Clinical importance of cerebrospinal fluid protein levels in HIV-associated cryptococcal meningitis; insights from a prospective cohort study in Uganda

Abstract Cerebrospinal fluid (CSF) protein levels exhibit high variability in HIV-associated cryptococcal meningitis; however, its clinical implications remain unclear. We analyzed data from 890 adults with HIV-associated cryptococcal meningitis randomized into two clinical trials in Uganda between 2015 and 2021. CSF protein was grouped into < 100 mg/dl (72%, n = 641) and ≥ 100 mg/dl (28%, n = 249). We described baseline clinical variables and 18-week mortality by CSF protein groups. Those with CSF protein ≥ 100 mg/dl were more likely to present with Glasgow coma scale score < 15 (P < .01), self-reported seizures at baseline (P = .02), higher CD4 T-cell count (P < .001), and higher CSF white blood cells (P < .001). Moreover, those with a baseline CSF protein ≥ 100 mg/dl also had a lower baseline CSF fungal burden (P < .001) and a higher percentage of sterile CSF cultures at day 14 (P = .02). Individuals with CSF protein ≥ 100 mg/dl demonstrated a more pronounced immune response consisting of upregulation of immune effector molecules, pro-inflammatory cytokines, T-helper cell type 1 and 17 cytokines, and immune-exhaustion marker (P < .05). 18-week mortality risk in individuals with a CSF protein < 100 mg/dl was 34% higher (unadjusted Hazard Ratio 1.34; 95% Confidence Interval, 1.05–1.70; P = .02) than those with CSF protein ≥ 100 mg/dl. In HIV-associated cryptococcal meningitis, individuals with baseline CSF protein ≥ 100 mg/dl more frequently presented with neurological symptoms, higher CSF inflammatory cytokines, reduced fungal burden, and lower mortality risk. The findings underscore the prognostic significance of baseline CSF protein levels in predicting disease severity and mortality risk in cryptococcal meningitis.