Optic Nerve Demyelination in IgG4 Anti-Neurofascin 155 Antibody-Positive Combined Central and Peripheral Demyelination Syndrome

Optic nerve demyelination is one of the clinical features of combined central and peripheral demyelination (CCPD), an entity with heterogenous immunopathogenesis and clinical characteristics, overlapping between multiple sclerosis (MS) and chronic inflammatory demyelinating polyneuropathy (CIDP). Of interest, earlier studies among patients with CIDP prior to discovery of antibodies against paranodal protein neurofascin 155 (anti-NF 155) also reported optic nerve dysfunction. We aimed to evaluate optic nerve demyelination among anti-NF 155 CIDP patients. We studied 2 patients with anti-NF 155 CIDP using visual-evoked potentials (VEP) and optical coherence tomography (OCT). Both patients had distal acquired demyelinating symmetric (DADS) subtype CIDP. Other common features were prominent sensory ataxia, hand tremors, significantly elevated cerebral spinal fluid protein, high titre anti-NF 155 antibodies and poor response to corticosteroid and intravenous immunoglobulin (IVIg). No central nervous system neuroradiological abnormality detected. Both had normal visual acuity and colour vision, but one had subclinical right relative afferent pupillary defect (RAPD). VEP of both showed bilateral prolonged P100 latencies. OCT for patient with RAPD demonstrated moderate to severe retinal nerve fibre layer (RNFL) thinning. Identification of optic nerve demyelination among subclinical CIDP with anti-NF 155 antibodies expanded the spectrum of demyelination within the subset of CCPD.