ABSTRACT
BACKGROUND: Dengue vascular permeability syndrome is the primary cause of death in severe dengue infections. The protective versus potentially pathogenic role of dengue NS1 antibodies are not well understood. The main goal of this analysis was to characterize the relationship between free NS1 concentration and NS1 antibody titers in primary and secondary dengue infection in order to better understand the presence and duration of NS1 antibody complexes in clinical dengue infections. METHODS: Hospitalized participants with acute dengue infection were recruited from Northern Colombia between 2018 to 2020. Symptom assessment including dengue signs and symptoms, chart review and blood collection was performed. Primary versus secondary Dengue was assessed serologically. NS1 titers and anti-NS1 antibodies were measured daily. RESULTS: Patients with secondary infection have higher antibody titers than those in primary infection, and we find a negative correlation between anti-NS1 antibody titer and NS1 protein. We demonstrate that in a subset of secondary infection, there are indeed NS1 antibody-antigen complexes at the admission day during the febrile phase that are not detectable by the recovery phase. Furthermore, dengue infection status is associated with higher circulating sialidases. DISCUSSION: The negative correlation between antibody and protein suggests that antibodies may play a role in clearing this viral protein.