Where are macrophage-tropic viruses?

Results We examined virus in blood and CSF in eight subjects with advanced HIV disease and with neurocognitive involvement. All eight subjects had highly compartmentalized virus in comparing blood and CSF. In half of the subjects, the virus decayed rapidly in blood and CSF when therapy was initiated, and all env genes tested could infect cells only when there were high levels of CD4, both features indicative of infection of activated T cells in both the blood and central nervous system (CNS). In the other half of the subjects, virus decayed slowly in the CSF, but rapidly in the blood with the initiation of therapy, and the virus in the CSF could infect cells with low levels of CD4, indicative of the presence of macrophage-tropic virus in the CNS. However, the majority of the virus in the blood retained the requirement for high levels of CD4 for infection.