Serum neuron-specific enolase can predict the severity and outcome of anti-N-methyl-D-aspartate receptor encephalitis.

Background: Little is known about the association between serum neuron-specific enolase (NSE) concentration and anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. This study aims to investigate if serum NSE concentration is related to the clinical features of anti-NMDAR encephalitis.

Methods: Serum NSE levels were detected in 58 anti-NMDAR encephalitis cases, 58 matched healthy controls and 58 matched disease controls. Demographic features, clinical symptoms, cerebrospinal fluid parameters and brain MRI indexes of the cases were evaluated.

Results: Serum NSE concentrations were significant higher in case group than those in healthy controls and disease controls (both p < 0.001). Serum NSE concentrations in patients with mRS≥3 one year after onset were obviously higher than in those with mRS<3 (p < 0.001). Patients with status epilepticus or central hypoventilation had higher serum NSE levels than those without (p = 0.003 and p = 0.006). Serum NSE concentrations in cases with brain lesions or brain atrophy were significant higher than in those without (p = 0.001 and p < 0.001, respectively). Serum NSE concentrations were found to be significant higher in cases with limited response to treatment compared to those with favourable therapy outcomes (p < 0.001). Spearman's correlation analysis showed a significant positive association between serum NSE concentration and mRS score at the most critical time (max mRS) (r = 0.575, p < 0.001) and one year after onset (r = 0.705, p < 0.001). Cox regression results reflected that high serum NSE level was an independent predictor of poor prognosis in anti-NMDAR encephalitis group (p = 0.001), and the ROC curve threshold value was 15.72 ng/ml.

Conclusions: Serum NSE concentrations in anti-NMDAR encephalitis cases are higher than those in controls. It can be used to predict the brain damage degree and prognosis of anti-NMDAR encephalitis cases.