Blood-CSF barrier and compartmentalization of CNS cellular immune response in HIV infection

•Soluble biomarkers reflecting cellular immune response were different in CSF than serum among HIV + participants.•CSF chemokines and cytokines correlated with CSF and plasma HIV RNA.•This suggest that HIV antigen load may drive cytokine responses.•CNS cellular immune response in HIV infection is compartmentalized.•It remains so despite the BCSFB dysfunction during HIV infection.•The compartmentalized immune response is markedly reduced by virology suppression.•BCSFB dysfunction persists on the virologic suppressed subgroup.•These results support the notion that the CNS behaves as a separate immunologic compartment.

HIV infection is persistent in the CNS, to evaluate the compartmentalization of the CNS immune response to HIV, we compared soluble markers of cellular immunity in the blood and CSF among HIV − (n = 19) and HIV + (n = 68), as well as among HIV participants with or without CSF pleocytosis. Dysfunction of the blood cerebrospinal fluid barrier (BCSFB) was common in HIV participants. CSF levels of TNFα, IFNγ, IL-2, IL-6, IL-7, IL-10, IP-10, MIP-1α, MIP-1β, and RANTES were significantly higher in participants with CSF pleocytosis (P < 0.05); serum levels of these biomarkers were comparable. The CNS immune response is compartmentalized, and remains so despite the BCSFB dysfunction during HIV infection; it is markedly reduced by virology suppression, although BCSFB dysfunction persists on this subgroup.

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