Abstract
BACKGROUND: There is an unmet need for predictive biomarkers in Guillain-Barré syndrome (GBS). We aimed to determine whether cerebrospinal fluid (CSF) alpha-internexin (AINX) concentrations are associated with disease severity and outcome in GBS. METHODS: This retrospective cohort included 100 GBS patients. AINX concentrations were measured at diagnosis using a sensitive Simoa assay. Disease severity at nadir was assessed with the GBS Disability Scale (GBSDS) and the need for mechanical ventilation. Poor outcome was defined as GBSDS > 2 at 12 months. Logistic regression with log-transformed AINX assessed associations with severe disease at nadir (GBSDS > 2), need for mechanical ventilation, and poor outcome at 12 months (GBSDS > 2). ROC curve analysis assessed the ability of AINX to predict poor outcome and compared its performance with previously reported biomarkers re-analyzed in this cohort. RESULTS: AINX concentrations at diagnosis were higher in patients with poor outcome and remained associated with poor outcome after adjustment for age (OR 12.48, 95% CI 1.20-129.1, p = 0.034). This association remained significant after additional adjustment for axonal subtypes (OR 26.38, 95% CI 1.12-619.77, p = 0.042). ROC analysis demonstrated good discriminative performance (AUC of 0.79, 95% CI 0.61-0.97, p = 0.002). The optimal cutoff of 2.9 ng/L yielded 50% sensitivity and 95.7% specificity. AINX concentrations were not associated with disease severity at nadir or with need for mechanical ventilation. CONCLUSIONS: Elevated CSF AINX at diagnosis was associated with poor long-term outcome in GBS, consistent with a possible contribution of CNS-related injury to recovery.