Potential Biomarker Identified for Antibody-Mediated Autoimmune Encephalitis

Plasma neurofilament light may serve as a useful biomarker among patients with antibody-mediated autoimmune encephalitis (AE), according to new findings presented at the American Neurological Association’s 145th Annual Meeting.

Researchers arrived at their conclusion after retrospectively assessing patients enrolled in the biorepository at the University of Colorado’s Rocky Mountain Multiple Sclerosis Center. Patients included in the analysis had a well-defined autoimmune neurological disease, and had been followed between 2014 and 2019.The Single Molecule Array (SIMOA) manufactured by Quanterix was used to test neurofilament light levels. Positive values were defined as neurofilament light levels of more than 10 pg/ml in accordance with normative data.

The results of the study indicated that, among 20 plasma and 8 cerebrospinal fluid (CSF) samples that had been stored in the biorepository, elevated plasma neurofilament light levels were observed in several types of AE, including AE mediated by glial fibrillary acidic protein (GFAP), glutamic acid decarboxylase (GAD)-65, leucine-rich glioma-inactivated (LGI1), glycine receptor, and N-methyl-D-aspartate (NMDA) receptor antibodies. The researchers observed higher neurofilament light levels among patients with untreated symptoms, active symptoms, or acute presentations.

The researchers noted that patients within 6 months of AE presentation had higher levels of neurofilament light (17.6 pg/ml) than those with greater time since presentation (5.8 pg/ml). They also observed a positive correlation between plasma and CSF (mean levels 39 pg/ml higher in CSF).

“Our findings support the use of plasma [neurofilament light] as a potential noninvasive biomarker in patients with antibody-mediated AE,” the researchers concluded.

—Christina Vogt

Piquet AL, Alvarez E, Bennett JL, et al. A retrospective, cross-sectional study evaluating plasma neurofilament light levels in autoimmune encephalitis. Ann Neurol. 2020;88(Suppl. 20). doi:10.1002/ana.25865