Soluble TREM2 Is Elevated in Pediatric Patients with Anti-NMDAR Encephalitis.

Objectives: Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is an autoimmune encephalitis that can lead to severe neurological impairments, particularly in pediatric patients. Effective biomarkers for diagnosis and prognosis are crucial for improved treatment outcomes. To evaluate the potential of soluble Triggering Receptor Expressed on Myeloid cells 2 (sTREM2) in cerebrospinal fluid (CSF) and serum as diagnostic and prognostic biomarkers in pediatric patients with anti-NMDAR encephalitis. Methods: The study included 21 children diagnosed with anti-NMDAR encephalitis and 27 children with non-inflammatory neurological disorders (OND) as controls. CSF and serum samples were collected from each patient. sTREM2 levels were measured using enzyme-linked immunosorbent assay (ELISA). Statistical analyses, including Mann-Whitney U test and ROC curve analysis, were performed to assess the diagnostic and prognostic value of sTREM2. Results: sTREM2 levels in CSF and serum were significantly higher in children with anti-NMDAR encephalitis compared to the OND group (p < 0.001). CSF sTREM2 levels showed a positive correlation with modified Rankin Scale (mRS) scores and a negative correlation with Glasgow Coma Scale (GCS) scores, suggesting an association with disease severity. ROC curve analysis demonstrated that CSF sTREM2 had a high diagnostic accuracy (AUC = 0.887, p < 0.001), while serum sTREM2 showed a slightly lower diagnostic accuracy (AUC = 0.848, p < 0.001). Patients with better prognoses had significantly lower CSF sTREM2 levels than those with poorer outcomes (p = 0.029). Conclusions: Elevated CSF sTREM2 levels were associated with increased neuroinflammation and poorer clinical outcomes in children with anti-NMDAR encephalitis. These findings suggest that CSF sTREM2 may serve as a valuable biomarker for the diagnosis and prognosis of pediatric anti-NMDAR encephalitis.