Plasma and antibody glycomic biomarkers of time to HIV rebound and viral setpoint.

Objective: HIV cure research urgently needs to identify pre-analytic treatment interruption (ATI) biomarkers of time-to-viral-rebound and viral setpoint to mitigate the risk of ATI and accelerate development of a cure. We previously reported that galactosylated IgG glycans, G2, negatively correlate with cell-associated HIV DNA and RNA during antiretroviral therapy (ART). We hypothesized that this and other plasma glycomic traits can predict time-to-viral-rebound and viral setpoint upon ART cessation.

Design: We profiled the circulating glycomes (plasma and bulk IgG) of two geographically distinct cohorts: Philadelphia Cohort - 24 HIV-infected, ART-suppressed individuals who had participated in an open-ended ATI study without concurrent immunomodulatory agents. Johannesburg Cohort - 23 HIV-infected, ART-suppressed individuals who had participated in a 2-week ATI.

Methods: Capillary electrophoresis and lectin microarray were used for glycomic analyses. Cox proportional-hazards model and log-rank test were used for statistical analyses.

Results: Higher pre-ATI levels of the IgG glycan, G2, were significantly associated with a longer time-to-viral-rebound (hazard ratio = 0.12, P = 0.05). In addition to G2, we identified several predictive glycomic traits in plasma, for example, levels of FA2BG1, a non-sialylated, core-fucosylated glycan, associated with a longer time-to-viral-rebound (hazard ratio = 0.023, P = 0.05), whereas FA2G2S1, a sialylated glycan, associated with a shorter time-to-viral-rebound (hazard ratio = 24.1, P = 0.028). Additionally, pre-ATI plasma glycomic signatures associated with a lower viral setpoint, for example, T-antigen (Galβ1-3GalNAc) (r = 0.75, P = 0.0007), or a higher viral setpoint, for example, polylactosamine (r = -0.58, P = 0.01). These results were initially validated in the Johannesburg Cohort.

Conclusion: We describe first-in-class, non-invasive, plasma and IgG glycomic biomarkers that inform time-to-viral-rebound and viral setpoint in two geographically distinct cohorts.