Cytokines in New‐Onset Refractory Status Epilepticus Predict Outcomes

Objective The objective of this study was to investigate inflammation using cerebrospinal fluid (CSF) and serum cytokines/chemokines in patients with new‐onset refractory status epilepticus (NORSE) to better understand the pathophysiology of NORSE and its consequences. Methods Patients with NORSE (n = 61, including n = 51 cryptogenic), including its subtype with prior fever known as febrile infection‐related epilepsy syndrome (FIRES), were compared with patients with other refractory status epilepticus (RSE; n = 37), and control patients without SE (n = 52). We measured 12 cytokines/chemokines in serum or CSF samples using multiplexed fluorescent bead‐based immunoassay detection. Cytokine levels were compared between patients with and without SE, and between the 51 patients with cryptogenic NORSE (cNORSE) and the 47 patients with a known‐etiology RSE (NORSE n = 10, other RSE n = 37), and correlated with outcomes. Results A significant increase of IL‐6, TNF‐α, CXCL8/IL‐8, CCL2, MIP‐1α, and IL‐12p70 pro‐inflammatory cytokines/chemokines was observed in patients with SE compared with patients without SE, in serum and CSF. Serum innate immunity pro‐inflammatory cytokines/chemokines (CXCL8, CCL2, and MIP‐1α) were significantly higher in patients with cNORSE compared to non‐cryptogenic RSE. Patients with NORSE with elevated innate immunity serum and CSF cytokine/chemokine levels had worse outcomes at discharge and at several months after the SE ended. Interpretation We identified significant differences in innate immunity serum and CSF cytokine/chemokine profiles between patients with cNORSE and non‐cryptogenic RSE. The elevation of innate immunity pro‐inflammatory cytokines in patients with NORSE correlated with worse short‐ and long‐term outcomes. These findings highlight the involvement of innate immunity‐related inflammation, including peripherally, and possibly of neutrophil‐related immunity in cNORSE pathogenesis and suggest the importance of utilizing specific anti‐inflammatory interventions. ANN NEUROL 2023;94:75–90