Dynamics of simian immunodeficiency virus populations in blood and cerebrospinal fluid over the full course of infection

BACKGROUND. Human immunodeficiency virus (HIV) replication and compartmentalization in the central nervous system, including in cerebrospinal fluid (CSF), are associated with severe neurological disease and may contribute to viral persistence during antiretroviral therapy. To understand the relationships between viral populations in multiple compartments, we performed a systematic longitudinal characterization of viral populations in blood plasma and CSF obtained at short time intervals over the full course of infection in 3 macaques infected with simian immunodeficiency virus (SIVsm strain E660). METHODS: Complex viral genetic populations in blood plasma and CSF were characterized using a heteroduplex tracking assay targeted to the V1/V2 hypervariable region of env. To identify signs of neurological disease, monocyte chemoattractant protein (MCP)-1 levels in CSF and CD68(+) monocyte/macrophage infiltration in brain tissues were quantified. RESULTS: Two patterns of blood/CSF viral dynamics were apparent as infection progressed: concordant blood/CSF viral evolution and discordant blood/CSF viral evolution. Perivascular CD68(+) cells in autopsy brain tissue and elevated CSF MCP-1 levels accompanied blood/CSF viral population discordance but not concordance. CONCLUSIONS: Two distinct patterns of blood/CSF viral population dynamics can be observed in SIV-infected macaques, and the patterns may be associated with different neurological disease outcomes.