Brain-Derived Tau as an Outcome Marker in Guillain-Barré Syndrome: A Retrospective Cohort Study

Biomarkers for predicting disease severity and outcome in Guillain-Barré syndrome (GBS) are scarce. We aimed to determine if brain-derived tau in serum (sBD-tau) and cerebrospinal fluid (CSF BD-tau) are associated with long-term outcome and disease severity in GBS.

In this retrospective study of 100 GBS patients, we measured sBD-tau and CSF BD-tau at diagnosis. Outcome was defined as GBS disability scale (GBSDS) > 2 and overall neuropathy limitation scale (ONLS) at 12 months, disease severity as respiratory support and ONLS at nadir. BD-tau levels were compared between groups and correlated with ONLS scores. Regression analyses and receiver operator characteristic curve analyses were performed for GBSDS > 2 at 12 months.

BD-tau levels were higher for GBSDS > 2 at 12 months in serum and CSF. Odds ratio for sBD-tau was 1.9 (95% CI 1.08-3.2, p = 0.03) and for CSF BD-tau was 5.9 (95% CI 1.4-25, p = 0.02). Area under curve for sBD-tau was 0.75 (95% CI 0.57-0.9, p < 0.001) and for CSF BD-tau was 0.78 (95% CI 0.65-0.9, p = 0.001). ONLS at 12 months correlated with sBD-tau (ρ = 0.34 [95% CI 0.12-0.53], p = 0.002) and CSF BD-tau (ρ = 0.33 [95% CI 0.08-0.54], p = 0.01). Statistically significant difference in BD-tau levels was not seen for respiratory support or ONLS at nadir.

BD-tau at GBS onset is associated with long-term outcome but not disease severity. Because BD-tau is essentially a CNS biomarker, our results suggest that CNS involvement influences recovery.