Two Cases of Isolated Neurofilament Heavy Chain Antibody Syndrome

Objective Novel clinical and laboratory findings in anti-neurofilament heavy chain encephalitis Background Antibodies to mature components of neuronal intermediate filament (NIF) have been implicated several neurological disorders, including multiple sclerosis, amyotrophic lateral more recently, various autoimmune encephalitides. The include a-internexin, light chain. In the largest case series anti-NIF syndromes (McKeon et al, 2021), patients' cell-based assays revealed antibodies one, two or all three components. Heavy (anti-NfH) were present most, out four patients with encephalopathy cerebellar involvement. One was due a paraneoplastic phenomenon. Anti-NfH also elevated cases spasticity. It lone autoantibody one six aforementioned cases. Design/Methods N/A. Results Case 1: 37-year old female history ovarian carcinoma, treated 2016. Cognitive impairment started fall 2019, significant worsening point catatonia coma October 2020. Though improved, severe ataxia nystagmus persisted. Two MRI brain studies an EEG unremarkable, no radiological evidence cancer recurrence. Oligoclonal bands (in both CSF serum) serum anti-NfH elevated. 2: 59 year-old gradual cognitive decline since March 2018, followed by rapid deterioration Oct There limb weakness, rigidity, clonus witnessed seizure. showed intermittent rhythmic delta activity. indicated bilateral hippocampal atrophy. Protein Conclusions This contains first reported involvement from isolated anti-NfH. Also presented is PERMS any NIF antibody. Further research needed on quantitative qualitative factors syndromes. Specifically, relevance number antibodies, associations between phenotype specific antibody combination.