Monocyte infiltration of the brain is central to the pathogenesis of HIV-1 encephalitis. The cytokines promoting recruitment of monocytes into the central nervous system during HIV-1 infection are not established. In this study, we evaluated human cerebrospinal fluid from patients with HIV-1 infection for transforming growth factor beta1 (TGFbeta1) and monocyte chemotactic protein-1 (MCP-1) using a quantitative sandwich enzyme-linked immunoassays. Cytokine levels were compared to those from patients with multiple sclerosis and normal controls. In cerebrospinal fluid of patients with HIV-1 infection and CD4<500 cells/mm3, both TGFbeta1 and MCP-1 were significantly elevated compared to those with CD4>500 cells/mm3, multiple sclerosis, and controls.