Autoimmune neuropathy

Such neuropathies as Guillain-Barre syndrome (GBS) and chronic inflammatory demyelinating polyneuropathy (CIDP) are caused by autoimmune mechanisms targeting peripheral nervous system and called as autoimmune neuropathies. Anti-glycolipid antibodies are frequently detected in the acute-phase sera from patients with GBS. Each antibody is closely associated with a certain clinical feature (anti-GM1 IgG and pure motor GBS, anti-GQ1b IgG and Fisher syndrome, etc). Mixtures of two different glycolipids (glycolipid complexes, GLCs) are sometimes specifically recognized by IgG antibodies in GBS. Those antibodies may recognize novel epitopes formed by carbohydrate portions of two glycolipids, such as GD1a/GD1b, GM1/GalNAc-GD1a, GM1/GQ1b, etc. Glycoarray is an efficient method for detecting antibodies against numerous GLCs. In contrast, anti-glycolipid antibodies are rarely detected in CIDP. Recently, IgG4 antibodies against neurofascin (NF) 155, a paranodal protein, are reported to be present in about 10% of patients with CIDP. Patients with anti-NF 155 antibody-positive CIDP frequently have ataxia, tremor, distal-dominant weakness, and remarkably high CSF protein level. Abnormal paranodal lesions such as loss of the transvers bands were observed by electron microscope in those patients. Plasmapheresis (PP) and intravenous immunoglobulin (IVIg) are effective for GBS, and steroids as well as PP and IVIg are effective for CIDP. However, the responses to IVIg were reported to be poor in anti-NF 155 antibody-positive CIDP. The auto-antibodies can be used as biomarkers and some of them are involved in the pathogenetic mechanisms. Development of novel therapy is required for severe and intractable cases of GBS and CIDP.