An Exploratory Study on a Potential Biomarker for Seizures in Autoimmune Encephalitis

Autoimmune encephalitis (AE) is a severe neurological disorder often associated with seizures, but the risk factors for seizures in AE remain unclear. This study aimed to compare the clinical features and laboratory results between AE patients with and without seizures, focusing on the potential role of peripheral blood (PB) eosinophil counts as a predictive biomarker for seizures.

A retrospective cohort study was conducted on 106 AE patients admitted to the First Affiliated Hospital of Anhui Medical University. Patients were divided into two groups based on seizure presence: the seizure group (n=48) and the non-seizure group (n=58). A control group of 34 patients with AQP4-IgG-positive neuromyelitis optica spectrum disorder (NMOSD) was included. A control group of 34 patients with AQP4-IgG-positive neuromyelitis optica spectrum disorder (NMOSD), a demyelinating condition not typically associated with neuronal autoantibodies or seizures, was included for comparison. Clinical features and laboratory results were compared, with statistical analysis including univariate and multivariate logistic regression, as well as receiver operating characteristic (ROC) curve analysis.

The seizure group had significantly higher rates of prodromal symptoms, impaired consciousness, cerebrospinal fluid (CSF) protein (>0.45g/L) and CSF glucose levels, blood-brain barrier (BBB) dysfunction, and PB eosinophil counts compared to the non-seizure and control groups (all P<0.05). PB eosinophil counts were identified as an independent predictor of seizures.

Specific clinical and laboratory features are closely associated with seizures in AE. Increased PB eosinophil counts may serve as a novel biomarker for seizure risk in AE patients.