Elevated levels of cerebrospinal fluid CHIT1 correlate with disease activity in neuromyelitis optica spectrum disorder.

Background: Neuromyelitis optica spectrum disorder (NMOSD) is a severe autoimmune inflammatory disease of the central nervous system characterized by microglial activation and neuroinflammation. Chitotriosidase (CHIT1), a microglial activation biomarker, has been implicated in neurodegenerative and neuroinflammatory diseases, but its role in NMOSD remains unclear.

Methods: Thirty-four patients with NMOSD, 30 healthy controls (HCs), and 30 patients with other noninflammatory neurological disorders (ONNDs) were included. Cerebrospinal fluid (CSF) and serum CHIT1 levels were measured via enzyme-linked immunosorbent assay. Comprehensive clinical parameters were collected from all participants. Statistical comparisons and receiver operating characteristic (ROC) curve analyses were performed to evaluate the diagnostic performance of CHIT1 for NMOSD.

Results: CSF CHIT1 levels were significantly higher in the NMOSD group than in the ONND group (p < 0.001). In contrast, serum CHIT1 levels did not differ significantly between NMOSD patients and either ONND or HC groups. Subgroup analysis revealed higher CSF CHIT1 concentrations in NMOSD patients with gadolinium-enhancing lesions than in those without such lesions (p = 0.035). ROC analysis demonstrated that CSF CHIT1 could distinguish NMOSD patients from patients with ONNDs, with an area under the curve of 0.730. Additionally, CSF CHIT1 levels correlated positively with the Expanded Disability Status Scale score (r = 0.457, p = 0.007).

Conclusion: An elevated CSF CHIT1 level in NMOSD patients is significantly associated with greater disease severity, suggesting its potential as a diagnostic and prognostic biomarker. These findings highlight the role of CHIT1 in the pathogenesis of NMOSD and warrant further investigation into its clinical applicability.