NEFL and Guillain-Barre syndrome: Some studies have shown that the CSF and serum concentrations of neurofilament heavy chain levels (NfH) were increased in children with GBS (11), and other studies have demonstrated that high serum neurofilament light chain levels (sNfL) were also increased and associated with poor prognosis in adult GBS (12), however, the correlation of CSF-NfL levels and outcome in children with GBS were not analyzed in these studies.