High CSF neurofilament heavy chain levels in neuromyelitis optica.

The neurofilament heavy chain (NfHSMI35), a biomarker of axonal damage in the CSF, was measured in patients with neuromyelitis optica (NMO) and multiple sclerosis (MS). Significantly high CSF NfHSMI35 levels (>0.73 ng/mL) were found in 6 of 24 (25%) of the patients with NMO but none of the patients with MS (0/24). This finding suggests that axonal damage is more severe in NMO than in MS.