Optic, trigeminal, and facial neuropathy related to anti‐neurofascin 155 antibody

Abstract Objective To characterize the frequency and patterns of optic, trigeminal, and facial nerve involvement by neuroimaging and electrophysiology in IgG4 anti‐neurofascin 155 antibody‐positive (NF155+) chronic inflammatory demyelinating polyneuropathy (CIDP). Methods Thirteen IgG4 NF155+ CIDP patients with mean onset age of 34 years (11 men) were subjected to neurological examination, blink reflex, and visual‐evoked potential (VEP) testing, and axial and/or coronal T2‐weighted head magnetic resonance imaging (MRI). Results Among 13 patients, facial sensory impairment, facial weakness, and apparent visual impairment were observed in three (23.1%), two (15.4%), and two (15.4%) patients, respectively. All 12 patients tested had blink reflex abnormalities: absent and/or delayed R1 in 11 (91.7%), and absent and/or delayed R2 in 10 (83.3%). R1 latencies had strong positive correlations with serum anti‐NF155 antibody levels (r = 0.9, P ≤ 0.0001 on both sides) and distal and F wave latencies of the median and ulnar nerves. Absent and/or prolonged VEPs were observed in 10/13 (76.9%) patients and 17/26 (65.4%) eyes. On MRI, hypertrophy, and high signal intensity of trigeminal nerves were detected in 9/13 (69.2%) and 10/13 (76.9%) patients, respectively, whereas optic nerves were normal in all patients. The intra‐orbital trigeminal nerve width on coronal sections showed a significant positive correlation with disease duration. Interpretation Subclinical demyelination frequently occurs in the optic, trigeminal, and facial nerves in IgG4 NF155+ CIDP, suggesting that both central and peripheral myelin structures of the cranial nerves are involved in this condition, whereas nerve hypertrophy only develops in myelinated peripheral nerve fibers.