Metabolic Characterization of Cerebrospinal Fluid for Patients With Autoimmune Encephalitis: A Preliminary Study

Background: Metabolomics offers promise in uncovering potential biomarkers and understanding the pathophysiology of autoimmune encephalitis (AE), which is a cluster of disorders with the host immune system targeting self-antigens expressed in the central nervous system (CNS). In this research, our objective was to explore metabolic characterization in cerebrospinal fluid (CSF) from individuals with AE, aiming to shed light on the pathophysiology of AE.

Methods: A targeted approach was applied using an ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) system to study CSF metabolites in patients with AE (n = 18), and control subjects without neurological diseases (n = 17).

Results: A total of 21 potential biomarkers were acquired by getting the intersection of the differential metabolites from univariate statistics and multidimensional statistics between the AE (cell-based assay panel, CBA-panel) group and the control group. Specifically, the levels of pyruvic acid and oxoglutaric acid were notably elevated in the AE(CBA-panel) group compared to those in the control group, indicating that the dysregulated TCA cycle may play a pivotal role in the progression of AE(CBA-panel). Interestingly, 27 potential biomarkers were acquired by getting the intersection of the differential metabolites from univariate statistics and multidimensional statistics between the anti-N-methyl-D-aspartate receptor encephalitis (NMDARE) group and the control group, suggesting that the disparities between patients with greater homogeneity and the controls are amplified. In addition, seven differential metabolites were identified by the univariate statistics between the AE (tissue-based assay, TBA) group and the control group, including alpha-linolenic acid and gamma-linolenic acid, suggesting that dysregulated biosynthesis of unsaturated fatty acids and alpha-linolenic acid metabolism might be crucial in the AE(TBA) disease course.

Conclusion: Collectively, distinct metabolic profiles were evident in the CSF of the AE group compared to the control group, notably involving metabolites associated with mitochondrial dysfunction, which helped to elucidate the pathophysiology of AE.