Asymptomatic Cerebrospinal Fluid HIV-1 Escape: Incidence and Consequences

Background The incidence and clinical relevance of asymptomatic cerebrospinal fluid escape (CSF-E) during antiretroviral therapy (ART) is uncertain. We examined the impact and incidence of asymptomatic CSF-E in a Swedish HIV cohort. Methods Neuroasymptomatic people living with HIV (PLWH) who have been on ART for at least six months with suppressed plasma viral load were followed longitudinally. CSF-E was defined as either increased CSF HIV-1 RNA with concurrent plasma suppression or as CSF HIV-1 RNA exceeding that in plasma when both were quantifiable. Paired CSF and plasma were analyzed for HIV-1 RNA, neopterin, neurofilament light protein (NfL), white blood cell (WBC) count, and albumin ratio. Results Asymptomatic CSF-E (cut-off 50 copies/mL) was found in 4/173 PLWH (2%) and 5/449 samples (1%). The corresponding proportions were 8% of PLWH and 4% for samples using a 20 copies/mL cut-off for CSF HIV-1 RNA. CSF-E samples (cut-off 20 copies/mL) had a 25% higher geometric mean of CSF neopterin (P = .01) and 8% higher albumin ratio (P = .04) compared to samples without CSF-E. No differences were observed in CSF NfL levels (P = .8). The odds ratio for increased CSF WBC (≥ 3 cells/μL) in samples with CSF-E was 3.9 (P = .004), compared to samples without elevated CSF viral load. Conclusion Asymptomatic CSF-E was identified in only four (2%) PLWH, with no cases of continuous CSF-E observed. Increased CSF HIV-1 RNA was associated with biomarkers of CNS immune activation and blood-brain-barrier impairment, but not with biomarkers of neuronal injury.