglia infected with HIV-1 or exposed to HIV-encoded proteins secrete proinflammatory cytokines e.g. interleukin-1?? (IL-1??) and tumor necrosis factor-?? (TNF-??) and chemokines e.g. CXCL10 and CXCL12, which cause neuronal death and pathogenic immune responses in the brain [14].