Relationships between plasma neurofilament light chain protein, cognition, and brain aging in people with HIV.

OBJECTIVE:Neurofilament light chain protein (NfL) is a marker of neuronal injury and neurodegeneration. Typically assessed in cerebrospinal fluid, recent advances have allowed this biomarker to be more easily measured in plasma. This study assesses plasma NfL in people with HIV (PWH) compared to people without HIV (PWoH), and its relationship with cognitive impairment, cardiovascular risk, and a neuroimaging metric of brain aging (brain-age gap). DESIGN:104 PWH (HIV RNA <50 copies/mL) and 42 PWoH provided blood samples and completed a cardiovascular risk score calculator, neuroimaging and cognitive testing. METHOD:Plasma NfL was compared between PWoH and PWH and assessed for relationships with age, HIV clinical markers, cardiovascular disease risk, cognition, and brain-age gap (difference between a brain-predicted age and chronological age). RESULTS:Plasma NfL was not significantly different between PWoH and PWH. Higher NfL related to increasing age in both groups. Plasma NfL was not associated with typical HIV disease variables. Within PWH, NfL was higher with higher cardiovascular risk, cognitive impairment and a greater brain-age gap. CONCLUSION:Virally suppressed PWH who are cognitively normal likely do not have significant ongoing neurodegeneration, as evidenced by similar plasma NfL compared to PWoH. However, NfL may represent a biomarker of cognitive impairment and brain aging in PWH. Further research examining NfL with longitudinal cognitive decline is needed to understand this relationship more fully.