Cerebrospinal fluid human immunodeficiency virus type 1 RNA levels are elevated in neurocognitively impaired individuals with acquired immunodeficiency syndrome

To determine whether cerebrospinal fluid (CSF) viral burden measurements can assist in the evaluation of human immunodeficiency virus (HIV)-associated neurocognitive disorders, we quantified HIV type 1 (HIV-1) RNA in CSF. Because previous findings suggested that disease stage, lymphocytic pleocytosis, and HIV-1 RNA levels in plasma may influence CSF viral burden, these variables were examined as potential modifying factors. HIV-1 RNA levels were quantified by using a reverse transcriptase–polymerase chain reaction assay. Performance on a comprehensive neuropsychological (NP) battery was noted in 97 prospectively enrolled, HIV-infected subjects. Among subjects with acquired immunodeficiency syndrome (AIDS) (<200 CD⁴ lymphocytes), NP impairment was associated with significantly higher CSF RNA levels (3.1 vs 1.8 log₁₀ copies/ml; p = 0.02); most impaired subjects met criteria for HIV-associated dementia or minor cognitive–motor disorder. In subjects without AIDS, CSF RNA and NP impairment were unrelated. Before AIDS, CSF RNA was strongly correlated to plasma RNA and to pleocytosis, but in AIDS, CSF and plasma RNA were independent. In conclusion, we found elevated CSF HIV-1 RNA levels in NP impaired subjects with AIDS. Before AIDS, systemic viral replication, possibly through CD⁴⁺ mononuclear cell trafficking, may govern virus levels in CSF, whereas in AIDS, CD4 cell depletion may unmask a correlation between increased productive central nervous system HIV infection and clinical neurocognitive disorders.