Serum PADI4 is Elevated in Neuro-Behçet’s Disease but is not Associated with Clinical or Cognitive Outcomes

Neutrophils contribute to inflammation by generating neutrophil extracellular traps (NETs), which are released through a mechanism called NETosis and accumulate in serum and inflamed tissues, thereby promoting endothelial damage and a procoagulant state (5).The pathergy test, a diagnostic tool for BD, is characterized by non-specific skin hypersensitivity and intensive neutrophil infiltration, which clinically mirrors this hyperinflammatory profile (6).Peptidylarginine deiminase type 4 (PADI4), a calcium ion-dependent enzyme, catalyzes protein citrullination by converting arginine to citrulline, thereby altering protein structure and function ( 7).It plays a critical role in inflammatory processes by mediating histone citrullination Abs tractAim: Peptidylarginine deiminase type 4 (PADI4), a key enzyme involved in neutrophil extracellular trap (NET) formation, has been implicated in the pathogenesis of autoinflammatory diseases, including Behçet's disease (BD).We aimed to evaluate serum PADI4 levels in neuro-BD (NBD) and to investigate their association with disease activity and clinical parameters.Methods: This study was designed as an analytical cross-sectional study between 2021 and 2023.A total of 25 patients with NBD, 45 with multiple sclerosis, 10 with neuromyelitis optica (NMO), and 19 healthy controls were enrolled.Serum PADI4 concentrations were measured using ELISA.Comprehensive neuropsychological assessments were conducted in the NBD group.Correlation analyses were performed to evaluate associations with cognitive and clinical parameters.Results: Serum PADI4 levels were significantly elevated in NBD patients compared to healthy controls but were comparable among patient groups.None of the cognitive and motor performance scores were correlated with PADI4 levels.NBD patients with a positive pathergy test showed significantly higher PADI4 levels.Conclusion: Neutrophil extracellular traposis may represent a shared inflammatory pathway across immune-mediated brain disorders.However, the lack of association between serum PADI4 levels and clinical or cognitive parameters in NBD suggests limited diagnostic and prognostic utility as a biomarker.