Abstract
BACKGROUND: Elevated neurofilament light chain (NfL) levels are associated with worse prognosis in Guillain-Barré syndrome (GBS). Our objectives were to determine the utility of serum NfL (sNfL), cerebrospinal fluid (CSF)/serum NfL ratio and NfL index as prognostic and diagnostic biomarkers for GBS. METHODS: We measured NfL in serum and/or CSF obtained from 96 GBS patients between 1989 and 2014 in western Sweden. The sNfL Z-scores, NfL ratios and NfL indices were calculated. Outcome was determined with the GBS disability scale (GBSDS) at 3 and 12 months. NfL parameters in GBS were compared with healthy controls (HC), multiple sclerosis (MS), and amyotrophic lateral sclerosis (ALS). RESULTS: The sNfL Z-score was higher for GBSDS > 2 at 3 months (median [IQR], 3.5 ng/L [3.2-4.0], vs 2.6 [1.7-3.4], p = 0.008) and at 12 months (3.6 ng/L [3.5-3.8] vs 2.6 [1.8-3.5], p = 0.049). NfL ratio and index were not associated with outcome. The area under the curve (AUC) for sNfL Z-score was 0.76 (95% CI 0.58-0.93, p < 0.0001) for GBSDS > 2 at 3 months. NfL ratio and index were lower in GBS than HC, MS, and ALS. The AUC for the NfL ratio was 0.66 (95% CI 0.55-0.78, p = 0.0018) and for the NfL index 0.86 (95% CI 0.78-0.93, p < 0.0001). DISCUSSION: Our results confirm sNfL as prognostic biomarker for GBS and the precision was improved using the age-adjusted sNfL Z score. NfL index and Qalb are potential diagnostic biomarkers for GBS.