Decreased NETosis-related regulators in neuromyelitis optica spectrum disorders after plasma exchange

•Identified significant reductions in NETosis-related regulators post-PLEX treatment in NMOSD.•Demonstrated a correlation between decreased IL-6 levels and improved neurological outcomes.•Observed increased anti-inflammatory cytokines, suggesting a potential regulatory effect of PLEX.•Provided evidence of PLEX’s impact on inflammatory mediator dynamics in NMOSD patients.•Highlighted potential biomarkers for assessing therapeutic response in NMOSD treatment. To investigate the impact of plasma exchange (PLEX) on NETosis-related regulators and their correlation with neurological improvement in NMOSD patients. Twelve aquaporin-4 antibodies seropositive NMOSD patients were enrolled. NETosis-related regulators (myeloperoxidase [MPO], citrullinated histone H3 [CIT-H3], peptidyl arginine deiminase 4 [PAD4], neutrophil elastase [NE], CD64), pro-inflammatory cytokines (IL-1, IL-6, IL-12, TNF-α) and anti-inflammatory cytokines (IL-10, TGF-β1) were quantitatively assessed before and after PLEX treatment. Clinical assessments included expanded disability status scale (EDSS) and visual outcome scale (VOS) scores. Following PLEX, all patients showed symptom improvement, with 66.7 % achieving marked-to-moderate improvement (MMI) at 3 months. Key regulators, such as MPO, CIT-H3, PAD4, NE, and pro-inflammatory cytokines such as IL-1, IL-6, IL-12, and TNF-α, exhibited a statistically significant decrease immediately after the initial PLEX session (P