ELectron microscopic abnormality and therapeutic efficacy in chronic inflammatory demyelinating polyneuropathy with anti-neurofascin155 immunoglobulin G4 antibody

Introduction Neurofascin155 (NF155) is a target antigen for autoantibodies in a subset of chronic inflammatory demyelinating polyneuropathy (CIDP). Methods We report the cases of 4 patients with anti-NF155 immunoglobulin G4 (IgG4) antibody-positive CIDP who underwent sural nerve biopsies. Results All patients were relatively young at onset. Three patients experienced tremors, and 2 patients had severe ataxia. Although the response to intravenous immunoglobulin was poor in all patients, plasma exchange and corticosteroids were at least partially effective. Immunoadsorption plasmapheresis was performed in 1 patient but was ineffective. Electron microscopic examination of sural nerve biopsies revealed loss of paranodal transverse bands in all patients. Discussion Anti-NF155 IgG4 antibody-positive CIDP shows distinctive clinicopathological features, indicating that the IgG4 antibody is directly associated with the pathogenic mechanisms of anti-NF155 IgG4 antibody-positive CIDP. Muscle Nerve, 2017