Growing Spectrum of Autoimmune Nodopathies

Purpose of Review: Recognition of node of Ranvier as the site of injury in inflammatory neuropathies contributed to discovery of antibodies against the nodal/paranodal structures. These antibodies mediate a unique type of inflammatory neuropathies that are different from typical chronic inflammatory demyelinating polyneuropathy. This review discusses the advancements made in the field of autoimmune neuropathies secondary to antibodies to nodal and paranodal proteins. Recent Findings: Neuropathies caused by antibodies to nodal-paranodal antigens including neurofascin 186, neurofascin 155, contactin1, and contactin-associated protein1 were termed as autoimmune nodopathies (AN) in 2021. Since the initial description almost a decade ago, newer cohorts have expanded the clinical spectrum of AN. In addition to IgG4, other subclasses of IgG such as IgG1/IgG3 have been identified, particularly in relation to acute presentations and anti-pan neurofascin antibody disease. In vitro and in vivo studies have also supported antibody-mediated pathogenicity of many of these biomarkers. Summary: Antibodies to nodal-paranodal antigens have emerged as a biomarker for a novel type of immune-mediated neuropathies. These antibodies have distinct pathogenic mechanisms and produce a unique set of clinicopathologic features. Their clinical profile and treatment may also vary depending on the antibody isotype. B cell depleting therapies are effective in managing some of these patients.